KR101890605B1 - Cylinder-lubricant composition for crosshead diesel engine - Google Patents

Abstract

The present invention relates to a crosshead type cylinder lubricant oil for a diesel engine which is capable of suppressing the amount of piston sediment even when there is no problem with fuel of any sulfur amount, for example, excessive alkali, in addition to the conventional performance such as heat resistance, cleanliness and abrasion resistance (B) an ashless dispersant and (C) a metal detergent, (B) the product of the number average molecular weight of the ashless dispersant (B) and the effective concentration of the ashless dispersant is 9000 or more, Wherein the metal-based cleaner (C) has an endothermic peak temperature of 460 占 폚 or less at a heating rate of 50 占 폚 / min as measured by DSC.

Description

Technical Field [0001] The present invention relates to a cross-head type lubricating oil composition for a diesel engine,

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

In a crosshead type diesel engine, cylinder oil is used to lubricate the cylinder and the piston, and system oil is used to lubricate and cool the other parts. Here, the cylinder oil is required to have a proper viscosity required for lubrication between the cylinder and the piston (piston ring), and a function for maintaining the required cleanliness so that the motion of the piston and the piston ring becomes appropriate. In addition, crosshead type diesel engines are subject to corrosion problems of the cylinders due to acidic components such as sulfuric acid produced by the fuel, because inherent sulfur fuel is commonly used because of its economical efficiency. To solve this problem, it is necessary to neutralize acidic components such as sulfuric acid produced in the cylinder oil and to prevent corrosion.

In recent years, the crosshead type diesel engine has been required to have a large cylinder diameter (for example, a bore size of 70 cm or more) and an increase in piston stroke (for example, an average piston speed of 8 m / s or more Super long The stroke Chemistry), since increase in the combustion pressure (e.g., a brake mean effective pressure (BMEP), and the increase in the tendency to progress more than 1.8MPa), the combustion pressure is raised to cause dew point of sulfuric acid, the sulfuric acid corrosion of the cylinder It has become a more likely occurrence situation. As a measure for preventing sulfuric acid corrosion, there is a case where the wall temperature of the cylinder is raised (for example, the cylinder wall temperature is 250 DEG C or higher), and in addition, the amount of lubricating oil fed into the cylinder is reduced The lubrication environment of the cylinder is becoming more severe.

Also, in recent years, due to environmental problems, the International Maritime Organization (IMO) has begun to regulate emissions of marine engines and to limit the sulfur level of fuels to reduce sulfur dioxide emissions. At present, it is obligatory to use a fuel having a sulfur content of not more than 4.5% by mass in a specific sulfur fuel in a general sea area, and a low sulfur fuel having a fuel sulfur content of 1% by mass or less must be used in a regulated sea area centered on the North Sea .

When using a proprietary sulfur fuel, it is necessary to use a cylinder oil of high alkali (generally 70 mg KOH / g) to neutralize the acid component produced by combustion, but in the case of using low sulfur fuel, low alkali (generally 40 mg KOH / g). ≪ / RTI > This is because if a low-sulfur fuel (sulfur content of 1% by mass or less) is used while using a cylinder oil having a high alkali (70 mg KOH / g), the excess alkali component of the cylinder oil becomes a solid ash in the top land of the piston And the cylinder liner is abraded to cause excessive wear. On the other hand, if a sulfur-containing fuel is used in the state of a low-alkali (40 mg KOH / g) cylinder oil, neutralization of sulfuric acid produced by the fuel is insufficient and abrasion by corrosion occurs.

As the regulated sea area is expected to increase in the future, it is expected that the frequency of replacing cylinder oil will increase with the replacement of fuel oil during voyage. In order to simplify this troublesome replacement operation, it is preferable to use, as the cylinder oil, a single cylinder oil which can correspond to both the high sulfur fuel and the low sulfur fuel.

On the other hand, gasification of fuel is also being studied. When the fuel is a gas, the amount of sulfur in the fuel is small and a cylinder oil having an alkali value of not less than 40 mg KOH / g is preferable from the viewpoint of ensuring cleanliness. In this case, however, the alkali becomes excessive even at 40 mg KOH / g. In order to stably operate the gas fuel engine, it is a problem to control accumulation of excess base component in the top land of the piston. Therefore, even when gas is used as the fuel, if there is no problem with the same cylinder oil as the liquid fuel, it is possible to reduce the cost as well as the complexity of the supply side.

In the conventional cylinder oil, base oils are mainly composed of a sulfonate-based metal-based detergent, which is an overbearing agent, and many of them are low-cost which maintains anti-corrosive properties. In recent years, salicylate, phenate, (Japanese Patent Application Laid-Open Nos. H09-17455 and H05-94532) disclose that various types of metallic detergents as main components and also contain an extreme pressure agent and a dispersant.

Japanese Patent Application Laid-Open No. 2002-275491 Japanese Patent Publication No. 2002-515933 Japanese Patent Publication No. 2002-501974 Japanese Unexamined Patent Publication No. 2002-500262 Japanese Patent Application Laid-Open No. 2002-241780

In view of the foregoing, it is an object of the present invention to provide a cross-head type lubricating oil for a cylinder of a diesel engine, which is excellent in heat resistance, cleanliness and abrasion resistance and has no problem in fuel of any sulfur content. For example, and to provide a cylinder lube oil for a crosshead type diesel engine in which the amount of deposit is suppressed.

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that when the product of the number average molecular weight and the blending amount of the ashless dispersant and the effective concentration is not less than a specific value and the endothermic peak temperature of the metal- Of the total amount of the lubricating oil composition for a crosshead type diesel engine cylinder lubricating oil composition can improve the above problems, and the present invention has been accomplished.

That is, the present invention relates to a lubricating oil composition comprising (A) a lubricant base oil, (B) an ashless dispersant and (C) a metallic detergent, wherein the product of the number average molecular weight and the amount of the ashless dispersant (B) ) The metal-based cleaner is a cylinder lubricating oil composition for a crosshead type diesel engine, characterized in that the endothermic peak temperature at a heating rate of 50 캜 / min as measured by DSC is 460 캜 or less.

The above-mentioned ashless dispersant according to (B) is a cylinder lubricant composition for a crosshead type diesel engine, which has a number average molecular weight of 2500 or more.

The present invention softens the ash of the cylinder oil deposited on the piston top land and makes it possible to easily break down to suppress the accumulation of deposits on the land portion and as a result high alkali is used as the cylinder oil, And more particularly to a cross-head type cylinder lubricant composition for a diesel engine that can be used in a gas fuel engine.

Fig. 1 is a photograph showing the height of the fired product (ash).

Hereinafter, the present invention will be described in detail. In the cross-head type cylinder lubricant composition for a diesel engine of the present invention (hereinafter, simply referred to as a lubricant composition), there is no particular limitation on the lubricant base oil (A), and a mineral base oil used in ordinary lubricating oil, And / or synthetic base oils may be used.

Specific examples of the mineral oil base oil include lubricating oil distillate obtained by vacuum distillation of an atmospheric residue obtained by atmospheric distillation of crude oil, solvent deasphalting, solvent extraction, hydrogenolysis, solvent degassing, catalytic dewaxing (GTL WAX, gas-to-liquid wax) produced by a wax isomerized mineral oil, a Fischer-Tropsch process or the like, And a lubricant base oil produced by the method of the present invention.

The total aromatic content of the mineral base oil is not particularly limited, but is preferably 40 mass% or less, and more preferably 30 mass% or less. The total aromatic content of the mineral oil base oil may be 0% by mass, but is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, and more preferably 20% Particularly preferred. When the total aromatic content of the base oil exceeds 40 mass%, the oxidation stability is deteriorated, which is not preferable.

The total aromatic content means the content of aromatic fraction measured in accordance with ASTM D2549. Usually, these aromatic oils include compounds having a hetero ring such as pyridine, quinoline, phenol, naphthol, etc., as well as alkylbenzene, alkylnaphthalene, anthracene, petanthrene, And the like.

The sulfur content in the mineral oil base oil is not particularly limited, but is preferably 1% by mass or less, more preferably 0.5% by mass or less. The sulfur content in the mineral oil base oil may be 0 mass%, but is preferably 0.1 mass% or more, and more preferably 0.2 mass% or more. The solubility of the additive can be sufficiently increased by the fact that the mineral oil base oil contains the sulfur content to some extent.

Specific examples of synthetic base oils include polybutene or its hydride; 1-octene oligomer, 1-decene oligomer and the like, or a hydride thereof, which is an oligomer having 8 to 14 carbon atoms; Diesters such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate and di-2-ethylhexyl sebacate; Polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelletate, pentaerythritol-2-ethylhexanoate and pentaerythritol pelletate; Copolymers of dicarboxylic acids such as dibutyl maleate and? -Olefins having 2 to 30 carbon atoms; Aromatic synthetic oils such as alkylnaphthalene, alkylbenzene and aromatic ester, and mixtures thereof. Among these, the synthetic base oil is most preferably an oligomer having 8 to 14 carbon atoms called polyalphaolefin, and its kinematic viscosity at 100 캜 is 4 to 150 mm 2 / s.

In the present invention, (A) a mineral oil base oil, a synthetic oil base oil or an arbitrary mixture of two or more base oils selected from them may be used as the lubricant base oil. For example, a mixture of at least one mineral oil base oil, at least one synthetic oil base oil, at least one mineral oil base oil, and at least one synthetic oil base oil may be mentioned.

The kinematic viscosity of the lubricating base oil to be used is not particularly limited, but the kinematic viscosity at 100 캜 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 . When the kinematic viscosity of the lubricating oil base oil at 100 캜 exceeds 50 mm 2 / s, the low temperature viscosity characteristics deteriorate. On the other hand, when the kinematic viscosity is less than 4 mm 2 / s, the oil film formation at lubricating portions is insufficient, , And the evaporation loss of the lubricating oil base oil becomes large.

In the lubricating oil composition of the present invention, it is preferable that the lubricating base oil contains a lubricating base oil having a kinematic viscosity at 100 占 폚 of less than 4 to 17 mm2 / s and / or a kinematic viscosity at 100 占 폚 of 17 to 150 mm2 / s. Examples of the lubricating base oil having a kinematic viscosity of less than 4 to 17 mm2 / s at 100 占 폚 include mineral oil base oils such as SAE 10 to 40 and synthetic base oils. The kinematic viscosity thereof is preferably 5.6 mm2 / s or more, Is not less than 9.3 mm 2 / s, preferably not more than 14 mm 2 / s, more preferably not more than 12.5 mm 2 / s. Examples of the lubricating oil base oil having a kinematic viscosity at 100 占 폚 of 17 to 50 mm2 / s include mineral oil base oils such as SAE 50 and bright stock and synthetic base oils. The kinematic viscosity thereof is preferably 20 Mm 2 / s or more, more preferably 25 mm 2 / s or more, preferably 40 mm 2 / s or less, and more preferably 35 mm 2 / s or less. Also, synthetic base oil is equivalent to a lubricating base oil having a kinematic viscosity at 100 DEG C of 50 to 150 mm2 / s.

The amount of evaporation loss of the lubricant base oil is preferably 20 mass% or less, more preferably 16 mass% or less, and particularly preferably 10 mass% or less as NOACK evaporation amount. When the NOACK evaporation amount of the lubricating oil base oil is more than 20 mass%, the evaporation loss of the lubricating oil becomes large, which causes an increase in viscosity and the like, which is not preferable. The NOACK evaporation amount referred to here is a measurement of the evaporation amount of the lubricating oil measured in accordance with ASTM D5800.

The viscosity index of the lubricating base oil to be used is not particularly limited, but the value thereof is preferably 80 or more, more preferably 90 or more, and further preferably 100 or more so that excellent viscosity characteristics from low temperature to high temperature can be obtained. There is no particular limitation on the upper limit of the viscosity index of the lubricating oil base oil. The upper limit of the viscosity index of the lubricating oil base oil is not particularly limited. The viscosity index of the paraffin, slack wax or GTL wax, , A complex ester type base oil or a HVI-PAO type base oil having a viscosity index of about 150 to 250 can be used. From the viewpoint of solubility and storage stability of the additive, the viscosity index is preferably 120 or less, more preferably 110 or less .

The cross-head type lubricating oil composition for a cylinder for a diesel engine of the present invention contains (B) an ashless dispersant (hereinafter sometimes referred to as component (B)) as an essential component.

As the component (B), any ashless dispersant that can be used for a lubricating oil can be used. For example, a linear or branched alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, A nitrogen compound or a derivative thereof, a Mannish dispersant, or a modified product of an alkenylsuccinimide. When it is used, it may be blended with one kind or two kinds or more selected arbitrarily.

If the carbon number of the alkyl group or the alkenyl group of the nitrogen-containing compound or its derivative is less than 40, the solubility in the lubricating oil composition may decrease. On the other hand, if the alkyl group or alkenyl group has a carbon number of more than 400, the low temperature fluidity of the lubricating oil composition of the present invention deteriorates There is a concern. The alkyl or alkenyl group may be linear or branched. Preferably, the alkyl group or alkenyl group is an olefinic oligomer such as propylene, 1-butene, or isobutylene, a branched alkyl group derived from an oligomer of ethylene and propylene, And an alkenyl group.

Examples of the component (B) include one or more compounds selected from the following components (B-1) to (B-3).

(B-1) succinic imide having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule or a derivative thereof,

(B-2) benzylamine or derivative thereof having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule,

(B-3) A polyamine or a derivative thereof having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule.

Examples of the component (B-1) include compounds represented by the following formula (1) or (2).

In the formula (1), R ¹ represents an alkyl 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 the formula (2), R ² and R ³ each individually represent an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and particularly preferably a polybutenyl group. And i represents an integer of 0 to 4, preferably 1 to 3.

The component (B-1) includes a so-called mono-type succinic acid imide represented by the formula (1) in which succinic anhydride is added to one end of the polyamine and a so- Type succinimide, but the composition of the present invention may contain any one of them or a mixture thereof.

The succinimide as the component (B-1) is not particularly limited, and examples thereof include alkyl succinic acid or alkenyl succinic acid obtained by reacting a compound having an alkyl group or an alkenyl group having 40 to 400 carbon atoms with maleic anhydride at 100 to 200 ° C. Can be obtained by reacting succinic acid with a polyamine. Examples of the polyamine include diethylene triamine, triethylene tetramine, tetraethylene pentaamine, and pentaethylene hexaamine.

Examples of the component (B-2) include compounds represented by the following formula (3).

In the formula (3), R ⁴ represents an alkyl 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 production method of the benzylamine as the component (B-2) is not particularly limited. For example, a polyolefin such as a propylene oligomer, a polybutene or an ethylene -? - olefin copolymer is reacted with phenol to obtain an alkylphenol, And a method in which a polyamine such as formaldehyde and diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine is reacted by the Mannich reaction.

Examples of the component (B-3) include a compound represented by the following formula (4).

R ⁵ -NH- (CH ₂ CH ₂ NH) _k -H (4)

In the formula (4), R ⁵ represents an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and k represents an integer of 1 to 5, preferably 2 to 4.

The production method of the polyamine as the component (B-3) is not particularly limited. For example, a polyolefin such as a propylene oligomer, a polybutene or an ethylene -olefin copolymer is chlorinated and then ammonia, ethylene diamine, Amine, triethylene tetraamine, tetraethylene pentaamine, or pentaethylene hexaamine.

Examples of the derivatives of the nitrogen-containing compounds exemplified as the component (B) include monocarboxylic acids such as fatty acids having 1 to 30 carbon atoms and oxalic acid, phthalic acid, trimellitic acid and pyromellitic acid, Or an anhydride thereof, or an ester compound, an alkylene oxide having 2 to 6 carbon atoms, or a hydroxy (poly) oxyalkylene carbonate to neutralize part or all of the remaining amine group and / or imine group, Modified compounds by amidated, so-called oxygenated organic compounds; A so-called boron-modified compound in which boric acid is added to the above-mentioned nitrogen-containing nitrogen compound to neutralize or amidate some or all of the remaining amino group and / or imino group; A so-called acid-modified compound in which phosphoric acid is allowed to act on the above-mentioned nitrogen-containing nitrogen compound to neutralize or amidate a part or all of the remaining amino group and / or imino group; A sulfur-modified compound in which a sulfur compound is added to the nitrogen-containing compound described above; And modified compounds obtained by combining two or more kinds of denaturation selected from denaturation with nitrogen-containing organic compounds, boron denaturation, phosphoric acid denaturation, and sulfur denaturation with the above-mentioned nitrogen-containing nitrogen compounds. Among these derivatives, a boric acid-modified compound of alkenylsuccinic acid imide, particularly a boric acid-modified compound of bis-type alkenylsuccinic acid imide, can be further improved in heat resistance by being used in combination with the above-mentioned component (A).

The content of the component (B) in the lubricating oil composition of the present invention is usually from 0.005 to 0.4% by mass, preferably from 0.01 to 0.2% by mass, more preferably from 0.01 to 0.1% by mass, And particularly preferably 0.02 to 0.05 mass%. When the boron-containing ashless dispersant is used as the component (B), 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, 0.9. The higher the B / N ratio, the better the abrasion resistance and the burn resistance. However, when the B / N ratio is more than 1, there is a concern about the stability. When the boron-containing ashless dispersant is used, the content of the boron-containing ashless dispersant is not particularly limited, but it is preferably 0.001 to 0.1% by mass, more preferably 0.005 to 0.05% by mass, particularly preferably 0.01 To 0.04 mass%.

In the lubricating oil composition of the present invention, the component (B) preferably has a boron content of at least 0.5% by mass, more preferably at least 1.0% by mass, more preferably at least 1.5% by mass, particularly preferably at least 1.8% by mass, It is most preferable that the ashless dispersant, in particular, the bis-type boron-containing succinic acid imide ashless dispersant is contained. The boron-containing ashless dispersant having a boron content of 0.5% by mass or more may contain 10 to 90% by mass, preferably 30 to 70% by mass of a rare oil such as mineral oil and synthetic oil, and its boron content Quot; means the boron content in a state containing rare earth oil.

In the present invention, the number average molecular weight (Mn) of the component (B) is measured by removing the dilute petroleum from the sample by rubber membrane separation and analyzing it with Gel Permeation Chromatography (GPC).

The procedures for discriminating dialysis of rubber membrane are as follows.

(i) About 5 g of the sample is collected in the rubber membrane.

(ii) Tie the rubber membrane in a thread and put a rubber film in the center of the extraction thimble.

(iii) Place the cylindrical paper in the Soxle extractor.

(iv) Place 100 ml of petroleum ether in a flat flask, and place a Soxhlet extractor on the flask.

(v) A flat flask portion is heated (70 DEG C) in a water bath and the Soxhlet extractor is cooled with an attached cooler.

(vi) Reflux for 2 days.

(vii) Transfer the dialysis residue in the rubber membrane to a beaker, and rub the rubber membrane attachment in a beaker with petroleum ether. Remove the petroleum ether by warming in a water bath, and obtain the rubber film residue.

(viii) Remove the petroleum ether of the dialyzed flasks in a flat flask by warming in a water bath to obtain a dialyzate of rubber membrane.

The analysis conditions of GPC are as follows.

Apparatus: Water Alliance 2695 (Waters Alliance 2695)

Column: Tosoh GMHHR-M (Tosoh GMHHR-M)

Mobile phase: tetrahydrofuran

Solvent dilution concentration of the sample: 1 mass% (solvent: tetrahydrofuran)

Temperature: 23 ° C

Flow rate: 1 ml / min

Sample volume: 100 μl

Detector: RI

Molecular weight: Polystyrene equivalent

In the present invention, the effective concentration of the ashless dispersant of the component (B) was determined from the results of the aforementioned rubber membrane dialysis fractionation. That is, the ratio of the mass remaining in the rubber film to the amount of the sample (about 5 g) first collected as the sample was set as the effective concentration.

In the present invention, it is necessary to blend the ashless dispersant (B) so that the product of the number average molecular weight (Mn) and the blending amount of the ashless dispersant and the effective concentration becomes 9000 or more. The product thereof is preferably 10,000 or more, more preferably 12,000 or more Preferably not less than 15,000, and most preferably not less than 20,000, but preferably not more than 50,000. When the product is less than 9,000, the ease of fracture of the sediments for the purpose of the present invention is not sufficient, not only the number of sediments increases, but also the adverse effect on wear is increased. Conversely, if the product exceeds 50,000, the viscosity becomes excessively high, the fluidity becomes insufficient, and the cause of the increase of the deposit.

The breakability of the sediment referred to herein is measured from the height of the product of the cylinder lubricant composition baked by a thermogravimetry analyzer (TGA). Specifically, a cylinder lubricating oil composition is collected and fired in a hermetic pan of a TGA (thermobalance) to measure the height of the sintered cylinder lubricating oil composition expanded from the hermetic fan as shown in Fig. 1, such as cupcake do. The higher the height is, the more easily it is possible to break if it is formed as a sediment. Details are described in the examples.

In the present invention, the number average molecular weight (Mn) of the ashless dispersant (B) is preferably 2,500 or more, more preferably 3,000 or more, still more preferably 4,000 or more, and most preferably 5,000 or more. When the number average molecular weight of the ashless dispersant is less than 2,500, the ease of breakage of the sediment for the purpose of the present invention is not sufficient, and not only the number of sediments increases, but also the adverse effect on wear is increased. Conversely, when the number average molecular weight of the ashless dispersant exceeds 10,000, the viscosity becomes excessively high, the fluidity becomes insufficient, and the cause of the increase in the amount of sediments.

In the present invention, the amount and effective concentration of the ashless dispersant (B) are not particularly limited as long as the product of the number average molecular weight (Mn) of the ashless dispersant and the effective concentration is 9000 or more. (The ratio of the mass remaining in the rubber film to the amount of the sample initially collected as a sample) is preferably in the range of 0.30 to 0.70, and the concentration of the ashless dispersant in the composition (the product of the blending amount and the effective concentration) Is preferably in the range of 0.9 to 14% by mass based on the total amount of the composition.

The cylinder lubricating oil composition for a crosshead type diesel engine of the present invention contains (C) a metal-based cleaner (hereinafter referred to as component (C)) as an essential component.

As the metal-based cleaner (C), any compound usually used for lubricating oil can be used, and examples thereof include sulfonate-based cleaners, phenate-based cleaners, salicylate-based cleaners and naphthenate-based cleaners. These metal detergents may be used alone or in combination of two or more.

As the sulfonate detergent, there can be used, for example, an alkali metal salt, an alkaline earth metal salt or a basic 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 have. 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 the petroleum sulfonic acid referred to herein include sulfonated alkylaromatic compounds of a lubricating oil distillate of mineral oil, and so-called mahogany acids produced as a by-product in the production of white oil. Examples of the synthetic sulfonic acid include sulfonated alkylbenzene having a straight chain or branched alkyl group obtained by alkylating a polyolefin with benzene, or a sulfonated alkylbenzene having a linear or branched alkyl group obtained by alkylating a polyolefin with benzene, Naphthalene, naphthalene, and nylnaphthalene may be used. The sulfonating agent for sulfonating these alkylaromatic compounds is not particularly limited, but fuming sulfuric acid or anhydrous sulfuric acid can be usually used.

As the phenate cleaner, an alkali metal salt, an alkaline earth metal salt, or a basic salt of an alkylphenol sulfide having a structure represented by the following formula (5) may be used. Examples of the alkali metal or alkaline earth metal salt include sodium, potassium, magnesium, barium and calcium. Magnesium or calcium is preferable, and calcium is particularly preferable.

In the formula (5), R ⁶ represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, m is an integer of 1 to 10 in terms of degree of polymerization, S is a sulfur element, Lt; / RTI >

The number of carbon atoms in the alkyl group and the alkenyl group in the formula (5) is preferably 9 to 18, more preferably 9 to 15. When the number of carbon atoms is less than 6, the solubility in the base oil may deteriorate. On the other hand, when the number of carbon atoms is more than 21, the production is difficult and the heat resistance may deteriorate.

Among the phenate-based metal detergents, those containing an alkylphenol sulfide metal salt having a degree of polymerization (m) of 4 or more, particularly m, of 4 to 5 as represented by the formula (5) are preferable because of excellent heat resistance.

Examples of the salicylate-based detergent include an alkali metal, alkaline earth metal salicylate or basic salt thereof having one hydrocarbon group having 1 to 19 carbon atoms, an alkali metal having one hydrocarbon group having 20 to 40 carbon atoms, Earth metal salicylate or a basic salt thereof, an alkali metal having two or more hydrocarbon groups of 1 to 40 carbon atoms, an alkaline earth metal salicylate or a basic salt thereof. These hydrocarbon groups may be the same or different. Among them, it is preferable to use an alkali metal, alkaline earth metal salicylate or a basic salt thereof having one hydrocarbon group having 8 to 19 carbon atoms in view of excellent low-temperature fluidity. 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.

The alkali level of the component (C) is preferably in the range of 50 to 500 mg KOH / g, more preferably in the range of 100 to 450 mg KOH / g, and more preferably in the range of 120 to 400 mg KOH / g. When the alkali content is less than 50 mg KOH / g, corrosion wear may increase. On the other hand, when the alkali value is more than 500 mg KOH / g, there is a possibility of causing a problem in solubility.

The metal ratio of the component (C) is not particularly limited, but it is preferably 1 or more, more preferably 2 or more, particularly preferably 2.5 or more, and the upper limit is preferably 20 or less, more preferably 19 or less, And particularly preferably 18 or less is preferably used. The metal ratio referred to here is represented by the ratio of the number of metal elements to the number of metal elements (mol%) / the content of soap groups (mol%) in the component (C). Examples of metal elements include calcium and magnesium, and soap groups include sulfonic acid groups, phenolic groups, and salicylic acid groups.

In the lubricating oil composition of the present invention, component (C) can be used alone, but two or more components are preferably used in combination. (2) an overbased Ca phenate / overbased Ca salicylate, (3) an overbased Ca phenate / overbased Ca sulphonate / perchloric acid sulphonate / Overbased Ca salicylate is preferred.

The preferred ratio of (1) an overbased Ca phenate / overbased Ca sulphonate or (2) an overbased Ca phenate / overbased Ca salicylate is 0.1 or more, more preferably 0.2 or more, , And most preferably 0.3 or more. If the ratio is less than 0.1, heat resistance deteriorates. The ratio is preferably 9 or less, more preferably 7 or less, and most preferably 5 or less. If the ratio exceeds 9, the height is not sufficient in the TGA firing test and the sediment in the piston top land is not sufficiently reduced.

(3) In the case of the overbased Ca phenate / overbased Ca sulphonate / overbased Ca salicylate, the ratio of the overbased Ca sulphonate to the overbased Ca salicylate to the overbased Ca-phenate is in the above ratio desirable. In this case, the weight ratio of the amount of the overbased Ca sulfonate / the amount of the overbased Ca salicylate is not limited, but is preferably 0.1 or more, more preferably 0.2 or more, and most preferably 0.3 or more. If the weight ratio is less than 0.1, there is a possibility that the sediment increases in the state exceeding 300 캜. The weight ratio is preferably 9 or less, more preferably 7 or less, and most preferably 5 or less. When the weight ratio exceeds 9, the cleanliness decreases.

The content of the component (C) in the lubricating oil composition of the present invention is preferably 3 to 30 mass%, more preferably 6 to 25 mass%, and particularly preferably 8 to 20 mass%, based on the total amount of the composition. If the content of the component (C) is less than 3 mass%, the required cleanliness and acid neutralization property may not be obtained. On the other hand, if the content exceeds 30 mass%, excessive metal components may be deposited on the piston have.

In the lubricating oil composition of the present invention, the content of the metal based on the component (C) is preferably 0.35 to 3.6 mass%, more preferably 1.0 to 2.9 mass%, and particularly preferably 1.4 to 2.7 mass% Mass%. If the content of the metal based on the component (C) is less than 0.7% by mass, the required cleanliness and acid neutralization property may not be obtained. On the other hand, when the content is more than 3.6% by mass, Excess ash may accumulate and cause bore polishing or scuffing of the liner.

The component (C) of the present invention needs to have an endothermic peak temperature measured by differential scanning calorimeter (DSC) of 460 ° C or less.

The measurement conditions of the DSC are as follows.

Apparatus: TA instrument DSC2920 (TA instrument DSC2920)

Sample collection fan: Hermetic fan

Sample collection amount: 30 mg

Atmosphere: nitrogen (flow rate: 50 ml / min)

Heating rate: 50 ° C / min

Endothermic peak temperature: The endothermic peak temperature after evaporation of the diluent oil of the additive

If the endothermic peak temperature exceeds 460 DEG C, the effect of softening sediments can not be sufficiently obtained. Of course, the absence of an endothermic peak between the endothermic peak accompanying evaporation of diluted oil and 460 캜 has no effect of softening sediments. On the other hand, the lower limit of the endothermic peak temperature of the metal-based cleaner (C) is not particularly limited, but is preferably 350 ° C or higher. In this case, there is a possibility that the compound becomes unstable and the heat resistance becomes insufficient.

The lubricating oil composition of the present invention preferably contains a sulfur-based extreme pressure agent as the other components. Examples of the sulfur-containing extreme pressure agent include dihydrocarbyl polysulfide, sulfurized fatty acid, sulfurized olefin, sulfurized ester, sulfurized oil, sulfurized mineral oil, thiazole compound, thiadiazole compound and alkylthiocarbamate compound have.

Further, the lubricating oil composition of the present invention preferably contains an organic molybdenum compound. Examples of the organic molybdenum compound include organic molybdenum compounds containing sulfur such as molybdenum dithiophosphate and molybdenum dithiocarbamate (MoCTC); Molybdenum compounds such as molybdenum compounds such as molybdenum dioxide and molybdenum trioxide, molybdates such as orthomolybdic acid, paramolybdic acid and (poly) molybdic acid sulfide, molybdates such as metal salts and ammonium salts of these molybdic acids, molybdenum disulfide, Molybdenum sulfide such as molybdenum disulfide, molybdenum disulfide and molybdenum polysulfide; metal salt or amine salt of molybdenum sulfide, molybdenum sulfide, molybdenum halide such as molybdenum chloride) and a sulfur-containing organic compound (for example, alkyl (thio) xanthate (Di (thio) hydrocarbyldithiosulfonate) disulfide, organic (poly) sulfide, sulfide ester) or other organic compounds (for example, thiadiazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbylthiazolam disulfide, bis ≪ / RTI > Or a complex of a sulfur-containing molybdenum compound such as molybdenum sulfide or molybdenum sulfide with an alkenylsuccinic acid imide.

Further, the lubricating oil composition of the present invention preferably contains zinc dimolybdate (hereinafter referred to as component (E)) as an abrasion preventing agent. Examples of zinc dimolybdate include zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc diheptyldibutylphosphate and zinc dioctyldithiophosphate. A dialkyldithioalkyl group 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, Zinc phosphate; Di ((alkyl) aryl) dithiophosphate having an aryl group or an alkylaryl group having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, such as zinc diphenyldithiophosphate or zinc ditolyldithiophosphate, And mixtures of two or more thereof.

In addition to the above components, the lubricating oil composition of the present invention may further contain any additive generally used in lubricating oils according to its purpose, in order to further improve its performance or to add other required performance. Examples of such an additive include an antioxidant, an ashless friction modifier, a corrosion inhibitor, a rust inhibitor, an anti-emulsifier, a metal deactivator, a defoaming agent, or a colorant.

Examples of the antioxidant include antioxidants such as phenol-based and amine-based antioxidants; Based antioxidants such as copper, molybdenum and the like. The proportion of these is generally 0.1 to 5% by mass based on the total amount of the composition.

Examples of the ashless friction modifiers include fatty acid esters, aliphatic amines, and fatty acid amides. The proportion of these is generally 0.1 to 5% by mass based on the total amount of the composition.

Examples of the corrosion inhibitor include benzotriazole-based, tolyltriazole-based, thiadiazole-based, and imidazole-based compounds.

Examples of the rust inhibitor include petroleum sulfonates, alkylbenzenesulfonates, dinonylnaphthalenesulfonates, alkenylsuccinic acid esters, and polyhydric alcohol esters.

Examples of the above-mentioned anti-emulsifier include polyalkyl glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkyl thiadiazole, mercaptobenzothiazole, benzotriazole or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4 (Thiodiazolyl-2,5-bis dialkyldithiocarbamate, 2- (alkyldithio) benzoimidazole, or? - (o-carboxybenzylthio) propionitrile.

Examples of the defoaming agent include silicone oils and alkenyl succinic acid derivatives having a kinematic viscosity of less than 0.1 to 100 mm < 2 > / s at 25 deg.

When these additives are contained in the lubricating oil composition of the present invention, the content thereof is generally selected in the range of 0.005 to 5 mass% based on the total composition and 0.0005 to 1 mass% of the antifoaming agent.

The cross-head type cylinder lubricant composition for a diesel engine of the present invention preferably has an alkali value of 10 mg KOH / g or more, more preferably 20 mg KOH / g or more, still more preferably 25 mg KOH / g or more, particularly preferably 40 mg More preferably not more than 85 mg KOH / g, still more preferably not more than 75 mg KOH / g. When the alkali value is less than 10 mg KOH / g, the cleanliness of the piston is insufficient. In addition, if the alkali content exceeds 100 mg KOH / g, excessive alkali, that is, the metal carbonate forms a deposit to cause abrasion or piston ring clogging.

Further, when either of the specific sulfur fuel and the low sulfur fuel is used, the alkali value is preferably 50 mg KOH / g or more, more preferably 60 mg KOH / g or more, still more preferably 70 mg KOH / g or more. When the alkali content is less than 50 mg KOH / g, the neutralizing ability of the acidic substance generated when the sulfur fuel is used is insufficient and the corrosion wear can not be controlled. The upper limit in this case is as described above.

When using only low-sulfur fuel or gaseous fuel, the alkali level is preferably 60 mg KOH / g or less, more preferably 50 mg KOH / g or less, still more preferably 45 mg KOH / g or less. When the alkali content exceeds 60 mg KOH / g, when using a low-sulfur fuel or a gaseous fuel, there is a high possibility that excessive alkali, that is, metal carbonate forms deposits, causing wear and piston ring clogging. The lower limit in this case is as described above.

Here, the specific sulfur fuel means a fuel containing a sulfur content of 3.5 mass% or more, and the low-sulfur fuel is a fuel having a sulfur content of less than 1.0 mass%. Fuel having a sulfur content of not less than 1 mass% and less than 3.5 mass% can be treated as either a sulfur-rich fuel or a sulfur-reduced fuel. The sulfur content of the gas is 0.1 mass% or less.

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 14, Comparative Examples 1 to 8]

The lubricating oil composition of the formulation shown in Table 1 was prepared, and the ease of disintegration of the sediments formed was measured by TGA as described above. The test conditions are as described above.

Apparatus: TA instrument TGA2950 (TA instrument TGA2950)

Sample collection fan: Hermetic fan

Sample collection amount: 30 mg

Atmosphere: nitrogen (flow rate: 50 ml / min)

Heating rate: 50 ° C / min

Ease of disintegration of sediments: Ash temperature after temperature rise from room temperature to 600 ° C and after reaching 600 ° C for 30 minutes

Fig.

The lubricating oil composition thus prepared was subjected to the WD300 engine test by Ricardo under the following conditions.

Apparatus: WD300 engine manufactured by Ricardo (number of cylinders: 1, displacement: 2.2L, piston bore: 135mm)

Axis mean effective pressure: 20bar

Rotation speed: 1200 rpm

Fuel: light oil (sulfur content less than 10ppm)

Coolant outlet temperature: 85 ℃

Lubricating oil temperature: 80 ℃

Piston top land evaluation method: The Merit rating of the Japanese Petroleum Institute Act (JPI-5S-15) (the higher the rating, the less accumulated sediment).

Base oil: The kinematic viscosity (100 캜) of the lubricating oil composition was adjusted to 20.0 to 21.0 mm 2 / s by changing the ratio of base oil to 44 to 69 parts by mass of solvent refining base oil SAE 30 and from 31 to 56 parts by mass of bright stock

* Solvent refining base oil SAE 30: Kinematic viscosity (40 캜) 94.33 mm 2 / s, Kinematic viscosity (100 캜) 10.79 mm 2 / s

** Bright stock: kinematic viscosity (40 ° C) 466.6 mm 2 / s, kinematic viscosity (100 ° C) 31.57 mm 2 / s

Asbestos dispersant 1: Polybutenyl succinic acid imide, Mn 2390 (effective concentration: 40 mass%, ratio of the mass remaining in the rubber film to the collected sample amount = 0.4), endothermic peak at 442 deg. C

Asbestos dispersant 2: Polybutenyl succinic acid imide, Mn 2660 (effective concentration 50 mass%, ratio of the mass remaining in the rubber film to the collected sample amount = 0.5), endothermic peak at 447 deg. C

Asbestos dispersant 3: Polybutenyl succinic acid imide, Mn 3180 (effective concentration 60% by mass, ratio of the mass remaining in the rubber film to the collected sample amount = 0.6), endothermic peak at 456 ° C

Asbestos dispersant 4: Polybutenyl succinic acid imide, Mn 4460 (effective concentration 50 mass%, ratio of the mass remaining in the rubber film to the collected sample amount = 0.5), endothermic peak at 442 deg. C

Asbestos dispersant 5: Polybutenyl succinic acid imide, Mn 4770 (effective concentration 60% by mass, ratio of the mass remaining in the rubber film to the collected sample amount = 0.6), endothermic peak at 450C

(Weight ratio of remaining mass in the mass% mass% mass ratio rubber film = 0.45), endothermic peak at DSC of 453 deg. C

Metal cleaner 1: High basic alkali calcium salicylate, alkali 320 mg KOH / g, endothermic peak temperature in DSC 403 DEG C

Metal cleaner 2: High basic calcium sulfonate, alkali 400 mg KOH / g, endothermic peak temperature in DSC 449 ° C

Metal cleaner 3: Highly basic calcium sulfonate, alkali 400 mg KOH / g, endothermic peak temperature in DSC 470 ° C

Metal cleaner 4: High basic calcium sulfate, alkali 400 mg KOH / g, endothermic peak temperature in DSC 481 캜

Metal cleaner 5: Highly basic calcium sulfonate, alkali 400 mg KOH / g, endothermic peak temperature in DSC 498 캜

Metal cleaner 6: Highly basic calcium sulfonate, alkali 400 mg KOH / g, endothermic peak temperature in DSC 512 ° C

Metal-based cleaner 7: Highly basic calcium phenate, alkali 150 mg KOH / g, endothermic peak temperature in DSC 484 ° C

As shown in Table 1, the ash height has a very good correlation with the rating of the piston top land by the Ricardo WD 300 engine test. That is, when the height of the ash exceeds 2mm, the score of the sediment exceeds 3.5, meaning that there is little deposition of sediments.

Thus, the cylinder lubricating oil composition of the examples had a high ash height and a high score of the piston top land. The cylinder lubricant composition of Comparative Examples 2 to 4, in which the product of the number average molecular weight and the blending amount of the ashless dispersant and the effective concentration was less than 9000, The cylinder lubricating oil compositions of Comparative Examples 5 to 8, which did not contain a metal-based cleaner having a peak temperature of 460 占 폚 or less, had a low ash height and a low rating of a piston top land.

Claims (2)

(A) a lubricant base oil, (B) an ashless dispersant and (C) a metallic detergent,
Wherein the product of the number average molecular weight and the blending amount of the ashless dispersant (B) and the effective concentration is 9000 or more and 50,000 or less,
The (B) ashless dispersant has a number average molecular weight of 5000 to 10000,
The concentration of the ashless dispersant (B) in the composition is 0.9 to 14 mass% based on the whole amount of the lubricating oil composition,
The metal-based cleaner (C) has an endothermic peak temperature of 350 ° C or higher and 460 ° C or lower at a heating rate of 50 ° C / min as measured by DSC,
The metal-based cleaning agent (C) is an overbased calcium salicylate or an overbased calcium sulfonate,
Wherein the content of the metal-based cleaner (C) is 3 to 30 mass% based on the whole amount of the lubricating oil composition. delete

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