JP2005113151A - Lubricant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diesel cylinder lubricant composition for ships, which is suitably used for both high- and low-sulfur fuels and has a total base number of ≥30, preferably ≥35 (ASTM D 2896-01). <P>SOLUTION: The diesel cylinder lubricant composition for ships has a total base number of ≥30 and comprises ≥40 mass% of an oil of lubricating viscosity, at least one cleaning agent prepared from at least two surfactants, preferably fenate and sulfonate surfactants, at least one boron-containing dispersing agent which provides ≥100 ppm boron and at least one zinc-containing antiwear additive, preferably zinc dihydrocarbyl dithiophosphate, which provides ≥230 ppm zinc, preferably ≥250 ppm zinc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to lubricant compositions, particularly marine diesel cylinder lubricant (MDCL) compositions. Marine diesel / cylinder lubricant compositions are totally destructive lubricants that provide a strong oil film between the cylinder liner and piston ring, and the acid formed by the combustion of sulfur compounds in the fuel. It is to be summed up.

Fuels used in diesel engines generally have a high sulfur content (eg, 3.5% or more sulfur), so that exhaust gases from diesel engines contain a large amount of sulfur oxides (SO _x ). Sulfur oxide also reacts with moisture present in the exhaust gas to form sulfuric acid that corrodes the engine. Accordingly, marine diesel / cylinder lubricant compositions include an overbased metal detergent to neutralize sulfuric acid. Commercial marine diesel / cylinder lubricant compositions generally have a total base number ("TBN") of 70 or greater (measured using ASTM D2896).
Due to environmental concerns, many areas such as coastal areas require the use of low sulfur content fuels, that is, fuels containing less than 1.00% by weight sulfur. In this case, the use of a marine diesel cylinder lubricant composition with a lower total base number, such as 40, is permitted. Therefore, the ship needs to carry two types of lubricant tanks.
US Pat. No. 4,842,755 discloses a marine diesel / cylinder lubricant having a base number of 60 or more. The composition comprises a borated ashless dispersant, one or more overbased metal compounds and a zinc dialkyldithiophosphate that provides 0.02 to 0.023 weight percent (200 to 230 ppm) zinc. See). Certain examples show that performance benefits in ring and liner wear are lost when the amount of zinc exceeds 230 ppm.

The object of the present invention is to provide a marine diesel / cylinder lubricant composition having a total base number of 30 or more, preferably 35 or more (ASTM D 2896-01), suitable for use with both high and low sulfur fuels. It is to be.
It is a further object of the present invention to provide a total base suitable for use with both high and low sulfur fuels while providing the degree of protection required for corrosive wear when using high sulfur fuels. It is to provide a marine diesel / cylinder lubricant composition having a number of 30 or more, preferably 35 or more (ASTM D 2896-01).

According to the present invention, the total number of bases measured according to ASTM D2896 is 30 or more, preferably 35 or more,
An oil having a lubricating viscosity of 40% by mass or more with respect to the total mass of the marine diesel / cylinder lubricant composition;
One or more detergents prepared from two or more surfactants, preferably phenate and sulfonate surfactants;
One or more boron-containing dispersants that provide 100 ppm or more of boron, and one or more zinc-containing antiwear additives that provide 230 ppm or more, preferably 250 ppm or more of zinc, preferably zinc dihydrocarbyl dithiophosphate,
A marine diesel / cylinder lubricant composition is provided.
Surprisingly, the inventors have reviewed the teachings of US Pat. No. 4,842,755, and in a marine diesel / cylinder lubricant composition containing a detergent prepared from two or more surfactants, more than 230 ppm. It has been found that the use of this zinc increases the protection against wear.
The present invention also provides a good degree of wear protection even when the total number of bases, such as 40, is used when marine diesel and cylinder lubricant compositions as defined above are used with high sulfur fuels. I also found it to be offered.
According to the present invention, there is also provided a method of operating a marine diesel engine comprising the step of using the marine diesel / cylinder lubricant composition defined above for engine lubrication.
The present invention also provides the use of a marine diesel and cylinder lubricant composition as defined above to reduce wear in marine diesel engines.

The lubricating viscosity oil (also referred to as lubricating oil) may be any oil that is suitable for lubricating marine engines. The lubricating oil may be 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 in which the refining process further breaks down the medium and heavy fractions in the presence of hydrogen at high 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 base oil 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 to the weight of the composition. “Bright stock” may be included which refers to a base oil that may be used with respect to less than 40% by weight, preferably less than 30% by weight, more preferably less than 20% by weight.
The marine diesel / cylinder lubricant composition is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more of the total mass of the marine diesel / cylinder lubricant composition. Contains oil of viscosity.

A detergent detergent containing two or more surfactants is an additive that reduces the formation of piston deposits, such as high temperature varnish and lacquer deposits, in the engine, has the property of neutralizing acids, A finely divided solid can be retained in the suspension. 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 excess base 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 comprises two or more surfactants, preferably at least phenate and sulfonate. The detergent is also referred to as a composite / hybrid detergent. The complex detergent preferably comprises 5% by weight or more phenate, more preferably 10% by weight or more phenate, based on the total weight of the detergent. The complex detergent preferably comprises 5% by weight or more sulfonate, more preferably 8% by weight or more sulfonate, based on the total weight of the detergent. The detergent preferably also includes a salicylate surfactant. The detergent preferably contains 5% by weight or more of salicylate, more preferably 10% by weight or more of salicylate, based on the total weight of the detergent. The amount of surfactant in the composite detergent can be determined by techniques such as chromatography, spectroscopy and / or titration known to those skilled in the art. The detergent may also include other surfactants such as thiophosphates, naphthenates, or oil soluble carboxylates. Surfactant groups are mixed during the overbasing step. The metal is an alkali metal or alkaline earth metal such as sodium, potassium, lithium, calcium and magnesium. Calcium is preferred.

Examples of complex detergents are described in WO 97/46643, WO 97/46644, WO 97/46645, WO 97/46646 and WO 97/46647.
Preferably, the detergent has a TBN of 250-500, more preferably 280-480, even more preferably 300-450.
The marine diesel / cylinder lubricant composition is preferably 2% by mass or more, preferably 5% by mass or more, and more preferably 8% by mass or more of the total mass of the marine diesel / cylinder lubricant composition. including.
Marine diesel cylinder lubricants may also include additional detergents such as calcium phenate detergent, calcium sulfate detergent or calcium salicylate detergent. Additional detergents may have a low TBN of less than 50, a moderate TBN of 50-150, or a high TBN of 150 or more. The marine diesel / cylinder lubricant composition preferably comprises 4% by weight or more, preferably 6% by weight or more of a further detergent, based on the total weight of the marine diesel / cylinder lubricant composition.

Dispersant Marine diesel cylinder lubricant compositions include one or more dispersants that provide 100 ppm or more of boron. The dispersant is an additive in the lubricant composition whose primary function in the cylinder lubricant is to promote acid neutralization by the detergent system.
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 borated succinimides such as borated polyisobutene succinic anhydride, and borated polyamine condensation products.
The marine diesel / cylinder lubricant composition preferably contains boron of 150 ppm or more, more preferably 200 ppm or more, based on the total mass of the marine diesel / cylinder lubricant composition.

Anti-wear additive The anti-wear additive provides 230 ppm or more, preferably 250 ppm or more of zinc, based on the total weight of the marine diesel / cylinder lubricant composition. The anti-wear additive preferably provides 275 ppm or more, more preferably 300 ppm or more, even more preferably 325 ppm or more, even more preferably 350 ppm or more, even more preferably 375 ppm or more, and most preferably 385 ppm or more.
Anti-wear additives usually form dihydrocarbyl dithiophosphate (DDPA) by reacting one or more alcohols or phenols with P ₂ S ₅ and then neutralize the formed DDPA with a zinc compound. It can be prepared according to known techniques. 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. To form the zinc salt, 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). Particularly preferred R and R ¹ are alkyl groups of 2 to 8 carbon atoms. 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.

Antioxidant Marine Diesel / Cylinder Lubricant Compositions can 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 marine diesel cylinder lubricant.
Other additives such as pour point depressants, antifoams, 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, as well as larger amounts of certain additives, may be allowed as desired.
The lubricant composition of the present invention includes defined individual components (ie, individual components) that may or may not be chemically identical before and after mixing.
The present invention will be illustrated by the following examples, but the present invention is not limited thereto.

Marine diesel cylinder lubricant compositions were prepared to have a TBN of 40 or 70. The lubricant composition includes an overbased complex calcium detergent including phenate and sulfonate surfactants, a 250 base calcium phenate, a borated dispersant, and an antiwear agent.
Bolnes test using a Bolnes crosshead engine (single-cylinder two-stroke engine, Bolnes 3DNL) is performed on a lubricant composition containing about 3.5% sulfur, and is stabilized with a scale. It was. The Bolnes engine speed was 500 times / minute with a lubricant feed rate of 1.00 g / kwh. Each lubricant composition was tested for 96 hours. The test conditions were set so that corrosive wear occurred on the cylinder liner at this time. Wear was measured in μ at a specific graduated location on the cylinder liner. The average value of wear is reported below. The lower the result, the less cylinder liner wear.

Table 1

  The above table clearly shows that when the detergent is prepared from two or more surfactants, even the use of marine diesel and cylinder lubricants containing 385 ppm or more of zinc results in less wear. It is particularly surprising that Example 5 with a TBN of 40 has less wear even with a fuel with a higher sulfur content than Comparative Example 1 with a TBN of 70.

Claims (10)

A marine diesel / cylinder lubricant composition having a total base number of 30 or more measured according to ASTM D2896,
An oil having a lubricating viscosity of 40% by mass or more,
One or more detergents prepared from two or more surfactants, preferably phenate and sulfonate surfactants;
One or more boron-containing dispersants that provide 100 ppm or more of boron, and one or more zinc-containing antiwear additives that provide 230 ppm or more, preferably 250 ppm or more of zinc, preferably zinc dihydrocarbyl dithiophosphate,
A marine diesel / cylinder lubricant composition comprising:   The marine diesel / cylinder lubricant composition according to claim 1, wherein the detergent comprises 5 mass% or more of phenate and 5 mass% or more of sulfonate with respect to the total mass of the detergent.   The marine diesel / cylinder lubricant composition according to claim 1 or 2, wherein the detergent further contains a salicylate surfactant, preferably 5% by mass or more of salicylate based on the total mass of the detergent.   The marine diesel / cylinder lubricant composition according to any one of claims 1 to 3, wherein the lubricant has a base number of 35 or more, preferably 40 or more or 60 or more.   The marine diesel / cylinder lubricant according to any one of claims 1 to 4, wherein the dispersant provides boron of 150 ppm or more, preferably 200 ppm or more, based on the total mass of the marine diesel / cylinder lubricant composition. Composition.   The anti-wear additive provides 275 ppm or more, preferably 300 ppm or more, even more preferably 325 ppm or more, even more preferably 350 ppm or more, even more preferably 375 ppm or more, most preferably 385 ppm or more. The marine diesel / cylinder lubricant composition according to any one of 5 above. The marine diesel / cylinder lubricant composition according to any one of claims 1 to 6, wherein the anti-wear additive is an oil-soluble salt of dihydrocarbyl dithiophosphoric acid 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.)   The marine diesel / cylinder lubricant composition according to any one of claims 1 to 7, further comprising an amine-based or phenol-based antioxidant.   9. A method of operating a marine diesel engine with a fuel having a sulfur content of 3.0% or more, preferably 3.5% or more, for smoothing the engine. A method comprising the step of using a marine diesel / cylinder lubricant composition according to claim 1.   The marine diesel according to any one of claims 1 to 8, preferably with a fuel having a sulfur content of 3.0% or more, preferably 3.5% or more, for reducing wear in marine diesel engines. -Use of cylinder lubricant composition.