JP2005133098A - Method for reducing deposit formation in centrifuge system in trunk piston diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for reducing deposit formation in a centrifuge system in a trunk piston diesel engine. <P>SOLUTION: The method for reducing deposit formation in the centrifuge system in a trunk piston diesel engine includes a step of lubricating the trunk piston diesel engine with a trunk piston diesel engine lubricant composition having a total base number of ≥40 mgKOH/g, as determined by ASTM D2896, and including ≥40 mass% oil of lubricating viscosity, at least one detergent preferably at least two detergents, and ≥1.5 mass% phenol based on the total amount of the lubricant composition (if the trunk piston diesel engine lubricant composition includes at least one phenate detergent, the trunk piston diesel engine lubricant composition includes ≥1.7 mass% preferably ≥1.9 mass% phenol). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for reducing the formation of deposits in a centrifugal system of a trunk piston diesel engine.

The cylindrical piston diesel engine is used for ocean power generation and rail traction, and has a rated speed of 300 to 1000 times / minute. In cylindrical piston diesel engines, a single lubricant composition is used for crankcase and cylinder lubrication. The main moving parts of the engine, i.e. the main large end bearings, the camshaft and the valve device are all lubricated by the pump circulation system. The cylinder liner is lubricated in part by splash lubrication and in part by oil from the circulation that circulates through the holes in the piston skirt to the cylinder wall by connecting rods and gudgeon pins.
Cylindrical piston diesel engines use a centrifuge system to remove contaminants such as soot or water from the lubricant composition, for example. Centrifugal systems rely on the use of sealants that are heavier than lubricants. The sealing medium is generally water. When the lubricant composition is passed through the centrifuge system, it comes into contact with water. Therefore, the lubricant needs to be able to shed water and remain stable in the presence of water. If the lubricant does not repel water, the water forms an emulsion in the lubricant and becomes a deposit that forms in the centrifuge system, preventing the centrifuge system from operating properly. The centrifuge system typically operates at less than 100 ° C, such as less than 95 ° C, for example 90 ° C.
The total base number (TBN) of the cylindrical piston diesel engine lubricant composition is 30-40. However, cylindrical piston diesel engines with very low oil consumption have been developed in recent years, and as a result, lubricant formulators have increased the total base number to, for example, 50-60. Unfortunately, this increase in total base number affects the ability of the lubricant composition to separate contamination due to the sealant used in the centrifuge system, resulting in the formation of deposits in the centrifuge system. The

  It is an object of the present invention to provide a method for reducing deposit formation in a centrifugal system of a cylindrical piston diesel engine.

According to the present invention, there is provided a method for reducing deposit formation in a centrifugal system of a cylindrical piston diesel engine, the method having a total base number measured by ASTM D2896 of 40 mg KOH / g or more,
An oil having a lubricating viscosity of 40% by mass or more,
One or more detergents, preferably two or more detergents, and 1.5% or more phenol by weight based on the total weight of the lubricant composition;
A cylindrical piston diesel engine lubricant composition (however, when the cylindrical piston diesel engine lubricant composition contains one or more phenate detergents, the cylindrical piston diesel engine lubricant composition is 1.7). A step of lubricating the cylindrical piston diesel engine with a mass% or more, preferably 1.9 mass% or more of phenol).
Phenol may be added separately to the cylindrical piston diesel engine lubricant composition and / or may be added as part of the detergent, for example as part of unreacted components present in the detergent. If phenol is part of the detergent, the amount of phenol present can be detected by one skilled in the art using methods such as titration and chromatography.
The cylindrical piston diesel engine lubricant composition preferably comprises a sulfurized or non-sulfurized alkylphenol.
The total base number of the cylindrical piston diesel engine lubricant composition is 50 mgKOH / g or more, preferably 70 mgKOH / g or less.
Surprisingly, the cylindrical piston diesel engine lubricant composition defined above is a sealant used in a centrifugal system of a cylindrical piston diesel engine even if the TBN is 40 mgKOH / g or more. It has been found that contamination by can be separated. Accordingly, such a cylindrical piston diesel engine lubricant composition has a longer service life than a cylindrical piston diesel engine lubricant composition that is insufficient to repel the sealant.
In accordance with the present invention, there is also provided the use of a cylindrical piston diesel engine lubricant composition as defined above to reduce deposit formation in a centrifugal piston diesel engine centrifuge.

Oil of lubricating viscosity Oil of lubricating viscosity (also referred to as lubricating oil) may be any oil that is suitable for lubricating a cylindrical piston diesel engine. The lubricating oil is suitable for animal oil, vegetable oil or mineral oil. Suitable lubricating oils are petroleum derived lubricating oils such as naphthenic base oils, paraffinic base oils or mixed base oils. Alternatively, the lubricating oil may be a synthetic lubricating oil. Suitable synthetic lubricating oils include synthetic ester lubricating oils including diesters such as dioctyl adipate, dioctyl sebacate and tridecyl adipate, or polymeric hydrocarbon lubricating oils such as liquid polyisobutene and poly alpha olefins. Usually mineral oil is used. The lubricating oil generally constitutes 60% by weight or more, typically 70% by weight or more of the composition, and typically has a kinematic viscosity at 100 ° C. of ² to 40 mm ² / sec, such as 3 to 15 mm ^2. The viscosity index is 80 to 100, for example 90 to 95, per second.
Another type of lubricating oil is a hydrocracked oil that is further cracked by the refining process into medium and heavy distillate fractions in the presence of hydrogen at elevated temperatures and moderate pressures. Hydrocracked oils typically have a kinematic viscosity at 100 ° C. of ² to 40 mm ² / sec, such as 3 to 15 mm ² / sec, and a viscosity index typically in the range of 100 to 110, such as 105 to 108. It is.
An oil is a product that has been solvent extracted from a vacuum residue, typically having a kinematic viscosity at 100 ° C. of 28-36 mm ² / sec, with asphalt removed, typically relative to the weight of the composition. "Brightstock" can be included to refer to base oils used in a proportion of less than 40% by weight, preferably less than 30% by weight, more preferably less than 20% by weight.
The cylindrical piston diesel engine lubricant composition preferably comprises an oil having a lubricating viscosity of 50% by weight or more, more preferably 60% by weight or more, and even more preferably 70% by weight or more based on the total weight of the lubricant composition. .

Detergents Detergents, deposits in the engine, for example, an additive that reduces the formation of high-temperature varnish and lacquer deposits, has the property of neutralizing acids, holds the finely divided solids in suspension Yes. It is based on a metal “soap” which is a metal salt of an acidic organic compound, also called a surfactant.
The detergent includes a polar head with a long hydrophobic tail. An overbase containing a detergent neutralized as an outer layer of a metal base (eg carbonate) micelle by reacting an excess of a metal compound such as an oxide or hydroxide with an acidic gas such as carbon dioxide A large amount of metal base is included by forming a sexual detergent.
The detergent is preferably an alkali metal or alkali such as an overbased oil soluble or oily acidic calcium, magnesium, sodium or barium salt of a surfactant selected from phenol, sulfonic acid, carboxylic acid, salicylic acid and naphthenic acid. Earth metal additive, overbasing is provided by oil-insoluble salts of metals such as carbonates, basic carbonates, acetates, formates, hydroxides or oxalates, and more stable by oil-soluble salts of surfactants It has become. The metal of the oil-soluble surfactant salt may be the same as or different from the metal of the oil-insoluble salt. Preferably, the metal is calcium in both oil-soluble and oil-insoluble salts.
The TBN of the detergent may be low, medium or high. That is, the value measured by ASTM D2896 may be less than 50 mgKOH / g, 50 to 150 mgKOH / g, or 150 mgKOH / g or more. Preferably, the TBN is moderate or high and is 50 TBN or more. More preferably, the TBN has a value measured by ASTM D2896 of 60 mgKOH / g or more, more preferably 100 mgKOH / g or more, more preferably 150 mgKOH / g or more, and 500 mgKOH / g or less, such as 350 mgKOH / g or less. .

Surfactants for overbased detergent surfactant systems preferably include hydrocarbyl groups as substituents on, for example, aromatic rings. As used herein, the term “hydrocarbyl” consists primarily of hydrogen and carbon atoms, and is bonded to the remainder of the molecule by carbon atoms at a rate insufficient to substantially degrade the properties of the hydrocarbon. Means a group that does not ignore the presence of other atoms or groups. The hydrocarbyl group in the surfactant used according to the invention is advantageously an aliphatic group, preferably an alkyl or alkylene group, in particular an alkyl group (which may be linear or branched). The total number of carbon atoms in the surfactant should be sufficient to at least provide the desired oil solubility.
The phenol used to prepare the detergent may not be sulfurized, but is preferably sulfurized phenol. Furthermore, as used herein, the term “phenol” refers to phenols containing one or more hydroxyl groups or fused aromatic rings (eg, alkyl catechol or alkyl naphthol, respectively) and phenols modified by chemical reaction. Such as alkylene bridged phenols and Mannich base condensed phenols, and saligenin type phenols (prepared by reaction of phenol and aldehyde under basic conditions).
Preferred phenols can be derived from the following formula:

（式中、Rはヒドロカルビル基を示し、yは１乃至４を示す。yが１より大きい場合には、ヒドロカルビル基は同種でも異種でもよい。）

(In the formula, R represents a hydrocarbyl group, and y represents 1 to 4. When y is larger than 1, the hydrocarbyl group may be the same or different.)

Phenols are often used in sulfurized form. The sulfurized hydrocarbyl phenol is typically represented by the following formula:

（式中、xは一般的には１乃至４を示す。２個以上のフェノール分子がS_xブリッジにより結合されてもよい。）

(In the formula, x generally represents 1 to 4. Two or more phenol molecules may be bound by an S _x bridge.)

In both of the aforementioned formulas, the hydrocarbyl group represented by R is advantageously an alkyl group containing 5 to 100, preferably 5 to 40, in particular 9 to 12 carbon atoms, and has suitable solubility in oil. In order to guarantee the average number of carbon atoms in all R groups is 9 or more. A preferred alkyl group is a nonyl (tripropylene) group.
In the following description, hydrocarbyl substituted phenol will be referred to as alkylphenol for convenience.
The sulfurizing agent used to prepare the sulfurized phenol or phenate is a compound or element that introduces a-(S) _x- (wherein x is generally 1 to about 4) bridging groups between the alkylphenol monomer groups. Any one is acceptable. Thus, the reaction can be carried out using elemental sulfur or a halide thereof, such as sulfur dichloride or more preferably sulfur monochloride. When elemental sulfur is used, the sulfurization reaction can be carried out by heating the alkylphenol compound to 50 to 250 ° C., preferably 100 ° C. or higher. Using elemental sulfur will typically yield a mixture of bridging groups-(S) _x- as described above. When sulfur halides are used, the sulfurization reaction can be carried out by treating the alkylphenol at -10 to 120 ° C, preferably 60 ° C or higher. The reaction may be carried out in the presence of a suitable diluent. The diluent advantageously comprises a substantially inert organic diluent such as mineral oil or alkane. In any event, the reaction is carried out for a time sufficient to react substantially. In general, it is preferred to use 0.1 to 5 moles of alkylphenolic material per unit equivalent of sulfurizing agent.
When elemental sulfur is used as the sulfiding agent, it is desirable to use a basic catalyst such as sodium hydroxide or an organic amine, preferably a heterocyclic amine (eg morpholine).
Details of the sulfiding method are known to those skilled in the art.

Regardless of the method of preparation, sulfurized alkylphenols useful for the preparation of overbased detergents generally include diluent and unreacted alkylphenol, generally 2 to 20 weights relative to the weight of the sulfurized alkylphenol. %, Preferably 4 to 14% by weight, most preferably 6 to 12% by weight of sulfur.
As mentioned above, the term “phenol” as used herein includes, for example, phenol modified by chemical reaction with aldehydes, and Mannich base condensed phenol.
Aldehydes that modify phenol include, for example, formaldehyde, propionaldehyde, and butyraldehyde. A preferred aldehyde is formaldehyde. Aldehyde-modified phenols suitable for use are described, for example, in US-A-5 259 967.
Mannich base condensed phenol is prepared by reaction of phenol, aldehyde and amine. Examples of suitable Mannich base condensed phenols are described in GB-A-2 121 432.
In general, phenols can contain substituents other than those described above, provided that they do not significantly reduce the properties of the phenolic surfactant. Examples of such substituents are methoxy groups and halogen atoms.
The salicylic acid used according to the present invention may or may not be sulfurized, may be chemically modified and / or may contain additional substituents such as those described above for phenols, for example. Methods similar to those described above can also be used to sulfidize hydrocarbyl-substituted salicylic acids, which are well known to those skilled in the art. Salicylic acid is typically prepared by carboxylating phenoxide by the Kolbe-Schmidt method, in which case it is generally obtained in a mixture with uncarboxylated phenol (usually in a diluent). I will.

Preferred substituents in the oil-soluble salicylic acid from which the overbased detergents according to the invention can be derived are those represented by R described above for phenols. In the alkyl-substituted salicylic acid, the alkyl group advantageously contains 5 to 100, preferably 9 to 30, in particular 14 to 20 carbon atoms.
The sulfonic acids used according to the invention are typically obtained from hydrocarbyl substitution, in particular alkyl-substituted aromatic hydrocarbons, eg from petroleum fractions by distillation and / or extraction or by alkylation of aromatic hydrocarbons. Obtained by sulfonation. Examples thereof include those obtained by alkylation of benzene, toluene, xylene, naphthalene, biphenyl or their halogen derivatives such as chlorobenzene, chlorotoluene or chloronaphthalene. Alkylation of aromatic hydrocarbons is carried out in the presence of a catalyst in the presence of a catalyst, alkylating agents having 3 to 100 or more carbon atoms, for example haloparaffins, olefins obtained by paraffin dehydrogenation, and polyolefins, for example ethylene. , Propylene, and / or butene polymers. The alkylaryl sulfonic acids usually contain from 7 to 100 or more carbon atoms. They preferably contain 16 to 80, or 12 to 40 carbon atoms per alkyl-substituted aromatic moiety, depending on the source obtained.
When these alkylaryl sulfonic acids are neutralized to provide sulfonates, hydrocarbon solvents and / or diluent oils, and accelerators and viscosity modifiers may also be included in the reaction mixture.
Another type of sulfonic acid that can be used in accordance with the present invention includes alkylphenol sulfonic acids. Such sulfonic acids can be sulfurized. Whether sulphided or not, these sulfonic acids are said to have properties comparable to those of sulfonic acid surfactants, rather than those of phenolic surfactants.
Suitable sulfonic acids for use in accordance with the present invention also include alkyl sulfonic acids such as alkenyl sulfonic acids. In such compounds, the alkyl group suitably contains 9 to 100 carbon atoms, advantageously 12 to 80 carbon atoms, in particular 16 to 60 carbon atoms.

Carboxylic acids that can be used according to the present invention include mono- and dicarboxylic acids. Preferred monocarboxylic acids are those containing 1 to 30, especially 8 to 24 carbon atoms. (When this specification indicates the number of carbon atoms in the carboxylic acid, the number of carbon atoms in the carboxyl group is included in the number.) Examples of monocarboxylic acids include isooctanoic acid, stearic acid, oleic acid, palmitic acid, and Behenic acid. If desired, isooctanoic acid can be used in the form of a mixture of C ₈ acid isomers commercially available from Exxon Chemicals under the trade name “Cekanoic”. Other suitable acids are those that are tertiary substituted at the α-carbon atom and dicarboxylic acids having two or more carbon atoms that separate the carboxyl groups. Furthermore, dicarboxylic acids having 35 or more, for example 36 to 100 carbon atoms are also suitable. Unsaturated carboxylic acids can be sulfurized. Although salicylic acid contains a carboxyl group, for the purposes of the present invention, it is considered a separate group from the surfactant and is not considered a carboxylic acid surfactant. (Although it also contains hydroxyl groups, it is not considered a phenol surfactant.)
Examples of other surfactants that can be used in accordance with the present invention include the following compounds and derivatives thereof. Naphthenic acids, especially naphthenic acids containing one or more alkyl groups, dialkyl phosphoric acids, dialkylthiophosphoric acids, and dialkyldithiophosphoric acids, high molecular weight (preferably ethoxylated) alcohols, dithiocarbamic acids, thiophosphines, and dispersants. These types of surfactants are known to those skilled in the art. Hydrocarbyl-substituted carboxyalkylene-linked phenol type surfactants, dihydrocarbyl esters of alkylene dicarboxylic acids in which the alkylene group is substituted with a hydroxy group and an additional carboxylic acid group, or hydrocarbyl-substituted phenols with one or more aromatic moieties And alkylene-linked polyaromatic molecules containing one or more carboxyphenols are also suitable for use in the present invention. Such surfactants are described in EP-A-708 171.
Further examples of detergents useful in the present invention are optionally sulfurized modified with carboxylic acids such as stearic acid, as described for example in EP-A-271 262 (LZ-Adibis). Alkaline earth metal hydrocarbyl phenates, and phenates as described in EP-A-750 659 (Chevron).

Surfactants such as phenols, sulfonic acids, carboxylic acids, salicylic acids and naphthenic acids obtained by the production of overbased compounds, preferably hybrid materials in which two or more different surfactant groups are incorporated in the overbasing step Overbased calcium detergents containing two or more agent groups are also suitable for use in the present invention.
Examples of hybrid materials include surfactant phenol and sulfonic acid overbased calcium salts, surfactant phenol and carboxylic acid overbased calcium salts, surfactant phenol, sulfonic acid and salicylic acid overbased calcium salts, And overbased calcium salts of surfactants phenol and salicylic acid.
Where two or more overbased compounds are present, any suitable proportion (mass) may be used, but preferably any overbased metal of any other overbased metal compound The mass ratio to the compound is 95: 5 to 5:95, for example 90:10 to 10:90, more preferably 80:20 to 20:80, in particular 70:30 to 30:70, 60:40 to 40 : 60 is advantageous.
The hybrid detergent preferably comprises 5% by weight or more of salicylate, more preferably 10% by weight or more. The hybrid detergent preferably comprises 5% by weight or more of phenate. The amount of salicylate and phenate in the hybrid detergent may be determined using techniques such as chromatography, spectroscopy and / or titration known to those skilled in the art. The hybrid detergent may also include other surfactants such as sulfonates, sulfurized phenates, thiophosphates, naphthenates, or oil-soluble carboxylates. Surfactant groups are mixed during the overbasing step.
Specific examples of hybrid materials include, for example, WO-A-97 / 46643, WO-A-97 / 46644, WO-A-97 / 46645, WO-A-97 / 46646, And those described in WO-A-97 / 4664736.

By “surfactant overbased calcium salt” is meant an overbased detergent in which the metal cation of the oil-insoluble metal salt is substantially a calcium cation. A small amount of other cations may be present in the oil-insoluble metal salt, but typically more than 80 mol%, more typically more than 90 mol%, such as more than 95 mol% of the cations in the oil-insoluble metal salt are calcium. Ion. Cations other than calcium can be derived, for example, from using surfactant salts in the manufacture of overbased detergents where the cation is a metal other than calcium. Preferably, the metal salt of the surfactant is also calcium.
Preferably, the TBN measured by the hybrid detergent ASTM D2896 is 300 mg KOH / g or more, such as 330 mg KOH / g or more, more preferably 350 mg KOH / g or more, more preferably 400 mg KOH / g or more, most preferably 500 mg KOH / g. 400 to 600 mg KOH / g as follows.
Preferably, the amount of overbased metal detergent in the lubricant is 0.5% by weight or more, preferably 5 to 50% by weight, more preferably 10 to 50% by weight, based on the total weight of the lubricant composition. It is.
Overbased metal detergents may or may not be borated, but it is typically believed that boron-providing compounds such as metal borates form part of the overbasing. The detergent can include both non-borated detergents and borated detergents.
The overbased metal detergent preferably has a sulfated ash content (measured by ASTM D874) of 0.85% or more, more preferably 1.0% or more, and even more preferably 1.2% or more.
One or more detergents include phenol as an unreacted component, in which case the amount of phenol contributes to the total phenol content present in the cylindrical piston diesel engine lubricant composition. In some cases, the phenol present in the cylindrical piston diesel engine lubricant composition may all originate from one or more detergents.

The phenol cylindrical piston diesel engine lubricant composition contains 1.5% by weight or more, preferably 1.7% by weight or more, more preferably 1.9% by weight or more of phenol based on the total weight of the lubricant composition. Is included. More preferably, the cylindrical piston diesel engine lubricant composition is 2.0% by weight or more, even more preferably 2.1% by weight or more, and most preferably 2.2% by weight relative to the total weight of the lubricant composition. More than mass% phenol is included. When the cylindrical piston diesel engine lubricant composition includes one or more phenate detergents, the cylindrical piston diesel engine lubricant composition has 1.7% by weight based on the total weight of the lubricant composition. Above, preferably 1.9% by weight or more, more preferably 2.0% by weight or more, still more preferably 2.2% by weight or more, most preferably 2.4% by weight or more of phenol is contained.
The phenol may be added separately to the cylindrical piston diesel engine lubricant composition and / or may be added as part of the detergent, usually as an unreacted component.
The phenol may or may not be sulfurized. As used herein, the term “phenol” refers to phenols containing one or more hydroxyl groups or fused aromatic rings (eg, alkyl catechol or alkyl naphthol, respectively) and phenols modified by chemical reaction, eg, Includes alkylene bridged phenols and Mannich base condensed phenols, and saligenin type phenols (produced by reaction of phenol and aldehyde under basic conditions).
Preferred phenols can be derived from the following formula:

（式中、Rはヒドロカルビル基を示し、yは１乃至４を示す。yが１より大きい場合には、ヒドロカルビル基は同種でも異種でもよい。Rは、好ましくは２乃至２０個の炭素原子を含む。）

(Wherein R represents a hydrocarbyl group and y represents 1 to 4. When y is greater than 1, the hydrocarbyl group may be the same or different. R preferably has 2 to 20 carbon atoms. Including)

Preferred phenols are nonylphenol, dodecylphenol, or C _14, C ₁₆ and C ₁₈ - is a mixture of alkyl phenols.
Phenols are often used in sulfurized form. The sulfurized hydrocarbylphenol can typically be represented by the following formula:

（式中、xは一般的には１乃至４を示す。２個以上のフェノール分子がS_xブリッジにより結合されていてもよい。Rは、好ましくは２乃至２０個の炭素原子を含む。）

(Wherein x generally represents 1 to 4. Two or more phenol molecules may be linked by an S _x bridge. R preferably contains 2 to 20 carbon atoms.)

As mentioned above, the term “phenol” as used herein includes, for example, phenol modified by chemical reaction with aldehydes, and Mannich base condensed phenol.
Aldehydes that modify phenol include, for example, formaldehyde, propionaldehyde, and butyraldehyde. A preferred aldehyde is formaldehyde. Aldehyde-modified phenols suitable for use are described, for example, in US-A-5 259 967.
Mannich base condensed phenol is prepared by reaction of phenol, aldehyde and amine. Examples of suitable Mannich base condensed phenols are described in GB-A-2 121 432.
In general, phenols can contain substituents other than those described above, provided that they do not significantly reduce the properties of the phenolic surfactant. Examples of such substituents are methoxy groups and halogen atoms.
The cylindrical piston diesel engine oil preferably also contains one or more dispersants, anti-wear additives or antioxidants.

The dispersant cylinder piston diesel engine lubricant composition may include one or more dispersants. Dispersants are additives in lubricant compositions whose primary function is to improve engine cleanliness.
A notable class of dispersants are “ashless” which means non-metallic organic materials that do not substantially form ash upon combustion, as opposed to materials called ash-forming materials because they contain metals. Ashless dispersants include long chain hydrocarbons with a polar head, the polarity being derived from inclusion of, for example, O, P or N atoms. Hydrocarbons are lipophilic groups that provide oil solubility, for example having 40 to 500 carbon atoms. Thus, the ashless dispersant comprises an oil-soluble polymeric hydrocarbon backbone having functional groups that can bind to the particles to be dispersed.
Examples of ashless dispersants are succinimides such as polyisobutene succinic anhydride, and polyamine condensation products with or without borate.
If present, the dispersant is preferably present at 0.5 to 5% by weight, based on the total weight of the lubricant composition.

The anti-wear additive cylindrical piston diesel engine lubricant composition may include one or more anti-wear additives. The anti-wear additive may be metallic or non-metallic, but is preferably the former.
A metal salt of dihydrocarbyl dithiophosphate is an example of an antiwear additive. The metal of the dihydrocarbyl dithiophosphate may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or copper. Zinc salts are preferred, preferably in the range of 0.1 to 1.5% by weight, preferably 0.5 to 1.3% by weight, based on the total weight of the lubricating oil composition. They are generally known by first forming dihydrocarbyl dithiophosphate (DDPA) by reacting one or more alcohols or phenols with P ₂ S ₅ and then neutralizing the formed DDPA with a zinc compound. Can be prepared according to For example, dithiophosphoric acid can be prepared by reacting a mixture of primary and secondary alcohols. Alternatively, a plurality of dithiophosphoric acids can be formed that contain both hydrocarbyl groups that are all secondary and carbyl groups that are all primary. For the formation of zinc salts, any basic or neutral zinc compound that is not an oxide is used, and hydroxides and carbonates are most commonly used. Commercial additives often contain excess zinc due to the use of excess basic zinc compounds in the neutralization reaction.
A preferred zinc dihydrocarbyl dithiophosphate is an oil-soluble salt of dihydrocarbyl dithiophosphate, which can be represented by the following formula:
[(RO) (R ¹ O) P (S) S] ₂ Zn
Wherein R and R ¹ are hydrocarbyl groups containing the same or different 1-18, preferably 2-12 carbon atoms, alkyl, alkenyl, aryl, arylalkyl, alkaryl and cycloaliphatic. Groups such as groups are included.) Alkyl groups of 2 to 8 carbon atoms are particularly preferred as R and R ¹ . Thus, for example, ethyl, n-propyl, 1-propyl, n-butyl, 1-butyl, sec-butyl, amyl, n-hexyl, 1-hexyl, n-octyl, decyl, dodecyl, octadecyl, 2 -Ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl. To be oil soluble, the total number of carbon atoms in dithiophosphoric acid (ie, in R and R ¹ ) will generally be 5 or greater. Thus, the zinc dihydrocarbyl dithiophosphate can comprise a zinc dialkyldithiophosphate.
If present, the antiwear additive is preferably present at 0.10 to 3.0 weight percent based on the total weight of the lubricant composition.

The antioxidant cylindrical piston diesel engine lubricant composition may include one or more antioxidants. The antioxidant may be amine-based or phenol-based. As examples of amines, mention may be made of secondary aromatic amines such as diarylamines, for example diphenylamines in which each phenyl group is alkyl-substituted with an alkyl group having 4 to 9 carbon atoms. As examples of antioxidants, mention may be made of hindered phenols including monophenols and bisphenols.
Preferably, if present, the antioxidant is supplied to the composition to an amount of 3% by weight or less based on the total weight of the cylindrical piston diesel engine lubricant composition.
Other additives such as pour point depressants, antifoaming agents, metal rust inhibitors, and / or demulsifiers can be supplied as needed.
The term “oil-soluble” or “oil-dispersible” as used herein does not necessarily indicate that the compound or additive can be dissolved, admixed or suspended in the oil in all proportions. However, these terms mean that they can be dissolved or stably dispersed in the oil to a sufficient extent to exhibit the intended effect in the environment in which the oil is used. Furthermore, additional mixing of other additives may allow mixing of larger amounts of certain additives as desired.
The lubricant composition of the present invention comprises defined individual (ie, individual) components that may or may not be chemically identical before and after mixing.
Although not essential, it is desirable to prepare a concentrate comprising one or more additive packages or additives that can be simultaneously added to an oil of lubricating viscosity to form a lubricating oil composition. Dissolution of the additive package in the lubricating oil is facilitated by the solvent and by mixing with gentle heating, but is not essential. The additive package is typically suitable in an appropriate amount to provide the desired concentration when mixed with a predetermined amount of lubricant base and / or to perform the intended function in the final formulation. It is mix | blended so that the additive of this may be included.
Thus, for example, 2.5 to 90% by weight, preferably 5 to 75% by weight, most preferably 8 to 60% by weight, of the additive active ingredient in the additive package, with the rest being based The additive may be mixed with a small amount of base oil or other miscible solvent along with other desirable additives to form an additive package that is an oil.
The final formulation typically contains about 5-40% by weight additive package with the remainder being base oil.
The present invention will be described with reference to the following examples, but the present invention is not limited thereto.

The following examples use a centrifuge water separation test that evaluates the ability of an oil to separate water from a prepared test mixture of oil and water. The test uses an Alfa Laval MAB103B 2.0 centrifuge coupled to a Watson Marlow peristaltic pump. The centrifuge is sealed with 2 liters of water. Measure the amount of deposit formed in the centrifuge during the test. The test is performed at 87 ° C. A pre-measured amount of water and test oil are mixed and passed through a centrifuge at a rate of 2 liters / minute. The test is carried out for one and a half hours and the mixture passes through the centrifuge about 10 times. Weigh the centrifuge before and after the test. In the case of insufficient cylindrical piston diesel engine lubricant compositions, a relatively large amount of deposits will result in the centrifuge system.
A cylindrical piston engine oil (TPEO) having a TBN of 30 to 50 was prepared. Centrifuge water shedding test was performed on TPEO. Details of TPEO and test results are shown in Table 1 below.

Table 1

As shown in Table 1, as the TPEO TBN increases from 30 to 50 (see Comparative Examples 1, 2 and 3), the amount of deposits formed also increases. Table 1 also shows that as the amount of alkylphenol increases (see Examples 1, 2 and 3), the amount of deposits can decrease.
In the following examples, TPEO contains a phenate detergent.

Table 2

Comparative Example 4 containing only 1.7% alkylphenol yields 270 g of deposit. Examples 4, 5, 6 and 7 show that as the amount of alkylphenol increases, the amount of deposits can decrease.
In the following examples, phenol is added as an unreacted component of the detergent.

Table 3

  Comparative Example 2 containing only 0.99% alkylphenol yields 109 g of deposit. Examples 8, 9, and 10 show that increasing the amount of alkylphenol by selecting a detergent that further includes an alkylphenol can dramatically reduce the amount of deposits.

Claims (11)

A method for reducing deposit formation in a centrifuge of a cylindrical piston diesel engine, wherein the total base number measured by ASTM D2896 is 40 mg KOH / g or more,
An oil having a lubricating viscosity of 40% by mass or more,
One or more detergents, preferably two or more detergents, and 1.5% or more phenol by weight based on the total weight of the lubricant composition;
A cylindrical piston diesel engine lubricant composition (however, when the cylindrical piston diesel engine lubricant composition contains one or more phenate detergents, the cylindrical piston diesel engine lubricant composition is 1.7). Said method comprising the step of lubricating the cylindrical piston diesel engine with a mass% or more, preferably 1.9 mass% or more of phenol.   The method of claim 1, wherein the phenol in the composition is an unreacted component of the detergent.   The method of claim 1, wherein the phenol in the composition is not an unreacted component of the detergent.   The method of claim 1, wherein a portion of the phenol in the composition is an unreacted component of the detergent and a portion of the phenol is not an unreacted component of the detergent. The method according to any one of claims 1 to 4, wherein the phenol is derived from the following formula.

(In the formula, R represents a hydrocarbyl group and y represents 1 to 4, but when y is greater than 1, the hydrocarbyl group may be the same or different.) The method according to any one of claims 1 to 5, wherein the phenol is represented by the following formula.

(In the formula, R represents a hydrocarbyl group and y represents 1 to 4, but when y is greater than 1, the hydrocarbyl group may be the same or different, and x is 1 to 4.)   The method according to any one of claims 1 to 6, wherein the total number of bases of the detergent is 60 mg KOH / g or more.   The method according to any one of claims 1 to 7, wherein the total number of bases of the composition is 45 mg KOH / g or more, preferably 50 mg KOH / g or more, preferably 70 mg KOH / g or less.   The method according to any one of claims 1 to 8, further comprising one or more dispersants, antiwear agents, antioxidants, pour point depressants, antifoaming agents and demulsifiers.   The method according to claim 1, wherein the sealant is water.   Use of a cylindrical piston diesel engine lubricant composition according to any of claims 1 to 10 for reducing deposit formation in a centrifugal system of a cylindrical piston diesel engine.