JP5580051B2 - Cylinder lubricating oil composition for crosshead type diesel engine - Google Patents

Description

  The present invention relates to a cylinder lubricating oil composition for a crosshead type diesel engine and a method for lubricating a cylinder of a crosshead type diesel engine using the composition.

A crosshead type diesel engine used for marine diesel engines uses a cylinder oil that lubricates between the cylinders and a system oil that controls lubrication and cooling of other parts. The cylinder oil is required to have a function of maintaining a proper viscosity necessary for lubrication between the cylinder and the piston (piston ring) and a cleanliness necessary for proper movement of the piston and the piston ring.
This engine usually has a problem of cylinder corrosion due to acidic components such as sulfuric acid generated by combustion because high sulfur fuel having a high sulfur content is used from the viewpoint of economy. In order to prevent this problem, the cylinder oil is also required to have a function of neutralizing the generated acidic components and preventing corrosion.

Recent cross-head type diesel engines have further improved performance, for example, increased cylinder diameter of bore size of 70 cm or more, piston stroke for realizing an ultra-long stroke with an average piston speed of 8 m / s or more. There is a tendency to increase the combustion pressure, ie, the net effective pressure (BMEP) is 1.8 MPa or more. These improvements for improving the performance are factors that increase the wall temperature of the piston and cylinder. In addition, an increase in combustion pressure causes an increase in the dropping point of sulfuric acid, so that sulfuric acid corrosion of the cylinder is likely to occur. In order to prevent this sulfuric acid corrosion, for example, a method of raising the cylinder wall temperature to 250 ° C. or higher is employed. In recent years, the amount of lubricating oil injected into the cylinder has also been decreasing from the viewpoint of economy.
In view of the above, the lubrication environment of the cylinder is becoming more severe, and the cylinder oil is particularly required to have higher heat resistance than before.

Conventionally, as marine diesel engine oil, there are many low-cost marine diesel engine oils that contain a normal overbased metal detergent as a main component and maintain wear resistance. Recently, however, diesel engine oils containing various types of metallic detergents such as salicylate, sulfonate, phenate, or complex detergents and containing extreme pressure agents and dispersants have been developed. (Patent Documents 1 to 5). However, cylinder oils used in recent crosshead type diesel engines are required to further improve wear prevention and seizure resistance at a lower cost.
JP 2002-275491 A JP-T-2002-515933 Japanese translation of PCT publication No. 2002-501974 Japanese translation of PCT publication No. 2002-500026 JP 2002-241780 A

An object of the present invention is to provide a cylinder lubricating oil composition for a crosshead engine having particularly excellent heat resistance and excellent seizure resistance, and a method for lubricating a cylinder of a crosshead engine using the composition.
Another object of the present invention is to provide a cylinder lubricating oil composition for a crosshead engine that is particularly excellent in heat resistance, has fluidity that can spread in a short time on the cylinder surface, and has excellent wear prevention and seizure resistance. It is to provide.

According to the present invention, a lubricating base oil composed of at least one of a mineral oil and a synthetic oil, and an alkali metal salt, an alkaline earth metal salt or an (over) basic alkali metal salt of an alkylphenol sulfide represented by the following formula (1): A phenate-based metal detergent (A) having a base number of 100 to 400 mg KOH / g and an alkylphenol sulfide represented by the formula (2) to be described later, wherein the salt is a salt having 5 to 50 mol% of a metal salt having m of 4 or more An alkali metal salt, an alkaline earth metal salt or a (over) basic salt thereof, and a phenate metal detergent (B) other than the above (A) having a base number of 100 to 400 mgKOH / g, (A) is contained in an amount of 3 to 20% by mass based on the total amount of the composition, and (B) is contained in an amount of 1 to 10% by mass on the basis of the total amount of the composition. The mass ratio of (A) and (B) (B) / (A) is 0.1 1.5, for a crosshead type diesel engine cylinder lubricant composition is provided.
Moreover, according to this invention, the lubricating method of the cylinder of a crosshead type diesel engine including supplying the said lubricating oil composition to the cylinder of a crosshead type diesel engine is provided.
Furthermore, according to the present invention, there is provided use of the above lubricating oil composition for producing a heat resistance improver that improves the heat resistance of a cylinder of a crosshead type diesel engine.

Since the lubricating oil composition of the present invention contains the phenate metal detergent (A), it is excellent in heat resistance, and the phenate metal detergent other than the phenate metal detergent (A) and the component (A). By including a cleaning agent, in addition to heat resistance, it is excellent in fluidity and excellent in spreadability on a sliding surface at high temperature. Therefore, it is suitable as a cylinder lubricant composition for a crosshead type diesel engine. In particular, the bore size is increased to 70 cm or more, the ultra-long stroke that the average piston speed is 8 m / s or more, and further 8.5 m / s or more, and the combustion pressure is 1.8 MPa or more in net effective pressure (BMEP). In addition, a cylinder of a two-stroke cycle diesel engine that is operated under a condition that satisfies any or all of the conditions of 1.9 MPa or more, cylinder wall temperature of 250 ° C. or more, further 260 ° C. or more, particularly 270 ° C. or more. Particularly effective as a cylinder lubricating oil composition to be lubricated.
The lubricating oil composition of the present invention can also be used as various marine diesel engine oils other than crosshead type diesel engine cylinder oils and cogeneration diesel engine oils.

Hereinafter, the present invention will be described in more detail.
There is no particular limitation on the lubricating base oil in the cylinder lubricating oil composition for a crosshead type diesel engine of the present invention (hereinafter simply referred to as the composition of the present invention). Mineral oil and / or synthetic oil used for ordinary lubricating oil Oil can be used.
As mineral oil, lube oil fraction obtained by distillation under reduced pressure of atmospheric residue obtained by atmospheric distillation of crude oil, solvent removal, solvent extraction, hydrocracking, solvent dewaxing, hydrorefining, etc. Examples of the lubricating base oil produced by the method of isomerizing GTL WAX (gas-tuly liquid wax) produced by one or more of the above-mentioned treatments or wax isomerized mineral oil, Fischer-Tropsch process, etc. .

The total aromatic content of the mineral oil is not particularly limited, but is preferably 40% by mass or less, more preferably 30% by mass or less. The total aromatic content may be 0% by mass, but is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more in terms of the solubility of the additive. . When the total aromatic content of the base oil exceeds 40% by mass, the oxidation stability may be inferior.
In addition, the said total aromatic content means the aromatic fraction (aromatic fraction) content measured based on ASTMD2549. In general, this aromatic fraction includes alkylbenzene, alkylnaphthalene, anthracene, phenanthrene, alkylated products thereof, compounds in which four or more benzene rings are condensed, and heterogeneous compounds such as pyridines, quinolines, phenols, and naphthols. Compounds having aromatics are included.

  Although there is no restriction | limiting in particular in the sulfur content in mineral oil, 1 mass% or less is preferable and 0.5 mass% or less is more preferable. Although 0 mass% may be sufficient as a sulfur content, Preferably it is 0.1 mass% or more, More preferably, it is 0.2 mass% or more. By including a certain amount of sulfur in the mineral oil, the solubility of the additive can be sufficiently increased.

  Synthetic oils include, for example, polybutene or hydrides thereof; poly α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl Diesters such as adipate and di-2-ethylhexyl sebacate; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate and pentaerythritol pelargonate; dicarboxylics such as dibutyl maleate Copolymers of acids and α-olefins having 2 to 30 carbon atoms; aromatic synthetic oils such as alkylnaphthalenes, alkylbenzenes, and aromatic esters, or mixtures thereof.

In the present invention, mineral oil and / or synthetic oil can be used as the lubricating base oil. For example, 1 or more types of mineral oil, 1 or more types of synthetic oil, the mixed oil of 1 or more types of mineral oil and 1 or more types of synthetic oil is mentioned.
The kinematic viscosity of the lubricating base oil is not particularly limited, but the kinematic viscosity at 100 ° C. is preferably 4 to 50 mm ² / s, more preferably 6 to 40 mm ² / s, and particularly preferably 8 to 35 mm ² / s. It is. When the kinematic viscosity at 100 ° C. of the lubricating base oil exceeds 50 mm ² / s, the low temperature viscosity characteristics may be deteriorated. On the other hand, when the kinematic viscosity is less than 4 mm ² / s, the oil film formation at the lubrication site is insufficient, so that the lubricity is inferior and the evaporation loss of the base oil may be increased.

In the present invention, the lubricating base oil may contain a lubricating base oil having a kinematic viscosity at 100 ° C. of less than 4 to 17 mm ² / s and / or a kinematic viscosity at 100 ° C. of 17 to 50 mm ² / s. preferable.
Examples of the lubricating base oil having a kinematic viscosity at 100 ° C. of less than 4 to 17 mm ² / s include mineral base oils such as SAE 10 to 40 and synthetic base oils. A preferred kinematic viscosity 5.6 mm ² / s or more, more preferably 9.3 mm ² / s or more, preferably 14 mm ² / s or less, more preferably 12.5 mm ² / s.
Examples of the lubricant base oil having a kinematic viscosity at 100 ° C. of 17 to 50 mm ² / s include mineral base oils and synthetic base oils such as SAE50 and bright stock, and the preferable kinematic viscosity is 20 mm ² / s. or more, more preferably 25 mm ² / s or more, preferably 40 mm ² / s or less, more preferably 35 mm ² / s.
In the present invention, a lubricant base oil having a kinematic viscosity at 100 ° C. of less than 4 to 17 mm ² / s is contained, for example, 40% by mass or more or 50% by mass or more based on the total amount of the lubricant base oil. In addition, a lubricating base oil having a kinematic viscosity at 100 ° C. of 17 to 50 mm ² / s can be blended.

The evaporation loss amount of the lubricating base oil is preferably 20% by mass or less, more preferably 16% by mass or less, and particularly preferably 10% by mass or less in terms of NOACK evaporation. When the NOACK evaporation amount of the lubricating base oil exceeds 20% by mass, the evaporation loss in the lubricating oil composition is large, which may cause an increase in viscosity.
In this specification, the NOACK evaporation amount is a value obtained by measuring the evaporation amount of lubricating oil measured in accordance with ASTM D 5800.

  The viscosity index of the lubricating base oil is not particularly limited, but the value is preferably 80 or higher, more preferably 90 or higher, and still more preferably 100 or higher so that excellent viscosity characteristics can be obtained from low temperature to high temperature. The upper limit of the viscosity index is not particularly limited, and those of about 135 to 180 such as normal paraffin, slack wax, GTL wax, isoparaffin mineral oil obtained by isomerizing these, complex ester base oil, HVI-PAO base About 150 to 250 such as oil can also be used. From the viewpoint of the solubility and storage stability of the additive, the upper limit of the viscosity index is preferably 120 or less, and more preferably 110 or less.

The phenate-based metal detergent (A) used in the present invention (hereinafter sometimes referred to as the component (A)) has an alkylphenol sulfide metal salt containing 5 or more alkylphenol structures in the same molecule. ) Alkali metal salt, alkaline earth metal salt or (over) basic salt of alkylphenol sulfide having a structure represented by formula (1), which essentially contains a polymer having a degree of polymerization m of 4 or more Agents.
Examples of the alkali metal or alkaline earth metal include sodium, potassium, magnesium, barium, and calcium. Magnesium or calcium is preferable, and calcium is particularly preferable.

  In the formula (1), each R independently represents a linear or branched, saturated or unsaturated alkyl group having 6 to 21 carbon atoms. Carbon number of this alkyl group becomes like this. Preferably it is 9-18, More preferably, it is 9-15. If the carbon number is shorter than 6, the solubility in the lubricating base oil may be poor. If the carbon number is longer than 21, the production is difficult and the heat resistance may be poor. The degree of polymerization m in the formula (1) is 1 to 10, and x is 1 to 3.

In the component (A), the content ratio of the alkylphenol sulfide metal salt having a polymerization degree m of 4 or more represented by the formula (1) is preferably 5 to 50 mol%. It is preferable that a component (A) contains the component whose m is 4-5 among the components whose polymerization degree m shown by Formula (1) which is an essential component is 4 or more. Furthermore, it is preferable to contain 5 mol% or more of the component whose m is 4-5.
The base number of component (A) is preferably in the range of 50 to 400 mgKOH / g, more preferably in the range of 100 to 350 mgKOH / g, and still more preferably in the range of 120 to 300 mgKOH / g. When the base number is 50 mgKOH / g or less, corrosion wear may increase, and when it exceeds 400 mgKOH / g, there may be a problem in solubility.
Here, the base number is defined in JIS K2501 “Petroleum products and lubricants—Neutralization number test method”. Means the base number measured by the perchloric acid method according to the above.

The metal ratio of component (A) is not particularly limited, and usually the lower limit is 1 or more, preferably 2 or more, particularly preferably 2.5 or more, and the upper limit is preferably 20 or less, more preferably 15 or less, and particularly preferably 10 It is as follows.
In the present specification, the metal ratio means the valence of the metal element in the phenate-based metal detergent × metal element content (mol%) / soap group content (mol%). Here, the metal element means calcium, magnesium, etc., and the soap group means a phenol group.

  In the composition of the present invention, the content ratio of the component (A) is preferably 3 to 20% by mass, more preferably 6 to 12% by mass, and particularly preferably 8 to 12% by mass based on the total amount of the composition. . When the content is less than 3% by mass, the required heat resistance may not be obtained, and when it exceeds 20% by mass, there may be a problem in fluidity.

The composition of the present invention can further contain a metal-based detergent (B) other than the component (A) (hereinafter also referred to as component (B)).
As the component (B), for example, one or more selected from the group consisting of phenate metal detergents other than the component (A), sulfonate detergents, salicylate detergents, carboxylate detergents, and phosphonate detergents. In particular, by including a phenate metal detergent other than the component (A) (hereinafter sometimes referred to as the component (B1)), the fluidity on the cylinder sliding surface of the composition is further improved. can do.

Examples of the component (B1) include alkali metal salts, alkaline earth metal salts, or (over) basic salts of alkylphenol sulfides having a structure represented by the formula (2).
Examples of the alkali metal or alkaline earth metal include sodium, potassium, magnesium, barium, and calcium. Magnesium or calcium is preferable, and calcium is particularly preferable.

  In the formula (2), each R independently represents a linear or branched, saturated or unsaturated alkyl group having 6 to 21 carbon atoms. Carbon number of this alkyl group becomes like this. Preferably it is 9-18, More preferably, it is 9-15. If the carbon number is shorter than 6, the solubility in the lubricating base oil may be poor. If the carbon number is longer than 21, the production is difficult and the heat resistance may be poor. In the formula (2), the degree of polymerization n is 1 to 3, and x is 1 to 3.

The base number of component (B1) is preferably in the range of 50 to 400 mgKOH / g, more preferably in the range of 100 to 350 mgKOH / g, and still more preferably in the range of 120 to 300 mgKOH / g. When the base number is 50 mgKOH / g or less, corrosion wear may increase, and when it exceeds 400 mgKOH / g, there may be a problem in solubility.
Here, the base number is defined in JIS K2501 “Petroleum products and lubricants—Neutralization number test method”. Means the base number measured by the perchloric acid method according to the above.
The metal ratio of the component (B1) is not particularly limited, and usually the lower limit is 1 or more, preferably 2 or more, particularly preferably 2.5 or more, and the upper limit is preferably 20 or less, more preferably 15 or less, and particularly preferably 10 It is as follows.

  In the composition of the present invention, the content ratio of the component (A) when the component (B1) is essential is preferably 3 to 20% by mass, more preferably 4 to 15% by mass, based on the total amount of the composition. More preferably, it is 6-12 mass%, Most preferably, it is 8-12 mass%. When the content is less than 3% by mass, the required heat resistance may not be obtained, and when it exceeds 20% by mass, there may be a problem in fluidity.

In the composition of the present invention, the proportion when the component (B1) is contained is usually 1 to 10% by mass, preferably 2 to 9% by mass, more preferably 3 to 8% by mass, based on the total amount of the composition. . When the content is less than 1% by mass, the fluidity may not be improved sufficiently, and when it exceeds 10% by mass, the required heat resistance may not be obtained.
In the composition of the present invention, when the component (B1) is contained, the ratio of the component (B1) / the component (A) is preferably 0.1 to 1.5, more preferably 0.2 to 1.2. Preferably, 0.3 to 1.0 is more preferable. If this ratio is less than 0.1, the fluidity may not be improved sufficiently, and if it exceeds 1.5, the required heat resistance may not be obtained.

As the sulfonate detergent as the component (B), for example, an alkali metal salt of an alkyl aromatic sulfonic acid obtained by sulfonated an alkyl aromatic compound having a weight average molecular weight of 1300 to 1500, preferably 400 to 700 Alkaline earth metal salts or their (over) basic salts can be used. Examples of the alkali metal or alkaline earth metal include sodium, potassium, magnesium, barium, and calcium. Magnesium or calcium is preferable, and calcium is particularly preferable.
Examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

  Examples of petroleum sulfonic acids include those obtained by sulfonating alkyl aromatic compounds of a lubricating oil fraction of mineral oil and so-called mahoganic acid that is by-produced during white oil production. The synthetic sulfonic acid has a linear or branched alkyl group obtained, for example, as a by-product from an alkylbenzene production plant used as a raw material for a detergent, or obtained by alkylating a polyolefin with benzene. Examples thereof include those obtained by sulfonating alkylbenzene or those obtained by sulfonating alkylnaphthalene such as dinonylnaphthalene. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but usually fuming sulfuric acid or sulfuric anhydride is used.

(B) As a salicylate type detergent as a component, for example, an alkali metal having one hydrocarbon group having 1 to 19 carbon atoms, an alkaline earth metal salicylate or a (over) basic salt thereof, 20 to 40 carbon atoms An alkali metal having one hydrocarbon group, an alkaline earth metal salicylate or a (per) basic salt thereof, an alkali metal having two or more hydrocarbon groups having 1 to 40 carbon atoms, an alkaline earth metal salicylate, or Its (over) basic salt is mentioned. These hydrocarbon groups may be the same or different. In these, it is desirable to use the alkali metal, alkaline-earth metal salicylate, or its (over) basic salt which has one C8-C19 hydrocarbon group at the point which is excellent in low-temperature fluidity | liquidity.
Examples of the alkali metal or alkaline earth metal include sodium, potassium, magnesium, barium, and calcium. Magnesium and / or calcium are preferable, and calcium is particularly preferably used.

In the component (B), the base number of the component (B) other than the component (B1) is preferably in the range of 100 to 500 mgKOH / g, more preferably in the range of 120 to 450 mgKOH / g, and in the range of 150 to 400 mgKOH / g. Is more preferable. When this base number is less than 100 mgKOH / g, corrosion wear may increase, and when it exceeds 500 mgKOH / g, there may be a problem in solubility.
Here, the base number is defined in JIS K2501 “Petroleum products and lubricants—Neutralization number test method”. Means the base number measured by the perchloric acid method according to the above.
In the component (B), the metal ratio of the component (B) other than the component (B1) is not particularly limited, but the lower limit is 1 or more, preferably 2 or more, particularly preferably 2.5 or more, and the upper limit is preferably 20 In the following, it is more preferable to use those of 15 or less, particularly preferably 10 or less.
In the composition of the present invention, the proportion in the case of containing the component (B) other than the component (B1) is usually 5 to 30% by mass, preferably 6 to 20% by mass, particularly preferably based on the total amount of the composition. 7 to 15% by mass.

The composition of the present invention comprises an ashless dispersant (C) (hereinafter sometimes referred to as (C) component) and / or an extreme pressure agent / antiwear agent (D) (hereinafter sometimes referred to as (D) component). It is preferable to contain.
As the component (C), any ashless dispersant used in lubricating oils can be used. For example, a linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms in the molecule. And at least one nitrogen-containing compound or derivative thereof, a Mannich dispersant, or a modified product of alkenyl succinimide. In use, one kind or two or more kinds arbitrarily selected from these can be blended.
In the case where the carbon number of the alkyl group or alkenyl group of the nitrogen-containing compound or derivative thereof is less than 40, the solubility in the lubricating oil base oil is reduced, whereas in the case where the carbon number of the alkyl group or alkenyl group exceeds 400, The low-temperature fluidity of the lubricating oil composition may be deteriorated. The alkyl group or alkenyl group may be linear or branched, but is preferably a component derived from an olefin oligomer such as propylene, 1-butene, isobutylene, or a co-oligomer of ethylene and propylene. Examples thereof include a branched alkyl group and a branched alkenyl group.

Examples of the component (C) include one or more compounds selected from the following components (C1) to (C3).
(C1) Succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof,
(C2) benzylamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof,
(C3) A polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof.

(C1) As a component, the compound shown by Formula (3) or (4) can be illustrated.

In the formula (3), R ²⁰ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and h represents an integer of 1 to 5, preferably 2 to 4. On the other hand, in formula (4), R ²¹ and R ²² each independently represent an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and particularly preferably a polybutenyl group. I represents an integer of 0 to 4, preferably 1 to 3.

The component (C1) includes a so-called monotype succinimide represented by the formula (3) in which succinic anhydride is added to one end of the polyamine, and a formula (4) in which succinic anhydride is added to both ends of the polyamine. Although the so-called bis-type succinimide represented is included, the composition of the present invention may include any of them or a mixture thereof.
There is no restriction | limiting in particular in the manufacturing method of the succinimide which is (C1) component, For example, the alkyl obtained by making the compound which has a C40-400 alkyl group or an alkenyl group react with maleic anhydride at 100-200 degreeC. It is obtained by reacting succinic acid or alkenyl succinic acid with a polyamine.
Specific examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

(C2) As a component, the compound represented by Formula (5) can be illustrated.

In the formula (5), R ²³ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and j represents an integer of 1 to 5, preferably 2 to 4.
The method for producing benzylamine as component (C2) is not particularly limited. For example, a polyolefin such as propylene oligomer, polybutene, or ethylene-α-olefin copolymer is reacted with phenol to form alkylphenol, and then formaldehyde is added thereto. And polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine can be obtained by reacting them with Mannich reaction.

(C3) As a component, the compound represented by Formula (6) can be illustrated.
^{_{R 24 -NH- (CH 2 CH 2}} NH) k -H (6)
In the formula (6), R ²⁴ represents an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and k represents an integer of 1 to 5, preferably 2 to 4.
The production method of the polyamine which is the component (C3) is not particularly limited. For example, after chlorinating a polyolefin such as a propylene oligomer, polybutene, or ethylene-α-olefin copolymer, ammonia, ethylenediamine, diethylenetriamine, triethylene is added thereto. It can be obtained by reacting a polyamine such as tetramine, tetraethylenepentamine, or pentaethylenehexamine.

  Examples of the derivative of the nitrogen-containing compound mentioned as an example of the component (C) include, for example, monocarboxylic acids such as fatty acids, oxalic acid, phthalic acid, trimellitic acid having 1 to 30 carbon atoms in the nitrogen-containing compound described above. Remaining amino by reacting polycarboxylic acids having 2 to 30 carbon atoms such as pyromellitic acid or their anhydrides or ester compounds, alkylene oxides having 2 to 6 carbon atoms, hydroxy (poly) oxyalkylene carbonate, etc. Modified compounds by so-called oxygen-containing organic compounds obtained by neutralizing or amidating some or all of the groups and / or imino groups; boric acid is allowed to act on the aforementioned nitrogen-containing compounds to leave the remaining amino groups and / or iminos A so-called boron-modified compound in which a part or all of the group is neutralized or amidated; phosphoric acid is allowed to act on the above-mentioned nitrogen-containing compound to leave a residue A so-called phosphoric acid-modified compound obtained by neutralizing or amidating part or all of an amino group and / or imino group; a sulfur-modified compound obtained by allowing a sulfur compound to act on the nitrogen-containing compound described above; and the nitrogen-containing compound described above And modified compounds in which two or more kinds of modifications selected from modification with oxygen-containing organic compounds, boron modification, phosphoric acid modification, and sulfur modification are combined. Among these derivatives, boric acid-modified compounds of alkenyl succinimide, especially boric acid-modified compounds of bis-type alkenyl succinimide, further improve heat resistance by using the above-mentioned components (A) to (C) in combination. Can be made.

In the composition of the present invention, the proportion in the case of containing the component (C) is usually 0.005 to 0.4% by mass, preferably 0.01 to 0.2% by mass as the nitrogen amount based on the total amount of the composition. %, More preferably 0.01 to 0.1% by mass, particularly preferably 0.02 to 0.05% by mass. Further, when a boron-containing ashless dispersant is used as the component (C), the mass ratio (B / N ratio) between the boron content and the nitrogen content is not particularly limited, but is preferably 0.5 to 1. More preferably, it is 0.7-0.9. The higher the B / N ratio is, the easier it is to improve the wear prevention and seizure resistance. Moreover, when using a boron containing ashless dispersant, the content rate does not have a restriction | limiting in particular, However, Preferably it is 0.001-0.1 mass% as a boron amount on the basis of the composition whole quantity, More preferably, it is 0.005. -0.05 mass%, Most preferably, it is 0.01-0.04 mass%.
In the present invention, as the component (C), the boron content is 0.5% by mass or more, more preferably 1.0% by mass or more, further preferably 1.5% by mass or more, and particularly preferably 1.8% by mass. It is most desirable to include a boron-containing ashless dispersant, particularly a bis-type boron-containing succinimide-based ashless dispersant.
Here, the boron-containing ashless dispersant having a boron content of 0.5% by mass or more includes 10 to 90% by mass, preferably 30 to 70% by mass, for example, a diluent oil such as mineral oil or synthetic oil. The boron content usually means the boron content in a state containing diluent oil.

As the component (D), any extreme pressure agent / antiwear agent used for lubricating oil can be used. For example, sulfur-based, phosphorus-based, sulfur-phosphorus-based extreme pressure agents and the like can be used. Specifically, for example, phosphites, thiophosphites, dithiophosphites, trithiosuboxides. Phosphate esters, phosphate esters, thiophosphate esters, dithiophosphate esters, trithiophosphate esters, amine salts thereof, metal salts thereof, derivatives thereof, dithiocarbamate, zinc dithiocarbamate, molybdenum dithiocarbamate, Examples thereof include disulfides, polysulfides, sulfurized olefins, and sulfurized fats and oils.
In the present invention, it is preferable to use zinc dithiophosphate and / or polysulfides as the component (D).

  When the component (D) is used in the composition of the present invention, the content ratio is not particularly limited, but is generally 0.05 to 5% by mass, preferably 0.1 to 2% by mass, based on the total amount of the composition. Most preferably, it is 0.2-1 mass%. When the content of the component (D) is less than 0.05% by mass, the effect of further improving the wear resistance and seizure resistance is small. On the other hand, when the content exceeds 5% by mass, the high temperature cleanliness of the composition is high. There is a risk of significant deterioration.

  In addition to the above-described composition, the composition of the present invention may be added to any lubricating oil commonly used in lubricating oils depending on its purpose in order to further improve its performance or add other required performance. An agent can be further contained. Examples of such additives include antioxidants, friction modifiers, viscosity index improvers, corrosion inhibitors, rust inhibitors, demulsifiers, metal deactivators, antifoaming agents, and colorants. .

Examples of the antioxidant include ashless antioxidants such as phenols and amines; and metal antioxidants such as copper and molybdenum. The ratio in the case of containing these is 0.1-5 mass% normally on the composition whole quantity basis.
Examples of the friction modifier include ashless friction modifiers such as fatty acid esters, aliphatic amines, and fatty acid amides; and metal friction modifiers such as molybdenum dithiocarbamate and molybdenum dithiophosphate. The ratio in the case of containing these is 0.1-5 mass% normally on the composition whole quantity basis.

  Examples of the viscosity index improver include, for example, a polymethacrylate viscosity index improver, an olefin copolymer viscosity index improver, a styrene-diene copolymer viscosity index improver, and a styrene-maleic anhydride copolymer viscosity index improver. Or a polyalkyl styrene type viscosity index improver is mentioned. The weight average molecular weight of these viscosity index improvers is usually 800 to 1,000,000, preferably 100,000 to 900,000. Moreover, the ratio in the case of containing a viscosity index improver is 0.1-20 mass% normally on the composition whole quantity basis.

Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds.
Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.
Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, or β- (o-carboxybenzylthio) propiononitrile.
Examples of antifoaming agents include silicone oils having a kinematic viscosity at 25 ° C. of less than 0.1 to 100 mm ² / s, alkenyl succinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long chain fatty acids, methyl salicylates and o. -Hydroxybenzyl alcohol, aluminum stearate, potassium oleate, N-dialkyl-allylamine nitroaminoalkanol, aromatic amine salt of isoamyl octyl phosphate, alkyl alkylene diphosphate, metal derivative of thioether, metal derivative of disulfide, aliphatic hydrocarbon And fluorine compounds, triethylsilane, dichlorosilane, alkylphenyl polyethylene glycol ether sulfide, and fluoroalkyl ether.

  When these additives are contained in the composition of the present invention, the content is based on the total amount of the composition, and is usually 0.005 to 5% by mass for a corrosion inhibitor, a rust inhibitor and an anti-emulsifier, respectively. The activator is usually selected from the range of 0.005 to 1% by mass, and the antifoaming agent is usually selected from the range of 0.0005 to 1% by mass.

The kinematic viscosity at 100 ° C. of the composition of the present invention is not particularly limited, but is preferably 6 to 50 mm ² / s, more preferably 9.3 to 30 mm ² / s, and particularly preferably 12.5 to 21.9 mm. ² / s. The kinematic viscosity at 100 ° C. here refers to the kinematic viscosity at 100 ° C. as defined in ASTM D-445.

  The base number of the composition of the present invention is not particularly limited, but preferably 5 to 5 in order to add excellent high temperature cleanliness and acid neutralization performance even when using a high sulfur fuel containing asphaltenes. The lower limit is more preferably 10 mgKOH / g or more, still more preferably 20 mgKOH / g or more, and the upper limit is more preferably 90 mgKOH / g or less, still more preferably 80 mgKOH / g or less. Here, the base number refers to a base number measured by ASTM D-2896.

In the composition of the present invention, the lower limit of the amount of metal is preferably 0.2% by mass or more, more preferably 0.4% by mass or more, still more preferably 0.7% by mass or more, and the upper limit is preferably 3.6%. It is at most mass%, more preferably at most 3.2 mass%, even more preferably at most 2.9 mass%. When the metal content is less than 0.2% by mass, the neutralizing power of the acidic substance generated by combustion is not sufficient, and the high temperature cleanliness may not be sufficiently exhibited. On the other hand, when it exceeds 3.6% by mass, the ash after adhering to the piston and burning adheres to the piston, which may increase the wear of the cylinder.
The amount of sulfated ash in the composition of the present invention is not particularly limited, but the lower limit is preferably 1.2% by mass or more, more preferably 2% by mass or more, particularly preferably 3% by mass or more, and the upper limit is preferably 20%. It is 10 mass% or less, More preferably, it is 10 mass% or less. The sulfated ash here refers to 5. of JIS K2272. The value measured by the method specified in “Testing method for sulfated ash” is mainly attributable to the metal-containing additive.

The method of lubricating a cylinder of a crosshead type diesel engine of the present invention includes supplying the above-described lubricating oil composition of the present invention to a cylinder of the crosshead type diesel engine.
As a cross-head type diesel engine, the bore size is increased to 70 cm or more, the super-long stroke and the combustion pressure are the net effective pressure with an average piston speed of 8 m / s or more, and further 8.5 m / s or more. (BMEP) is operated under a condition that satisfies any or all of the following conditions: 1.8 MPa or more, further 1.9 MPa or more, cylinder wall temperature 250 ° C. or more, further 260 ° C. or more, particularly 270 ° C. or more. A two-stroke cycle diesel engine is preferred.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these.
Examples 1-1 to 1-4 and Comparative Examples 1 and 2
Lubricating oil compositions (Examples 1-1 to 1-4) in the present invention having the compositions shown in Table 1 and comparative lubricating oil compositions (Comparative Examples 1 and 2) were prepared. About the obtained composition, high temperature cleanliness was evaluated by the hot tube test. The results are shown in Table 1.
The base oil used here is a combination of SAE 30 Group I base oil (sulfur content 0.03% by mass or more, saturation content less than 90% by mass, viscosity index 80 to 120) and bright stock. The kinematic viscosity at 100 ° C. of the composition with the agent added was adjusted to 20 mm ² / s, and the metal detergent was added so that the base number of the composition was 70 mg KOH / g.

(Heat resistance test method)
The heat resistance was evaluated according to JPI-5S-55-99 (hot tube test) for evaluating high temperature deposit prevention of engine oil. In the hot tube test, the test temperature is increased from 300 ° C. in increments of 5 ° C., the coking temperature is determined, and the “coking temperature −5 ° C.” is defined as the HTT heat-resistant temperature. A cleanliness score was calculated. HTT heat-resistant temperature of 320 degreeC or more was determined to be a pass.

  As apparent from the results in Table 1, the composition containing the component (A) in the present invention exhibits excellent heat resistance in the hot tube test. Contrary to this, when a phenate detergent other than the component (A) was used, both the HTT heat resistance temperature and the score were inferior.

Examples 2-1 to 2-7 and Comparative Example 3
The lubricating oil compositions (Examples 2-1 to 2-7) in the present invention and the comparative lubricating oil composition (Comparative Example 3) of the composition shown in Table 2 were prepared. About the obtained composition, the expansibility was evaluated by the high temperature fluidity test, and the high temperature detergency was evaluated by the hot tube test. The results are shown in Table 2.
The base oil used here is a combination of SAE30 Group I base oil (sulfur content 0.03% by mass or more, saturation content less than 90% by mass, viscosity index 80 to 120) and bright stock. The kinematic viscosity at 100 ° C. of the composition with the additive added was adjusted to 20 mm ² / s, and a metal detergent was added so that the base number of the composition was 70 mg KOH / g. Examples 1 to 7 are cases where the component (A) and the component (B1) are used in combination, and Comparative Example 3 is a case where the component (B) is used alone. In either case, calcium sulfonate was added as component (B).

(High temperature fluidity test method)
A steel plate polished with abrasive paper # 400 is tilted and fixed at 10 degrees. A plate-like heater is installed under the plate so that the entire steel plate can be heated to 320 ° C. A drop of sample oil is dripped onto the top of the steel, and the speed at which this oil flows down along the slope is measured.
This test simulates the spread of the cylinder oil supplied to the cylinder wall of the engine, meaning that the faster the oil spreads, the wider the range of lubrication of the cylinder wall. It means that it becomes possible.
(Heat resistance test method)
The heat resistance was evaluated according to JPI-5S-55-99 (hot tube test) for evaluating high temperature deposit prevention of engine oil. In the hot tube test, a score of 7.0 or higher after a test time of 16 hours at a test temperature of 320 ° C. or higher was determined to be acceptable.

  As is clear from the results in Table 2, the composition containing the component (A) and the component (B1) in the present invention was excellent in both the fluidity test and the hot tube test. On the contrary, in the case of only the component (B1), the fluidity was good, but the results of the hot tube test were bad.

Claims (4)

A lubricating base oil comprising at least one of mineral oil and synthetic oil;
Alkali metal salts of alkylphenol sulfide which is shown by the formula (1), an alkaline earth metal salt or a (per) basic salts, m has 4 or more metal salts 5 to 50 mol%, base number 100-400 mg KOH / g phenate-based metal detergent (A),
Alkali metal salt, alkaline earth metal salt or its (over) basic salt of alkylphenol sulfide represented by the formula (2) having a base number of 100 to 400 mgKOH / g, other than the phenate metal other than (A) A cleaning agent (B),
(A) is 3 to 20% by mass based on the total amount of the composition, and (B) is contained in an amount of 1 to 10% by mass based on the total amount of the composition.
The mass ratio (B) / (A) of the (A) and the (B) is 0.1 to 1.5.
Cylinder lubricating oil composition for crosshead type diesel engines.

[In Formula (1), R shows a C6-C21 linear or branched, saturated or unsaturated alkyl group each independently. m is 1-10 and x is 1-3. ]

[In Formula (2), R shows a C6-C21 linear or branched, saturated or unsaturated alkyl group each independently. n is 1-3 and x is 1-3. ]   The composition according to claim 1, further comprising at least one of an ashless dispersant (C) and an extreme pressure agent / antiwear agent (D).   The composition according to claim 2, comprising a boron-containing ashless dispersant as the ashless dispersant (C).   A method for lubricating a cylinder of a crosshead type diesel engine, comprising supplying the composition according to claim 1 to the cylinder of the crosshead type diesel engine.