KR20150074017A - System lubrication oil composition for crosshead diesel engine - Google Patents

Abstract

The present invention relates to a crosshead type lubricating oil for a diesel engine system which is low in generation of sediments even when a base oil of group II or group III is used and has excellent high temperature cleanliness and resistance to coking (heat resistance), and has a dynamic viscosity at 100 DEG C of 4.0 to 12.6 & (A-1) having a kinematic viscosity at 100 占 폚 of 16.3 to 60 mm2 / s and a base oil (A-2) having a saturated hydrocarbon content of less than 90 mass% and having a kinematic viscosity at 100 占 폚 of 8.5 (B) and zinc dithiophosphate (C) in a base oil (A) having an aromatic content of not less than 1.05 mass% and not less than 12.6 mm 2 / s and not less than 1.05 mass% And a phosphorus content of 200 to 1000 mass ppm. The present invention provides a cross-head type lubricating oil composition for a diesel engine system.

Description

TECHNICAL FIELD [0001] The present invention relates to a crosshead type diesel engine lubricating oil composition,

The present invention relates to a system lubricating oil composition for a crosshead type diesel engine.

In the crosshead-type diesel engine, cylinder oil for lubricating between the cylinder and the piston and system oil for cooling and lubrication of the other parts are used (refer to Patent Documents 1 to 6). In addition, the system oil for a ship crosshead type diesel engine is supplied to the piston undercrown to cool the piston, but since the piston undercrown is hot, the heat exchange efficiency is lowered when the sludge is deposited, and the piston damage ). Further, when the drip oil of the cylinder oil is mixed and the system oil is contaminated, the heat resistance is lowered, so that it is easy to coke and the sludge may accumulate on the cooling surface of the piston. For this reason, high temperature cleanliness and coking resistance are important performances for the system oil of a crosshead type diesel engine.

However, the base oil used in the conventional lubricating oil is mainly produced by separating the gasoline or the light oil component from the crude oil by further distillation under reduced pressure from the distillation residue of the atmospheric distillation residue, extracting the required viscosity fraction, . This base oil is classified as Group I in the API base oil category.

In recent years, since the sulfur content and the aromatic content in the base oil adversely affect the oxidation stability of the base oil, the residual oil is hydrocracked to produce a base oil having an extremely small sulfur content and aromatic content. Furthermore, wax produced by the Fischer-Trosch process or petroleum wax produced as a by-product in the production of the base oil is hydrocracked to produce a base oil having a very high viscosity index. Base oils produced by hydrocracking them are classified as group II or III in the API base oil classification.

In the purification process of the base oil (Group I) of the former, a process of selectively extracting and removing an unstable compound centered on an aromatic content by using a solvent such as furfural, phenol and methylpyrrolidone is employed have. On the other hand, in the latter method of producing a base oil, the aromatic content in the base oil is extremely small and it is not necessary to undergo the above-described solvent purification process. For this reason, the amount of base oil (i.e., group I base oil) that has undergone a relatively solvent refining process is decreasing.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2007-231115 [Patent Document 2] JP-A-2010-523733 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2002-275491 [Patent Document 4] Japanese Published Patent Specification No. 2009-185293 [Patent Document 5] Japanese Published Patent Specification No. 2010-519376 [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2011-74387

Under such circumstances, when the present inventor used the base oil of the group II or the group III as the base oil of the cross-head type diesel engine system oil as a result of using the base oil of the group I as a base oil, if the drip oil of the cylinder oil is mixed into the system oil, (Heat resistance) is lowered.

It is therefore an object of the present invention to provide a crosshead type system lubricating oil for a diesel engine which is less liable to deposit and which is excellent in high temperature cleanliness and coking resistance (heat resistance) even when using a base oil of group II or group III .

As a result of intensive studies to solve the above problems, the present inventors have found that by adding a metal-based cleaner and zinc dithiophosphate to a base oil having a three or more aromatic content of 1.05 mass% or more while using a base oil of group II or group III, And the present invention has been completed.

That is, the system lubricating oil composition for a crosshead type diesel engine of the present invention comprises:

(A-1) having a kinematic viscosity at 100 DEG C of 4.0 to 12.6 mm < 2 > / s,

(A-2) having a kinematic viscosity at 100 DEG C of 16.3 to 60 mm < 2 > / s and a saturated hydrocarbon content of less than 90 mass%

(A) having a kinematic viscosity at 100 DEG C of 8.5 to 12.6 mm < 2 > / s and an aromatic content of 3 or more rings of 1.05 mass% or more,

A metal-based detergent (B)

Zinc dithiophosphate (C) is blended,

The base has an amount of 4 to 20 mg KOH / g,

And the phosphorus content is 200 to 1000 mass ppm.

In the system lubricating oil composition for a crosshead type diesel engine of the present invention, the base oil (A-1) preferably has a saturated hydrocarbon content of 90 mass% or more.

In the lubricating oil composition for a crosshead type diesel engine of the present invention, it is also preferable that the base oil (A-1) is a group II base oil and / or a group III base oil.

In the lubricating oil composition for a crosshead type diesel engine of the present invention, it is preferable that the base oil (A-2) is a by-product extract at the time of solvent refining in the process of producing a mineral oil base oil.

Further, in the system lubricating oil composition for a crosshead type diesel engine of the present invention, it is preferable that the metallic detergent (B) is Ca salicylate.

According to the present invention, it is possible to provide a system lube oil for a crosshead type diesel engine having less sediment generation and excellent in high-temperature cleanliness and caking resistance (heat resistance) even when using a base oil of group II or group III.

Hereinafter, the present invention will be described in detail. The base oil (A) of the system lubricating oil composition for a crosshead type diesel engine of the present invention (hereinafter simply referred to as a lubricating oil composition) has a base oil (A-1) having a kinematic viscosity at 100 ° C of 4.0 to 12.6 mm 2 / (A-2) having a kinematic viscosity of 16.3 to 60 mm 2 / s and a saturated hydrocarbon content of less than 90 mass%, a kinematic viscosity at 100 ° C of 8.5 to 12.6 mm 2 / s, an aromatic content of 3 or more rings of 1.05 Mass% or more.

The kinematic viscosity at 100 캜 of the base oil (A-1) is 4.0 to 12.6 mm 2 / s, preferably 4.5 to 12.0 mm 2 / s, particularly preferably 5.0 to 11.5 mm 2 / s. When the kinematic viscosity of the base oil (A-1) at 100 캜 exceeds 12.6 mm 2 / s, the low temperature viscosity property deteriorates. On the other hand, when the kinematic viscosity is less than 4.0 mm 2 / s, The lubricity is lowered and the evaporation loss of the lubricating oil base oil is increased. In the present invention, the kinematic viscosity at 100 캜 refers to the kinematic viscosity at 100 캜 specified in ASTM D-445.

The base oil (A-1) preferably has a saturated hydrocarbon content of 90 mass% or more, and is preferably classified into Group II and Group III in the classification according to the base oil classification by API (American Petroleum Institute). In the present invention, the saturated hydrocarbon content means a value measured by ASTM D-2007.

There is no particular limitation on the production method of the base oil (A-1), but generally, the atmospheric pressure residue obtained by atmospheric distillation of crude oil is subjected to desulfurization and hydrogenolysis, and classified into a predetermined viscosity grade, Dewatering or contact dewatering and, if necessary, further solvent extraction and hydrogenation to base oil.

The base oil (A-1) is further subjected to a vacuum distillation process in which the atmospheric distillation residue is further subjected to vacuum distillation, classified into necessary viscosity grades, and then subjected to a solvent degassing process such as solvent purification, hydrogenation purification, Based wax isomerization lubricant oil produced by hydroisomerization of a petroleum wax produced as a by-product in the process, or a GTL wax isomerization produced by a process of isomerizing a GTL wax (WAX) (gas to liquid wax) produced by a Fischer-Tropsch process or the like Lubricant base oils and the like. In this case, the basic production process of the wax isomerization lubricant base oil is the same as that of the hydrogenolysis base oil.

The total aromatic content of the base oil (A-1) is not particularly limited, but is 3 mass% or less in one embodiment, 1 mass% or less in another embodiment, and 0.5 mass% or less in another embodiment. Here, the smaller the total aromatic content of the base oil (A-1), that is, the lower the aromatic content, the easier the problem of solubility of the sludge. The above-mentioned total aromatic content means the aromatic oil content measured according to ASTM D2549.

The sulfur content of the base oil (A-1) is not particularly limited, but is 0.03 mass% or less in one embodiment and 0.01 mass% or less in another embodiment. In another embodiment, the base oil (A- 1) is substantially free of sulfur. Here, the lower the sulfur content, the higher the refining degree, and the solubility problem of the sludge is more likely to occur.

The blending amount of the above base oil (A-1) is preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 75% by mass or more, and preferably 95% % Or less, more preferably 93 mass% or less.

On the other hand, the kinematic viscosity of the base oil (A-2) at 100 캜 is 16.3 to 60 mm 2 / s, preferably 20 to 40 mm 2 / s, particularly preferably 25 to 35 mm 2 / s. If the kinematic viscosity of the base oil (A-2) exceeds 100 mm < 2 > / s, the workability is deteriorated. On the other hand, if the kinematic viscosity at 100 DEG C is less than 16.3 mm & have.

The base oil (A-2) has a saturated hydrocarbon content of less than 90 mass%, preferably 1 to 60 mass%, particularly preferably 5 to 15 mass%. When the saturated hydrocarbon content of the base oil (A-2) is 90 mass% or more, it is difficult to inhibit the formation of sediments and the high-temperature cleanliness is deteriorated.

Examples of the base oil (A-2) include base oils classified into group I in the classification according to the base oil classification by Extract and API (American Petroleum Institute) produced as a by-product in the process of producing a mineral oil base oil, Extracts that are a by-product of solvent refining in the process of manufacturing a mineral oil base oil base oil are preferred.

Extracts produced as a by-product in the solvent purification contain 70 to 99% of aromatic compounds by column chromatography, 15% or more of aromatic hydrocarbon compounds (% C _A ) according to the compositional analysis method defined in ASTM D2140, And 5 to 25 mass% of PCA (polycyclic aromatic compound) extracted by DMSO (dimethyl sulfoxide) according to the IP346 method according to the British Petroleum Institute.

The production method of the extractions produced as a by-product at the time of solvent purification is not particularly limited. As an example, the lubricating oil fraction and the reduced pressure distillation residue obtained by vacuum distillation of crude oil are dewatered and then subjected to dewaxing treatment or hydrogenation purification treatment , An oil obtained by subjecting oil to solvent extraction with a solvent having an affinity for an aromatic hydrocarbon is used.

The solvent extraction treatment refers to an operation of using a solvent to separate raffinate having a low aromatic content into extract having a large aromatic content and examples of the solvent include furfural, phenol, cresol, sulfolane, N- Methylpyrrolidone, dimethylsulfoxide, formylmorpholine, glycol solvents and the like are used.

However, in recent years, carcinogenicity by PCA (Polycyclic Aromatic) has been emphasized. In Europe, there is a movement to regulate the use of oils containing 3% by mass or more of PCA in the oil and the like. Therefore, the extract has a content of PCA (polycyclic aromatic compound) extracted by DMSO (dimethyl sulfoxide) of less than 3% by mass, that is, according to the IP346 method according to the British Petroleum Institute, is 3% .

The content of PCA in the extract varies depending on the solvent used, the solvent used, the solvent / solvent ratio in the solvent extraction process, the reaction temperature, and the like. Therefore, by appropriately changing these conditions, it is possible to control the PCA content to 3 mass% or less. In addition, hydrocracking treatment may also be preferably used to control the PCA content of the extract to 3 mass% or less.

With respect to the extracult having a PCA content of less than 3% by mass, the production method thereof is not limited, but the following production methods can be exemplified.

Japanese Patent Laid-Open No. 6-505524 discloses a process for producing a process oil in which a reduced pressure distillation residue is subjected to dehydration treatment and the obtained oil is subjected to a dewaxing treatment to reduce PCA content to less than 3 mass%. In addition, JP-A-7-501346 discloses a non-cancerous bright stock extract and a defatted oil having a low PCA content and a process for producing the defatted oil. In this publication, oil or deaeration oil obtained by deaeration of a residue in a vacuum distillation column There is disclosed an oil in which an aromatic compound is reduced by extraction treatment or an oil obtained by a dewaxing treatment thereof.

In addition, Japanese Patent Application Laid-Open No. 11-80751 discloses a method of extracting a petroleum hydrocarbon mixture from a petroleum hydrocarbon mixture having a polycyclic aromatic compound content of 1.6 mass% by IP346 % Of an aromatic hydrocarbon solvent having a polycyclic aromatic compound content of less than 3% by mass obtained by the IP346 test method in the second stage solvent extraction.

In addition, Japanese Patent Laid-Open No. 2000-80208 discloses a raw material preparation process for producing a raw material oil selected from the group consisting of lubricating oil fractions by vacuum distillation of crude oil and depressurization passages by depressurization of decompression distillation residue of crude oil, And a solvent extraction step of extracting the solvent with a solvent having selective affinity to the solvent, wherein the extracting process is carried out so that the polycyclic aromatic compound content of the extract as determined by the IP346 method is less than 3% by mass and the aniline point is 80 ° C or less Of the rubber process oil is determined.

In addition, the extract preferably has low carcinogenicity by PCA as described above, but it is also preferable that the mutagenicity index MI is less than 1.0. Of course, it is more preferable that the PCA is less than 3 mass% and the mutagenicity index MI is less than 1.0. It is further preferable that the PCA is less than 3 mass% and the mutagenicity index MI is less than 0.4.

The mutagenicity index MI is defined as the "Standard Test Method for Determining the Carcinogenic Potential of Virgin Base Oils in Metalworking Fluids " as defined in ASTM-E-1687-10. Quot; MI "

The production method of the extracutaneous index MI of less than 1.0 is not particularly limited, but for example, the process oil is disclosed in Japanese Patent No. 3624646.

In addition, the extract preferably has a content of benzo [a] pyrene (BaP) of 1 mg / kg or less and a specific aromatic compound (PAH) of 10 mg / kg or less because there is no concern about carcinogenicity. Here, the specific aromatic compound (PAH) means the aromatic compound (PAH) of the following 1) to 8).

1) benzo [a] pyrene (BaP)

2) benzo [e] pyrene (BeP)

3) benzo [a] anthracene (BaA)

4) Chrysene (CHR)

5) benzo [b] fluoranthene (BbFA)

6) benzo [j] fluoranthene (BjFA)

7) benzo [k] fluoranthene (BkFA)

8) benzo [a, h] anthracene (DBAhA)

In addition, these specific aromatic compounds can be quantitatively analyzed by GC-MS analysis after preparing a sample to which an internal standard substance is added after separating and concentrating the target component.

The production method of the extract having a benzo [a] pyrene (BaP) content of 1 mg / kg or less and a specific aromatic compound (PAH) of 10 mg / kg or less is not limited, No. -229314 has a% C _a is in accordance with ASTM D3238 25 ~ 45, benzo [a] is below the 1mg / kg content of pyrene (BaP), certain aromatic compounds (PAH) the production of Extract more than 10mg / kg Method is disclosed.

In addition, the extract preferably has a concentration of bay proton (% H _Bay ) of less than 0.35%. Here, the term "bair protons" refers to the ratio of hydrogen atoms in a portion called "Bay region" surrounded by a condensed benzene ring by ¹ H-NMR to determine the carcinogenicity according to the structure of the aromatic compound. The measuring method is ISO 21461 " Rubber-Determination of the aromaticity of the oil in vulcanized rubber compound ". It is known that the higher the concentration of the bayer proton is, the higher the carcinogenicity, and it is preferably less than 0.35%.

The extract has a benzo (a) pyrene (BaP) content of 1 mg / kg or less, a specific aromatic compound (PAH) of 10 mg / kg or less, a bayonet concentration (% H _Bay ) of less than 0.35% It is particularly preferable that the index MI is less than 1.0.

In addition, the extract may have insufficient solubility if% C _A (ASTM D2140) is less than 15%. On the other hand, when% C _A (ASTM D2140) of extract is more than 50%, it is not preferable to make the extraction amount of DMSO less than 3% remarkably and the economical efficiency of the purification process deteriorates.

The extract preferably has an aniline point of 90 DEG C or lower. If the aniline point of the extract is higher than 90 캜, the solubility is lowered.

In addition, when the extract has an aromatic content of less than 60% by column chromatography, the solubility may be lowered. On the other hand, when the aromatic content of the extract by column chromatography exceeds 95%, it is not preferable to make the DMSO extraction content less than 3% remarkably difficult and the economical efficiency of the purification process deteriorates.

On the other hand, there is no particular limitation on the production method of the base oil classified into Group I in the classification according to the base oil classification according to the API (American Petroleum Institute), but generally, the atmospheric distillation residue obtained by atmospheric distillation of crude oil is further distilled under reduced pressure, Is also produced by extracting the oil and purifying it.

The blending amount of the above base oil (A-2) is preferably 4% by mass or more, more preferably 5% by mass or more, still more preferably 5.5% by mass or more, and preferably 55% % Or less, more preferably 50 mass% or less, still more preferably 30 mass% or less.

In the lubricating oil composition of the present invention, the kinematic viscosity at 100 캜 of the base oil (A) containing the base oil (A-1) and the base oil (A-2) is in the range of 8.5 to 12.6 mm 2 / s, preferably 10.0 to 12.3 Mm < 2 > / s, and even more preferably in the range of 11.0 to 12.0 mm < 2 > / s. If the kinematic viscosity of the base oil at 100 DEG C is less than 8.5 mm < 2 > / s, the formation of the oil film at the lubricating portion is insufficient, and the lubricity is lowered and the evaporation loss of the base oil may increase. If the kinematic viscosity of the base oil at 100 DEG C exceeds 12.6 mm < 2 > / s, there is a concern that the low temperature fluidity will be a problem.

In the lubricating oil composition of the present invention, the aromatic content of the base oil (A) containing the base oil (A-1) and the base oil (A-2) is not less than 1.05 mass%, preferably not less than 1.10 mass% Is not less than 1.15% by mass and not particularly limited, but preferably not more than 10% by mass. When the aromatic content of the base oil (A) is not less than 1.05 mass%, the high temperature cleanliness and caking resistance (heat resistance) of the lubricating oil composition can not be sufficiently improved. In the present invention, the aromatic content or the total aromatic content, the one-ring aromatic content, and the two-ring aromatic content of the base oil (A) in three or more rings means a value measured by a high-performance liquid chromatography method.

The base oil (A) of the lubricating oil composition of the present invention preferably has a viscosity index of 80 or more, more preferably 85 or more, and particularly preferably 90 or more. If the viscosity index of the base oil is less than 80, the viscosity at low temperature may increase and the starting performance may deteriorate. In the present invention, the viscosity index means a viscosity index measured according to JIS K2283-1993.

The lubricating oil composition for a crosshead type diesel engine system of the present invention contains a metallic detergent (B) as an essential component.

As the metal cleaner (B), any compound commonly used in lubricating oil can be used, and examples thereof include sulfonate cleaners, phenate cleaners and salicylate cleaners, among which salicylate And a salicylate-based detergent of Ca salt (i.e., Ca salicylate) is particularly preferable. When used, these metallic detergents may be used alone or in combination of two or more.

As the sulfonate-based detergent, for example, an alkaline earth metal salt of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a weight average molecular weight of 400 to 1500, preferably 700 to 1300, or its basic salt can be used have. Examples of the alkaline earth metals include 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 the petroleum sulfonic acid used herein include sulfonated alkylaromatics of lubricating oil fractions of mineral oil, and so-called mahogany acids, which are by-produced in the production of white oil. Examples of the synthetic sulfonic acid include sulfonated alkylbenzene having a linear or branched alkyl group obtained by by-product in an alkylbenzene production plant as a raw material of detergent or by alkylating a polyolefin with benzene, or a sulfonated sulfonic acid such as dinonylnaphthalene Or the like can be used. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid and anhydrous sulfuric acid are usually used.

As the phenate cleaner, an alkaline earth metal salt of alkylphenol sulfide or a basic salt thereof having a structure represented by the following general formula (1) can be used. The alkaline earth metals include, for example, magnesium, barium and calcium, with magnesium or calcium being preferred, and calcium being particularly preferred.

[Chemical Formula 1]

In the general formula (1), R ¹ represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, m represents an integer of 1 to 10 in terms of degree of polymerization, S represents a sulfur element and x represents an integer of 1 to 3 .

The alkyl group and the alkenyl group in the formula (1) preferably have a carbon number of 9 to 18, more preferably 9 to 15. When the number of carbon atoms is less than 6, solubility in the base oil may deteriorate. On the other hand, when the number of carbon atoms exceeds 21, the production is difficult and the heat resistance may deteriorate.

Among the phenate-based metal detergents, it is preferable that an alkylphenol sulfide metal salt having a degree of polymerization m shown in Chemical Formula 1 of not less than 4, particularly m is 4 to 5, is excellent in heat resistance.

The salicylate-based detergent is preferably a metal salicylate represented by the following general formula (2) and / or a basic salt thereof.

(2)

In the formula (2), R ² is independently an alkyl group or an alkenyl group, M is an alkaline earth metal, preferably calcium or magnesium, particularly preferably calcium, and n is 1 or 2.

The salicylate-based detergent is preferably salicylate of an alkaline earth metal having one alkyl or alkenyl group in the molecule and / or a basic salt thereof.

The method for producing the alkaline earth metal salicylate is not particularly limited and a known monoalkyl salicylate production method and the like can be used. For example, a method in which phenol is used as a starting material and alkylated using olefin Subsequently, a monoalkyl salicylic acid obtained by carboxymethylation of carbonic acid gas or the like, or a monoalkylsalicylic acid obtained by alkylation of salicylic acid with an equivalent amount of the above-mentioned olefin, or a metal base such as an oxide or hydroxide of an alkaline earth metal The alkaline earth metal salicylate can be obtained by reacting the alkaline earth metal salicylate with the alkaline earth metal salt or by once replacing the alkaline earth metal salt with an alkali metal salt such as a sodium salt or a potassium salt.

As the salicylate-based detergent, not only neutral salts obtained as described above but also basic salts obtained by heating these neutral salts and excess alkaline earth metal salts or alkaline earth metal bases (hydroxides or oxides of alkaline earth metals) in the presence of water Or an overbased salt obtained by reacting a neutral salt with a base such as a hydroxide of an alkaline earth metal in the presence of carbonic acid gas or boric acid or a borate salt.

The base weight of the metal detergent (B) is preferably in the range of 50 to 500 mgKOH / g, more preferably 100 to 450 mgKOH / g, and even more preferably 120 to 400 mgKOH / g. When the amount of the base is less than 50 mgKOH / g, there is a fear that the corrosion wear increases. On the other hand, when the base is more than 500 mgKOH / g, the solubility may be problematic.

The metal ratio of the metal detergent (B) is not particularly limited, but the lower limit is preferably 1 or more, more preferably 1.3 or more, particularly preferably 2.0 or more, and the upper limit is preferably 5.0 or less, more preferably 4.0 Or less, and particularly preferably 3.0 or less. Also, the term "water" x metal element content (mol%) / soap group content (mol%) of the metal element of the metal-Varian metal detergent (B) The metal element includes calcium and magnesium, and the soap group means a sulfonic acid group, a phenol group, a salicylic acid group and the like. As the metal element, calcium is preferable.

In the lubricating oil composition of the present invention, the metal-based detergent (B) may be used alone, or two or more thereof may be used in combination. (1) an overbased Ca phenate / neutral Ca sulfonate, (2) an overbased Ca phenate / overbased Ca salicylate, (3) an overbased Ca phenate / neutral Ca sulfonate / And a combination of any one of ordinary Ca salicylates is preferable.

In the lubricating oil composition of the present invention, the content of the metallic detergent (B) is preferably 1.5 to 31 mass%, more preferably 2.0 to 25 mass%, and particularly preferably 3.0 to 8.0 mass% to be. If the content of the metal-based cleaner (B) is less than 1.5% by mass, the required cleanliness and acid neutralization property may not be obtained. On the other hand, if it exceeds 30% by mass, there is a fear of emulsification in the centrifugal cleaner.

In the lubricating oil composition of the present invention, the content of the metal component based on the metal-based cleaner (B) component is preferably 0.14 to 0.72 mass%, more preferably 0.17 to 0.54 mass%, particularly preferably Is from 0.21 to 0.36 mass%. If the content of the metal component based on the metal-based cleaner (B) is less than 0.14 mass%, the required cleanliness and acid neutralization property may not be obtained. On the other hand, if the content exceeds 0.72 mass% Granulation) and may be sludged in a centrifugal separator.

Further, the system lubricating oil composition for a crosshead type diesel engine of the present invention contains zinc dithiophosphate (C) (ZnDTP) as an essential component.

The zinc dithiophosphate (C) is preferably a compound represented by the following formula (3).

(3)

In the above formula (3), each R ³ independently represents a hydrocarbon group having 1 to 24 carbon atoms, and the hydrocarbon group having 1 to 24 carbon atoms is preferably a linear or branched alkyl group having 1 to 24 carbon atoms. The hydrocarbon group preferably has 3 or more carbon atoms, more preferably 12 or less carbon atoms, and still more preferably 8 or less. The alkyl group may be a first class, a second class or a tertiary class, but a first class or a second class or a mixture thereof is preferable, and the second class is most preferable.

Examples of the zinc dithiophosphate (ZnDTP) include zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc diheptyldithiophosphate, or dioctyl Having a linear or branched (primary, secondary or tertiary, preferably primary or secondary) alkyl group having 3 to 18 carbon atoms, preferably 3 to 10 carbon atoms, such as zinc dithiophosphate, Zinc dialkyldithiophosphate; Di ((alkyl) aryl) dithiophosphate having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, such as zinc diphenyl dithiophosphate or zinc ditolyl dithiophosphate, or an alkyl And mixtures of two or more species.

The method for producing zinc dithiophosphate is not particularly limited. For example, by reacting an alcohol having an alkyl group corresponding to R ³ with a dihydric phosphorus to synthesize dithiophosphoric acid and neutralizing it with zinc oxide Can be synthesized.

In the lubricating oil composition of the present invention, the content of the zinc dithiophosphate (C) is preferably 0.25 to 1.4% by mass, more preferably 0.4 to 1.0% by mass, particularly preferably 0.5 to 0.7% by mass, Mass%. The zinc dithiophosphate (C) is preferably added so that the phosphorus content of the composition is 200 to 1000 mass ppm.

The lubricating oil composition of the present invention may further contain, in addition to the above components, any additives commonly used in lubricating oils for the purpose of further improving its performance or adding other required performance. Examples of such additives include antifoaming agents, ashless dispersants, pour point depressants, antioxidants, metal deactivators, extreme pressure agents, and the like.

Examples of the defoaming agent include silicone oils, alkenyl succinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long chain fatty acids, methyl salicylate and o-hydroxybenzyl alcohol, aluminum stearate, potassium oleate, N-dialkyl Aromatic amine salts of isoamyl octylphosphate, alkyl alkylene diphosphates, metal derivatives of thioethers, metal derivatives of disulfides, fluorine compounds of aliphatic hydrocarbons, triethylsilane, dichlorosilane, alkylphenyl polyethylene glycol Ether sulfide, fluoroalkyl ether, and the like. When the antifoaming agent is contained in the lubricating oil composition of the present invention, its content is usually selected in the range of 0.0005 to 1 mass% based on the total amount of the composition, and when the antifoaming agent contains silicon, the Si content of the composition is 5 to 50 mass ppm. < / RTI >

The ashless dispersant may be any ashless dispersant used in lubricating oil. For example, a nitrogen-containing compound having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms or an alkenyl group in its molecule or a derivative thereof . Examples of the nitrogen-containing nitrogen compound include succinic acid imide, benzylamine, polyamine, and Mannich bases. Examples of the derivatives thereof include boron compounds such as boric acid and borate, boron compounds such as (thio) phosphoric acid , Phosphorus compounds such as (thio) phosphate, organic acids, derivatives obtained by reacting hydroxy (poly) oxyalkylene carbonate, and the like. In the present invention, one kind or two kinds or more of them may be blended arbitrarily. In the present invention, the content of the ashless dispersant is 0 to 5% by mass, preferably 0.2 to 3% by mass, and more preferably 0.5 to 2% by mass, based on the total amount of the composition. When the content of the ashless dispersant is less than the above range, the sulfuric acid neutralization rate tends to be insufficient and the cleaning effect is not sufficient. In addition, if it exceeds the above range, not only the effect corresponding to the content can not be obtained but the water resistance is greatly deteriorated.

As the pour point depressing agent, for example, a polymethacrylate-based polymer suitable for the lubricating base oil to be used may be used. When the pour point depressant is contained in the lubricating oil composition of the present invention, its content is usually selected within the range of 0.005 to 5% by mass based on the total amount of the composition.

Examples of the antioxidant include antioxidants such as phenol-based and amine-based antioxidants, and metal antioxidants. Among them, an amine antioxidant is preferable from the viewpoint of maintenance of high-temperature clean performance. When an antioxidant is contained in the lubricating oil composition of the present invention, its content is usually 0.1 to 5% by mass, preferably 0.5 to 2% by mass, based on the total amount of the composition.

Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkyl thiadiazole, melphobenzothiazole, benzotriazole or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3 , 4-thiadiazole-2,5-bis dialkyldithiocarbamate, 2- (alkyldithio) benzoimidazole or? - (o-carboxybenzylthio) propionitrile. When the lubricating oil composition of the present invention contains a metal deactivator, its content is usually selected within the range of 0.005 to 1% by mass based on the total amount of the composition.

Examples of the extreme pressure agent include sulfur-based, phosphorus-based, sulfur-phosphorus-based extreme pressure agents, and specific examples thereof include phosphorous acid esters, thioalic acid esters, dithio phosphorous acid esters, trithiophosphoric acid esters, phosphoric acid esters There is provided a process for producing a polyisocyanate compound, which comprises reacting a polyisocyanate compound, a polyisocyanate compound, a polyisocyanate compound, a thiophosphoric acid ester, a dithiophosphoric acid ester, a trithiophosphoric acid ester, Sulfides, sulfides, polysulfides, sulfide olefins, sulfurized oils and the like. When the extreme pressure agent is used in the lubricating oil composition of the present invention, the content thereof is not particularly limited, but is usually 0.01 to 5% by mass based on the total amount of the composition.

The crosshead type diesel engine system lubricating oil composition of the present invention needs to have a kinetic viscosity required for a system lubricating oil composition for a crosshead type diesel engine and preferably has a kinematic viscosity at 100 DEG C of 8.2 mm2 / More preferably 10.5 mm 2 / s or higher, further preferably 12.6 mm 2 / s or lower, and still more preferably 12.0 mm 2 / s or lower. When the dynamic viscosity of the lubricating oil composition is less than 8.2 mm 2 / s at 100 ° C, the oil film forming ability is insufficient and the bearing may be burned. On the other hand, when the kinematic viscosity at 100 ° C is 12.6 mm 2 / There is a concern that burning of the piston may occur and the starting property may be deteriorated by the high viscosity.

The cross-head type diesel engine lubricating oil composition of the present invention needs to have a base content as a lubricating oil composition for a crosshead type diesel engine system lubricating oil composition. Specifically, the base is preferably 4 to 20 mg KOH / g (perchloric acid method) / g, more preferably from 6 to 10 mgKOH / g. When the base of the lubricating oil composition is less than 4 mgKOH / g, the cleanliness of the piston is insufficient. Also, when the base of the lubricating oil composition exceeds 20 mg KOH / g, it becomes difficult to remove the entrapped contaminants from the cleaner. In the present invention, the base value means the base weight by the perchloric acid method, which is measured according to JIS K2501 " Petroleum Products and Lubricant-Neutralization Value Test Method ".

The lubricating oil composition for a crosshead type diesel engine of the present invention has a phosphorus content of 200 to 1000 mass ppm, preferably 300 to 700 mass ppm, and more preferably 400 to 500 mass ppm. If the phosphorus content of the lubricating oil composition is less than 200 mass ppm, the gear performance is insufficient at PTO (Power Take-off). If the phosphorus content exceeds 1000 mass ppm, the hydrolysis product of ZnDTP and the detergent react with each other, There is a possibility that the value retainability is lowered.

Example

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

Examples 1 to 10 and Comparative Examples 1 to 9

The lubricating oil composition of the formulation shown in Table 1-2 was prepared and subjected to hot tube test according to JPI-5S-55-99. The results are shown in Tables 1 and 2. The amounts of the base oil in Tables 1 and 2 are based on the total base oil amount, while the amounts of the additives are based on the total amount of the composition. In addition, 0.1 part by mass of a pour point depressant (polymethacrylate) was added to each lubricating oil composition based on the total amount of the composition, and a defoaming agent (silicone oil) was added so that the Si content was 10 mass ppm.

≪ Hot tube test (I) >

Each test oil was subjected to a hot tube test at 290 ° C in accordance with JPI-5S-55-99, and 10 points (transparency = best) in the evaluation of the color density of the test tube discoloration portion after the test )]. The higher the rating, the better the high-temperature cleanliness. In Table 2, "clogging" indicates that the glass tube is clogged and the caking resistance is poor.

≪ Hot tube test (II) >

A hot tube test was conducted at 270 DEG C, 280 DEG C, and 290 DEG C in accordance with JPI-5S-55-99 using a mixed oil of 90 wt% of each test oil and 10 wt% of drip oil of cylinder oil. The drip oil of the cylinder oil used was taken from a crosshead type diesel engine mounted on a VLCC (Middle East to Japan). The properties of the diesel oil were as follows: kinematic viscosity at 100 ° C of 28.1 mm 2 / s, acid value of 7.5 mg KOH / g, (Perchloric acid method) of 24.1 mgKOH / g, and pentane insoluble matter (Method A) of 6.0% by mass.

The kinematic viscosity at 100 占 폚 = 5.568 mm2 / s, the sulfur content = 0.01 mass%, the saturated hydrocarbon content = 98.8 mass%, the total aromatic content Content = 0.8 mass%, one ring aromatic content = 0.7 mass%, two ring aromatic content = 0.1 mass%, three aromatic rings / aromatic content = 0 mass%

The kinematic viscosity at 100 DEG C = 10.74 mm < 2 > / s, the sulfur content = 0.01 mass%, the saturated hydrocarbon content = 98.9 mass%, the total aromatic Content = 0.9 mass%, one ring aromatic content = 0.7 mass%, two ring aromatic content = 0.15 mass%, three aromatic rings / aromatic content = 0.05 mass%

The kinematic viscosity at 100 DEG C = 31.7 mm < 2 > / s, the sulfur content = 0.52 mass%, the saturated hydrocarbon content = 46.30 mass Aromatic content = 53.30 mass%, 1 ring aromatic content = 40.03 mass%, 2 ring aromatic content = 10.66 mass%, 3 aromatic or more aromatic content = 2.61 mass%

Mineral oil base oil 4: kinematic viscosity at 100 占 폚 = 29.4 mm 2 / s, sulfur content = 0.00 mass%, saturated hydrocarbon content = 99.1 mass%, total aromatic Content = 0.7 mass%, one ring aromatic content = 0.53 mass%, two ring aromatic content = 0.18 mass%, three or more aromatic rings content = 0.04 mass%

Extract 1: High Viscosity Aromatic Extract, Kinematic Viscosity at 40 ° C = 1185 mm / s, Kinematic Viscosity at 100 ° C = 34.09 mm 2 / s, Sulfur Content = 3.78 Mass%, Saturated Hydrocarbon Content = 9.10 Mass%, Total Aromatic Content = 86.40 Mass%, one ring aromatic content = 36.55 mass%, two ring aromatic content = 31.36 mass%, three aromatic rings / aromatic content = 18.49 mass%

Extract 2: Low viscosity aromatic extract, kinematic viscosity at 40 캜 = 274.8 mm 2 / s, kinematic viscosity at 100 캜 = 14.81 mm 2 / s, sulfur content = 3.32 mass%, saturated hydrocarbon content = 16.90 mass%, total aromatic content = 79.10 mass%, 1 ring aromatic content = 44.06 mass%, 2 ring aromatic content = 25.63 mass%, 3 aromatic or more aromatic content = 9.41 mass%

Extract 3: Residual aromatic extract, kinematic viscosity at 40 ° C = 3650 mm 2 / s, kinematic viscosity at 100 ° C = 70 mm 2 / s, sulfur content = 3.86 mass%, saturated hydrocarbon content = 6.70 mass%, total aromatic content = 87.90 Mass%, one ring aromatic content = 27.95 mass%, two ring aromatic content = 35.60 mass%, three aromatic rings / aromatic content = 24.35 mass%

Phthalic acid ester: monocyclic aromatic compound, carbon number 13

Alkyl naphthalene: bicyclic aromatic compound

Ca salicylate: 170 mgKOH / g, Ca content = 6.0% by mass, metal ratio = 2.3

ZnDTP: primary, a compound represented by the above formula (3) wherein R ³ is a 2-ethylhexyl group, a P content = 7.4 mass%

From the results of Examples 1 to 10 and Comparative Examples 1 to 9, it was found that by using a base oil containing base oil (A-1) and base oil (A-2) and having an aromatic content of three or more rings of 1.05 mass% It can be seen that the high temperature cleanliness and the resistance to coking (heat resistance) of the lubricating oil composition in the case of incorporating the dripped oil of the lubricating oil composition can be improved.

From the results of Comparative Example 2-7, it was found that even if the base oil (A-1) and the base oil (A-2) were included, the coke resistance (heat resistance) of the lubricating oil composition was less than 1.05 mass% It can not be improved.

Further, in the results of Comparative Examples 4 and 5, it was found that even if the aromatic content of one ring aromatic group or aromatic group of two rings is high, the high temperature cleanliness and coking resistance (heat resistance) of the lubricating oil composition can not be improved when the aromatic content of three or more rings is less than 1.05 mass% Able to know.

From the results of Comparative Examples 8 and 9, it can be seen that even if the base oil (A-1) having kinematic viscosity at 100 ° C is 4.0 to 12.6 mm 2 / s and the aromatic content of the base oil is more than 1.05 mass% (Heat resistance) of the lubricating oil composition can not be improved unless the base oil (A-2) having a kinematic viscosity of 16.3 to 60 mm 2 / s is included.

(A-1) having a kinematic viscosity at 100 DEG C of 4.0 to 12.6 mm < 2 > / s and a base oil (A) having a kinetic viscosity at 100 DEG C of 16.3 to 60 mm < 2 > / s and a saturated hydrocarbon content of less than 90 mass% (A) having a kinematic viscosity at 100 DEG C of 8.5 to 12.6 mm < 2 > / s and having an aromatic content of at least 3 rings of 1.05 mass% or more, Lt; RTI ID = 0.0 > oil). ≪ / RTI >

Claims (5)

A base oil (A-1) having a kinematic viscosity at 100 DEG C of 4.0 to 12.6 mm < 2 > / s,
(A-2) having a kinematic viscosity at 100 占 폚 of 16.3 to 60 mm2 / s and a saturated hydrocarbon content of less than 90 mass%
(A) having a kinematic viscosity at 100 DEG C of 8.5 to 12.6 mm < 2 > / s and an aromatic content of 3 or more rings of 1.05 mass% or more,
A metal-based detergent (B)
Zinc dithiophosphate (C)
, ≪ / RTI >
A basic value of 4 to 20 mgKOH / g, and a phosphorus content of 200 to 1000 mass ppm.
The method according to claim 1,
Wherein the base oil (A-1) has a saturated hydrocarbon content of 90 mass% or more.
3. The method according to claim 1 or 2,
Wherein the base oil (A-1) is a Group II base oil and / or a Group III base oil.
4. The method according to any one of claims 1 to 3,
Wherein the base oil (A-2) is an extract which is a byproduct when the solvent is refined in the process of producing the mineral oil base oil base oil.
5. The method according to any one of claims 1 to 4,
Wherein the metal-based cleaner (B) is Ca salicylate.