JP2007154199A - Lubricant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant composition which maintains wear inhibition and simultaneously brings about the reduction of catalyst poisoning. <P>SOLUTION: This lubricant composition comprises the following components: (a) a main amount of an oil having a lubrication viscosity, (b) a lithium-containing cleaner, (c) a cleaner except the lithium-containing cleaner, (d) an antioxidant, (e) a dispersant, and (f) an abrasion-resistant additive, wherein the lubricant composition does not contain >0.1 mass% of lithium and >0.12 mass% of phosphorus. The lubricant composition comprises the following components: (a) a main amount of an oil having a lubrication viscosity, (b) a lithium-containing cleaner, (c) a cleaner except the lithium-containing cleaner, (d) an amine-containing antioxidant, (e) an ethylene carbonate treating dispersant, and (f) a phosphorus-containing abrasion-resistant additive, wherein the lubricant composition does not contain >0.1 mass% of lithium and >0.12 mass% of phosphorus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lubricating oil composition comprising the following components: (a) a major amount of oil of lubricating viscosity, (b) one or more lithium-containing detergents, and (c) one other than a lithium-containing detergent. Or two or more detergents, (d) one or more antioxidants, (e) one or more dispersants, and (f) one or more antiwear additives, The lubricating oil composition contains no lithium-containing detergent in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent. The present invention also relates to a lubricating oil composition comprising the following components: (a) a major amount of oil of lubricating viscosity, (b) a lithium-containing detergent, (c) a detergent other than a lithium-containing detergent, (D) an amine-containing antioxidant, (e) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive, provided that the lubricating oil composition comprises lithium in an amount greater than 0.1% by weight. And no amount of phosphorus greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent. The present invention also relates to a method for reducing catalyst poisoning in an exhaust gas aftertreatment device for an internal combustion engine, the method comprising operating the internal combustion engine using the lubricating oil composition of the present invention.

  Future diesel engines will be equipped with exhaust aftertreatment devices that allow them to comply with future exhaust gas legislation. Some of these devices have proven to be sensitive to the fuel and lubricant combustion products used in the engine. Some devices are sensitive to phosphorus from lubricants, other devices are sensitive to sulfur from both fuel and lubricants, and other devices are sensitive to sulfated ash from fuel and lubricant combustion. Sensitive. In order to guarantee the durability of these various types of aftertreatment devices, special lubricants characterized by low levels of sulfated ash, sulfur and phosphorus have been developed. The most common of these lubricants result in low sulfate ash levels with reduced sulfur and phosphorus. Less common are low phosphorus or phosphorus free lubricants that use certain, mostly sulfur or molybdenum based zinc dialkyldithiophosphate substitute additives.

  The guidelines for lubricants for low emission internal combustion engines commercialized in 2007 and 2008 are as follows: (1) Sulfated ash is equal to or equal to 1.0% by weight in diesel engine lubricants. Lower, must be less than or equal to 0.5% by weight for passenger car diesel engine lubricants. (2) Depending on the engine manufacturer, the sulfur content of the lubricant must not be less than 0.2% by weight. On the other hand, another engine manufacturer allows up to 0.4% by mass, and (3) some engine manufacturers have a maximum amount of phosphorus of 0.08% by mass. While other engine manufacturers accept phosphorus up to 0.12% by weight. The reduction in sulfated ash reduces the gap between diesel engine lubricants and gasoline and natural gas engine lubricants, thereby expanding the use of low phosphorus, low sulfur and low sulfated ash engine lubricants. And natural gas engine lubricants.

  First generation low emission internal combustion engine lubricants were formulated to meet the above guidelines using low levels of detergent and zinc dialkyldithiophosphate. However, there is an expectation that at some point in the future, the maximum sulfur and phosphorus content will be much lower than we would expect from the industry and will proceed between 2010 and now. Low phosphorus lubricants were expected to provide some wear protection but were also expected to harm the oxidation catalyst. In an effort to explore the possibility of reducing catalyst poisoning while maintaining wear control, we have developed a trial lubricant containing a detergent containing a lithium salt of sulfurized phenate. Measurements of catalyst poisoning using these experimental lubricating oils with lithium-containing phenates in internal combustion engines showed that the results were predicted compared to lubricating oils with detergents containing calcium salts of sulfurized phenates. It showed a reduction in catalyst poisoning that could not be done. That is, since the phosphorus content of both lubricants was the same, if lithium-containing phenate was used in the lubricant composition instead of the calcium-containing detergent, it was shown that catalyst poisoning could be reduced while maintaining wear suppression. This result was surprising.

  Methods for reducing catalyst poisoning by reducing the phosphorus content of the lubricating oil are described in numerous patents and patent applications, all of which include (a) a major amount of oil of lubricating viscosity and (b) one type. Or two or more kinds of lithium-containing detergents, (c) one or more kinds of detergents other than lithium-containing detergents, (d) one or more kinds of antioxidants, and (e) one or more kinds of detergents. A lubricating oil composition comprising a dispersant and (f) one or more anti-wear additives, wherein the catalyst is poisoned while maintaining excellent wear control despite containing phosphorus. Lubricants that provide significant reduction are not disclosed.

  Patent Document 1 discloses a low ash low phosphorus motor oil with improved oxidative stability as a result of adding a synergistic amount of a dialkyldiphenylamine antioxidant and a sulfurized polyolefin. The synergistic action between the two additives compensates for the decrease in phosphorus content in the form of zinc dithiophosphate to the extent that the oil retains its SE quality rating.

  Patent Document 2 discloses an overbased additive containing lithium sulfonate suitable for use in lubricants and fuels, and a method for producing them. The TBN of the sulfonate is at least 250 milligrams KOH per gram.

  In Patent Document 3, (a) an alkylphenol is neutralized with an alkali metal hydroxide, (b) the product is carboxylated with carbon dioxide, and the initial alkali metal alkylphenate is converted into an alkali metal alkyl salicylate. And (c) alkyl salicylates for lubricating oils obtained by sulfidation-peralkalization of the product in the presence of an alkaline earth base and carbonation of the product with carbon dioxide. Contained detergent dispersants are disclosed.

  Patent Document 4 discloses a low phosphorus motor oil for passenger cars containing an oil of lubricating viscosity as a main component and a trimetallic detergent mixture as a minor component, wherein the trimetallic detergent mixture is at least one overbased calcium metal detergent. And a trimetallic detergent mixture in the lubricating oil composition, wherein the total TBN imparted to the oil is from about 2 to about TBN, comprising at least one overbased magnesium metal detergent and at least one overbased sodium metal detergent. A motor oil present in an amount such as 12 is disclosed.

  Patent Document 5 discloses a sodium-free non-thixotropic lubricating oil additive having 10% to 50% liquid organic diluent and 30% to 90% substituted hydrocarbon metal salt. At least 30 mol% of the metal of the metal salt is lithium, and the salt is essentially free of sodium. The non-thixotropic lubricating oil additive has a BN of less than 150 due to lithium. This additive is useful for reducing black sludge deposits and piston deposits.

  Patent Document 6 includes a base oil of lubricating viscosity, (a) at least one oil-soluble lithium-free overbased alkali or alkaline earth metal-containing overbased detergent, and (b) a TBN generally from 240 to 400. A lubricating oil additive concentrate comprising at least one oil-soluble overbased lithium salt detergent in the range is disclosed.

  Patent Document 7 discloses a lubricating oil composition containing at least one overbased alkali metal detergent as a lubricating oil additive effective for lubricating mechanical parts of land and marine engines. The overbased alkali metal detergent may be sulfurized and may contain at least 80% by weight alkyl hydroxybenzoate and the preferred alkali metal is potassium. This lubricating oil composition provides improved thermal stability and black sludge deposit control.

  Patent Document 8 discloses a lubricating oil effective for lubricating mechanical parts of land and marine engines such as hydraulic systems and transmissions, two-stroke and four-stroke vehicle engines, trunk pistons and two-stroke crosshead marine engines. An overbased detergent is disclosed as an additive. This overbased detergent provides improved cleanliness and thermal stability performance compared to highly overbased sulfonates. Furthermore, the miscibility with commercial phenates is better than conventional sulfonates.

Patent Document 9 discloses a composition containing at least one basic alkali metal salt of at least one hydrocarbon-substituted acidic organic compound, wherein the hydrocarbon group is derived from a polyalkylene having an _Mn of at least 600. However, when the organic compound is a sulfonic acid, the _Mn of the polyalkylene is at least 900, and the acidic organic compound has a hydrocarbon group derived from a carboxylic acid and a polyalkylene having an _Mn of less than 900. In the case of a mixture of acidic organic compounds containing sulfonic acid, the carboxylic acid accounts for at least 10% of the equivalent of the mixture.

In US Pat. No. 6,057,059, the hydrocarbon backbone is derived from an ethylene alpha olefin (EAO) copolymer having a terminal vinylidene unsaturation of> 30% and an M _n of 500 to 7000, or an alpha olefin alone or a copolymer. Also disclosed is a lubricating oil containing certain ashless dispersants containing an oil soluble high molecular weight hydrocarbon backbone with functional groups in combination with an overbased alkali metal additive. In particular, it relates to a crankcase lubricant that exhibits very good sludge and varnish control properties, provides excellent engine cleanliness and further oxidation resistance, and / or reduces the tendency to thicken due to interactions within the package. .

U.S. Pat. No. 4,304,420 U.S. Pat. No. 4,797,217 US Pat. No. 5,033,687 US Pat. No. 5,804,537 US Pat. No. 6,235,688 European Patent Application No. 96301587.0 (Publication No. EP071159A2) Specification US Patent Application No. 10 / 744,871 (Publication No. US 2005/0137100 A1) Specification US Patent Application No. 10/745125 (Publication No. US2005 / 0137098A1) Specification International Application No. PCT / US92 / 01476 (Publication No. WO92 / 18587) Pamphlet International Application No. PCT / EP95 / 02271 (Publication No. WO95 / 34619) Pamphlet

  The main object of the present invention is to provide a lubricating oil composition capable of reducing catalyst poisoning in an exhaust gas aftertreatment device of an internal combustion engine while maintaining wear suppression.

The present invention provides a lubricating oil composition comprising the following components.
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) one or more antioxidants,
(E) one or more dispersants, and (f) one or more antiwear additives,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent.

  In the lubricating oil composition of the present invention, the lithium concentration is preferably less than 0.08% by mass based on the total mass of the lubricating oil composition. More preferably, the concentration of lithium is less than 0.07% by weight based on the total weight of the lubricating oil composition, and most preferably the concentration of lithium is less than 0.05% by weight based on the total weight of the lubricating oil composition. It is.

  The lubricating oil composition of the present invention preferably has a low sulfur content and sulfated ash content.

  The phosphorus content of the lubricating oil composition of the present invention is preferably in the range of 0.03% to about 0.12% by weight based on the total weight of the lubricating oil composition. More preferably, the phosphorus content of the lubricating oil composition of the present invention is in the range of 0.05% to about 0.1% by weight based on the total weight of the lubricating oil composition. Most preferably, the phosphorus content of the lubricating oil composition of the present invention is in the range of 0.07 wt% to about 0.09 wt% based on the total weight of the lubricating oil composition.

  Examples of preferred low and medium overbased metal detergents that can be used in the lubricating oil composition of the present invention include low and medium overbased phenates, sulfurized phenates, aromatic sulfonates, salicylates, sulfurized salicylates, or alkylphenols. There is a Mannich condensation product of aldehyde and amine. More preferred are low and medium overbased phenates and sulfurized phenates. These detergents may be alkali metal detergents or alkaline earth metal detergents as long as the alkaline earth metal is not calcium. Alkali metal detergents are preferred, and medium overbased lithium detergents are more preferred. These detergents have a TBN greater than 1 and less than 200. Lithium-containing detergents can be prepared using the methods described in US Pat. No. 6,235,688 or by any method known to those skilled in the art.

  The concentration of lithium in the lithium-containing detergent used in the lubricating oil of the present invention is preferably in the range of about 0.5% to about 2.5% by weight based on the total weight of the lithium-containing detergent. More preferably, the concentration of lithium in the lithium-containing detergent is in the range of about 1.0% to about 2.0% by weight based on the total weight of the lithium-containing detergent. Most preferably, the concentration of lithium in the lithium-containing detergent is in the range of about 1.3% to about 1.75% by weight based on the total weight of the lithium-containing detergent.

  Examples of preferred antioxidants used in the lubricating oils of the present invention include diphenylamine type compounds, including but not limited to alkylated diphenylamine, phenyl-alpha-naphthylamine, and alkylated-alpha-naphthylamine. Is mentioned. Antioxidants that can be used include esters of thiodicarboxylic acid, dithiocarbamates such as 15-methylenebis (dibutyldithiocarbamate), salts of dithiophosphoric acid, alkyl or aryl phosphate esters. Molybdenum compounds such as amine-molybdenum complex compounds and molybdenum dithiocarbamates can also be used as antioxidants, and hindered phenols such as 4,4′-methylene-bis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 4,4′-bis (2-methyl-6-tert-butylphenol), 2,2′-methylene-bis (4-methyl-6) -T-butylphenol), 4,4'-butylidene-bis (3-methyl-6-t-butylphenol), 4,4'-isopropylidene-bis (2,6-di-t-butylphenol), 2,2 '-Methylene-bis (4-methyl-6-nonylphenol), 2,2'-isobutylidene-bis (4,6-dimethylphenol), 2,2'-5- Tylene-bis (4-methyl-6-cyclohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl- 6-t-butylphenol, 2,6-di-t-1-dimethylamino-p-cresol, 2,6-di-t-4- (N, N′-dimethylaminomethylphenol), 4,4′- Thiobis (2-methyl-6-tert-butylphenol), 2,2'-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4-hydroxy-5-t-10-butylbenzyl) -Sulphides and bis (3,5-di-tert-butyl-4-hydroxybenzyl) can also be used. More preferred are diphenylamine type compounds, most preferred are alkylated diphenylamines.

  A preferred dispersant that can be used in the lubricating oil composition of the present invention is an ashless dispersant. Examples of ashless dispersants are alkenyl succinimides and succinamides. These dispersants can be further modified, for example, by reaction with boron or ethylene carbonate. Ester ashless dispersants derived from long chain hydrocarbon-substituted carboxylic acids and hydroxy compounds can also be used. More preferred ashless dispersants are those derived from polyisobutenyl succinic anhydride, and most preferred are polyisobutenyl succinic anhydride derived dispersants treated with ethylene carbonate.

  Examples of antiwear additives include, but are not limited to, phosphate esters and thiophosphate esters and their salts, carbamates, esters, and molybdenum complexes. A preferred anti-wear additive contained in the lubricating oil composition of the present invention is a dialkyldithiophosphate metal salt. However, since the metal and phosphorus contribute to the lubricating oil, it can be said that it is advantageous to suppress the amount of this additive. Examples of dialkyldithiophosphate metal salts include zinc and molybdenum salts of dialkyldithiophosphates. The most preferred anti-wear additive used in the lubricating oil composition of the present invention is zinc dialkyldithiophosphate.

In another aspect of the present invention, a lubricating oil composition comprising the following components is provided.
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant,
(E) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent.

  The above lubricating oil composition comprises one or more detergents different from those listed in (b) unless the alkaline earth metal is calcium, and an antioxidant different from those listed in (c) Dispersants different from those listed in (d), antiwear additives, viscosity index improvers, ashless sulfur extreme pressure agents, alkaline earth metals and alkali metal boron different from those listed in (e) Oxidation extreme pressure agent, molybdenum-containing extreme pressure agent, pour point depressant, rust inhibitor, corrosion inhibitor, ash-containing friction modifier, ashless friction modifier, molybdenum-containing friction modifier, metal deactivator, seal One or more additives selected from swelling agents, demulsifiers and antifoaming agents can also be used.

  The lubricating oil composition of the above aspect preferably has a low sulfur and sulfated ash content.

In another aspect of the present invention, a lubricating oil concentrate comprising the following components is provided.
(A) an oil having a lubricating viscosity of about 10% to about 90% by weight;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) one or more antioxidants,
(E) one or more ash-containing dispersants, and (f) one or more antiwear additives,
However, the lubricating oil concentrate does not contain more than 0.1% by weight lithium and more than 0.12% by weight phosphorus, and the lubricating oil concentrate does not contain a calcium-containing detergent.

  In addition, the above-mentioned lubricating oil concentrate may contain one or more kinds of detergents different from those listed in (b) and oxidations different from those listed in (c), unless the alkaline earth metal is calcium. Inhibitors, dispersants different from those listed in (d), anti-wear additives, viscosity index improvers, ashless sulfur extreme pressure agents, alkaline earth metals and alkalis different from those listed in (e) Metal borated extreme pressure agent, molybdenum-containing extreme pressure agent, pour point depressant, rust inhibitor, corrosion inhibitor, ash-containing friction modifier, ashless friction modifier, molybdenum-containing friction modifier, metal deactivator One or more additives selected from seal swelling agents, demulsifiers and antifoaming agents can also be used.

In another aspect of the present invention, a lubricating oil concentrate comprising the following components is provided.
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant,
(E) a dispersant treated with ethylene carbonate;
(F) Phosphorus-containing antiwear additive, and (g) one or more cleaners different from those listed in (b), as long as the alkaline earth metal is not calcium, listed in (c) Antioxidants different from those described above, dispersants different from those listed in (d), anti-wear additives, viscosity index improvers, ashless sulfur extreme pressure agents, alkalis different from those listed in (e) Earth metal and alkali metal borated extreme pressure agent, molybdenum-containing extreme pressure agent, pour point depressant, rust inhibitor, corrosion inhibitor, ash-containing friction modifier, ashless friction modifier, molybdenum-containing friction modifier, One or more additives selected from metal deactivators, seal swelling agents, demulsifiers and antifoaming agents,
However, the lubricating oil concentrate does not contain more than 0.1% by weight lithium and more than 0.12% by weight phosphorus, and the lubricating oil concentrate does not contain a calcium-containing detergent.

In yet another aspect of the present invention, there is provided a method for reducing catalyst poisoning in an exhaust gas aftertreatment device for an internal combustion engine, the method comprising operating the internal combustion engine using a lubricating oil composition comprising the following components: provide.
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant,
(E) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent.

  In the method for reducing catalyst poisoning of the internal combustion engine, the internal combustion engine is a diesel engine, a gasoline engine, or a natural gas engine.

  Moreover, in the said aspect, as long as an alkaline-earth metal is not calcium, the lubricating oil composition is a 1 type, or 2 or more types of cleaning agent different from what was mentioned in (b), oxidation different from what was mentioned in (c). Inhibitors, dispersants different from those listed in (d), anti-wear additives, viscosity index improvers, ashless sulfur extreme pressure agents, alkaline earth metals and alkalis different from those listed in (e) Metal borated extreme pressure agent, molybdenum-containing extreme pressure agent, pour point depressant, rust inhibitor, corrosion inhibitor, ash-containing friction modifier, ashless friction modifier, molybdenum-containing friction modifier, metal deactivator One or more additives selected from seal swelling agents, demulsifiers and antifoaming agents can also be used.

  It has been discovered that the lubricating oil composition of the present invention results in reduced catalyst poisoning while maintaining wear inhibition. In conventional lubricating oil compositions, wear inhibition is achieved by the addition of a metal salt of a dialkyldithiophosphate, such as a zinc dialkyldithiophosphate. However, phosphorus in the dialkyldithiophosphate causes deactivation of the oxidation catalyst used in the exhaust gas aftertreatment device. The lubricating oil composition of the present invention provides reduced catalyst poisoning despite containing the same amount of phosphorus as the comparative example. It is conventional knowledge that phosphorus-containing additives in lubricating oils are detrimental to the catalyst, and what was not known is that catalyst poisoning can be reduced even when lithium-containing phenates are present in the presence of phosphorus.

  As used herein, the following terms have the following meanings unless otherwise indicated.

  “Alkali metal” as used herein means a Group IA metal of the periodic table.

  “Alkaline earth metal” as used herein means a Group II metal of the periodic table, for example magnesium, but the alkaline earth metal is not calcium.

  “Overbasic” as used herein is an alkali metal and alkaline earth metal alkyl sulfonate wherein the ratio of the number of equivalents of alkali metal or alkaline earth metal to the number of equivalents of organic moiety is greater than one Means things. Low overbasic means an alkali metal or alkaline earth metal alkyl sulfonate having a total base number (TBN) greater than 1 and less than 20, and medium overbasic means an alkali metal or alkali with a TBN greater than 20 and less than 200. Means an earth metal alkyl sulfonate. High overbasing means an alkali metal or alkaline earth metal alkyl sulfonate with a TBN greater than 200.

  “Sulfated ash” as used herein means non-combustible residues resulting from detergents and metallic additives in the lubricating oil. The ASTM D874 test can be used to determine sulfated ash.

  “Total base number” or “TBN” as used herein means the amount of base equivalent to milligrams of KOH in a gram of sample. Therefore, the higher the TBN value, the stronger the alkalinity of the product, which reflects the higher alkalinity. The TBN was determined using the ASTM D2896 test.

  Unless otherwise specified, all percentages are weight percent.

[Lubricating oil composition]
The lubricating oil composition of the present invention can be produced by simply blending or mixing the compounds described in detail below. In order to facilitate blending of lubricating oil compositions containing the desired concentration of additives, these compounds can also be pre-blended as a concentrate or package in appropriate proportions with various other additives. it can.

(Oil of lubricating viscosity)
As used herein, an oil or base oil of lubricating viscosity means a lubricating oil, which may be a mineral oil or a synthetic oil of lubricating viscosity, but can preferably be used in a crankcase of an internal combustion engine. Is. The viscosity of the crankcase lubricant is typically about 1300 centistokes at -17.8 ° C to 22.7 centistokes at 98.9 ° C.

Lubricating oils can be derived from synthetic or natural sources. Mineral oils used as base oils in the present invention can include paraffinic, naphthenic, and other oils commonly used in lubricating oil compositions. Synthetic oils include hydrocarbon synthetic oils and synthetic esters. Synthetic hydrocarbon oils that can be used include liquid polymers of alpha-olefins having the proper viscosity. Particularly useful are hydrogenated liquid oligomers of C ₆ -C ₁₂ alpha-olefins such as 1-decene trimer. Similarly, alkylbenzenes of the proper viscosity, such as didodecylbenzene, may be used. Synthetic esters that can be used include esters of monocarboxylic acids and polycarboxylic acids with monohydroxyalkanols and polyols. Representative examples include didodecyl adipate, pentaerythritol tetracaproate, di-2-ethylhexyl adipate, and dilauryl sebacate. Complex esters synthesized from mixtures of mono and dicarboxylic acids and mono and dihydroxy alkanols can also be used.

  A blend of hydrocarbon oil and synthetic oil may be used. For example, blends of 10% to 25% by weight of hydrogenated 1-decene trimer with 75% to 90% by weight of 683 centistokes mineral oil at 37.8 ° C. Become. A Fischer-Tropsch derived base oil may also be used in the lubricating oil composition of the present invention.

  Further, it is conceivable that the oil of lubricating viscosity used for producing the lubricating oil composition of the present invention is a low sulfur base oil. The use of a low sulfur base oil helps to obtain a lubricating oil composition having a very low sulfur content. The sulfur content of the base oil is well known to those skilled in the art, so a low sulfur base oil can be selected as appropriate for the present invention.

(Low and medium overbased metal detergents)
Examples of preferred low and medium overbased metal detergents that can be used in the lubricating oil compositions of the present invention include low and medium overbased phenates, sulfurized phenates, aromatic sulfonates, salicylates, sulfurized salicylates or alkylphenols. There are Mannich condensation products of aldehydes and amines. More preferred are low and medium overbased phenates and sulfurized phenates. These detergents may be alkali metal detergents or alkaline earth metal detergents as long as the alkaline earth metal is not calcium. Alkali metal detergents are preferred, and medium overbased lithium detergents are more preferred. These detergents have a TBN greater than 1 and less than 200.

  The concentration of lithium in the lithium-containing detergent used in the lubricating oil of the present invention is preferably in the range of about 0.5% to about 2.5% by weight based on the total weight of the lithium-containing detergent. More preferably, the concentration of lithium in the lithium-containing detergent is in the range of about 1.0% to about 2.0% by weight based on the total weight of the lithium-containing detergent. Most preferably, the concentration of lithium in the lithium-containing detergent is in the range of about 1.3% to about 1.75% by weight based on the total weight of the lithium-containing detergent.

  The majority of these detergents are known in the art and are also commercially available. Lithium-containing detergents can be prepared using the methods described in US Pat. No. 6,235,688 or by any method known to those skilled in the art.

(Antioxidant)
Examples of preferred antioxidants used in the lubricating oils of the present invention include diphenylamine type compounds, including but not limited to alkylated diphenylamine, phenyl-alpha-naphthylamine, and alkylated-alpha-naphthylamine. Is mentioned. Antioxidants that can be used also include esters of thiodicarboxylic acid, dithiocarbamates such as 15-methylenebis (dibutyldithiocarbamate), salts of dithiophosphoric acid, alkyl or aryl phosphate esters. Molybdenum compounds such as amine-molybdenum complex compounds and molybdenum dithiocarbamates can also be used as antioxidants, and hindered phenols such as 4,4′-methylene-bis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 4,4′-bis (2-methyl-6-tert-butylphenol), 2,2′-methylene-bis (4-methyl-6) -T-butylphenol), 4,4'-butylidene-bis (3-methyl-6-t-butylphenol), 4,4'-isopropylidene-bis (2,6-di-t-butylphenol), 2,2 '-Methylene-bis (4-methyl-6-nonylphenol), 2,2'-isobutylidene-bis (4,6-dimethylphenol), 2,2'-5-methylene-bi (4-methyl-6-cyclohexylphenol), 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,4-dimethyl-6-t -Butylphenol, 2,6-di-t-1-dimethylamino-p-cresol, 2,6-di-t-4- (N, N'-dimethylaminomethylphenol), 4,4'-thiobis (2 -Methyl-6-t-butylphenol), 2,2'-thiobis (4-methyl-6-t-butylphenol), bis (3-methyl-4-hydroxy-5-t-10-butylbenzyl) -sulfide, And bis (3,5-di-tert-butyl-4-hydroxybenzyl) can also be used. More preferred are diphenylamine type compounds, most preferred are alkylated diphenylamines.

(Dispersant)
A preferred dispersant that can be used in the lubricating oil composition of the present invention is an ashless dispersant. Examples of ashless dispersants are alkenyl succinimides and succinamides. These dispersants can be further modified, for example, by reaction with boron or ethylene carbonate. Ester ashless dispersants derived from long chain hydrocarbon-substituted carboxylic acids and hydroxy compounds can also be used. More preferred ashless dispersants are those derived from polyisobutenyl succinic anhydride, and most preferred are polyisobutenyl succinic anhydride derived dispersants treated with ethylene carbonate. A number of dispersants are commercially available.

(Abrasion resistance additive)
Examples of antiwear additives include, but are not limited to, phosphate esters and thiophosphate esters and their salts, carbamates, esters, and molybdenum complexes. A preferred anti-wear additive contained in the lubricating oil composition of the present invention is a metal dialkyldithiophosphate. However, since the metal and phosphorus contribute to the lubricating oil, it can be said that it is advantageous to suppress the amount of this additive. Examples of metal dialkyldithiophosphates include zinc and molybdenum salts of dialkyldithiophosphates. The most preferred anti-wear additive used in the lubricating oil composition of the present invention is zinc dialkyldithiophosphate.

[Other additives]
In addition to the additives described above, the lubricating oil composition of the present invention may also contain other additives that are used to impart desired properties to the lubricating oil composition of the present invention. Therefore, the lubricating oil may contain one or more additives such as a viscosity index improver, a pour point depressant, a demulsifier, an extreme pressure agent, and an antifoaming agent. In the following, these additional additives are described in detail.

(Viscosity index improver)
Viscosity index improvers are added to lubricating oils to adjust viscosity changes due to temperature changes. Some examples of commercially available viscosity index improvers include olefin copolymers such as ethylene-propylene copolymers, styrene-isoprene copolymers, hydrated styrene-isoprene copolymers, polybutenes, polyisobutylenes, There are polymethacrylates, copolymers of vinyl pyrrolidone and methacrylate, and dispersion type viscosity index improvers.

(Extreme pressure agent)
Examples of extreme pressure agents that can be used in the lubricating oil composition of the present invention include alkaline earth metal borated extreme pressure agents and alkali metal borated extreme pressure agents. Extreme pressure agents containing molybdenum may also be used in the lubricating oil composition of the present invention as long as the molybdenum compound does not contain trinuclear molybdenum. Sulfurized olefin, zinc dialkyl-1-dithiophosphate (primary alkyl, secondary alkyl and aryl type), diphenyl sulfide, methyltrichlorostearate, chlorinated naphthalene, fluoroalkylpolysiloxane, lead naphthenate, neutralized or partial Neutralized phosphate esters, dithiophosphate esters, and sulfur-free phosphate esters. Preferred extreme pressure agents are those that do not contribute to the phosphorus content of the lubricating oil.

(Pour point depressant)
Polymethylmethacrylate is an example of a pour point depressant that can be used to add to the lubricating oil of the present invention.

(Anti-rust additive)
Anti-corrosive additives include nonionic polyoxyethylene surfactants such as polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl stearyl Mention may be made of ethers, polyoxyethylene oleyl ethers, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate, and polyethylene glycol monooleate. Other compounds that can be used as rust inhibitors include stearic acid and other fatty acids, dicarboxylic acids, metal soaps, fatty acid amine salts, metal salts of heavy sulfonic acids, and partial carboxylic acid esters of polyhydric alcohols. , And phosphate esters. However, preferred rust inhibitors are those that do not contribute to the phosphorus or sulfur content of the lubricating oil.

(Corrosion inhibitor)
Corrosion inhibitors are included in lubricating oils to protect sensitive metal surfaces. Such corrosion inhibitors are generally used in very small amounts in the range of about 0.02% to about 1.0% by weight. Examples of corrosion inhibitors that can be used include sulfurized olefin corrosion inhibitors and co-sulfurized alkenyl ester / alpha olefin corrosion inhibitors. The corrosion inhibitor should not be a metal dithiophosphate, in particular zinc dialkyldithiophosphate, because the addition of this corrosion inhibitor will contribute to the zinc, phosphorus and sulfur content of the lubricating oil.

(Friction modifier)
Examples of the friction modifier used in the lubricating oil composition of the present invention include both ash-containing friction modifiers and ashless friction modifiers. Friction modifiers include, but are not limited to, fatty alcohols, fatty acids such as stearic acid, isostearic acid, oleic acid and other fatty acids, or salts and esters thereof, borated esters, amines, phosphoric acids. Mention may be made of esters, and di- and tri-hydrocarbon phosphate esters, hydrocarbon phosphite esters and phosphonate esters. The friction modifier may contain molybdenum as long as the molybdenum compound does not contain trinuclear molybdenum. Preferably, the friction modifier used in the lubricating oil composition of the present invention is an ashless friction modifier.

(Metal deactivator)
Metal deactivators that can be used in the lubricating oil composition of the present invention include, but are not limited to, disalicylidenepropylenediamine, triazole derivatives, mercaptobenzothiazole, thiadiazole derivatives, and mercaptobenz. Mention may be made of imidazole.

(Seal swelling agent)
The lubricating oil composition of the present invention may use seal swell agents, including but not limited to diesters such as di-2-ethylhexyl sebacate, dioctyl adipate and di-2-ethylhexyl phthalate, tridecyl Mention may be made of mineral oils containing aliphatic alcohols such as alcohols, and tris phosphites in combination with hydrocarbonyl-substituted phenols.

(Demulsifier)
An adduct of alkylphenol and ethylene oxide, polyoxyethylene alkyl ether, and polyoxyethylene sorbitan ester can be used in the lubricating oil composition of the present invention.

(Defoamer)
Antifoaming agents that can be used in the present invention are alkyl methacrylate polymers, dimethyl silicone polymers, and polysiloxane type antifoaming agents.

  In order to obtain the best overall results in view of imparting the desired properties to conventional lubricating oil compositions for lubricating diesel engines, gasoline engines and natural gas engines, lubricating oils are a class of additives described above. Each of the miscible additive combinations can be included in an effective amount.

  The various additive materials or classes of materials described herein are well-known materials that can be easily purchased commercially or produced by known methods or obvious modifications thereof. .

  Table 1 below shows the processing ratio of additives that can be used in the lubricating oil of the present invention. All component amounts are stated as mass% of active additive.

Table 1 ─────────────────────────────────────
Component Range Preferred Range Most preferred
(Mass%) (mass%) Range (mass%)
─────────────────────────────────────
Detergent 0-10 0.5-8 1-6
Antioxidant 0-3.0 0.2-2.0 0.2-1.5
Dispersant 0-12 1-10 2-8
Abrasion resistance additive 0-5 0.1-3 0.2-2
Viscosity index improver 0-3 0.2-2 0.3-1
Extreme pressure agent 0-2.0 0-1.0 0.1-0.5
Pour point depressant 0-1.0 0.05-0.5 0.05-0.3
Rust prevention additive 0-1.0 0-0.75 0.05-0.5
Corrosion inhibitor 0-3.0 0.2-2.0 0.2-1.5
Friction modifier 0-1.0 0.05-0.75 0.1-0.5
Antifoam 0-3.0 0.2-2.0 0.2-1.5
─────────────────────────────────────

  The lubricating oil composition of the present invention was evaluated for its ability to reduce catalyst poisoning with formulations prepared as described in Example 1 and Table 1 below.

[Example 1]
Comparative formulation A and test formulation B contained an amine-containing antioxidant, an ethylene carbonate-treated dispersant, a phosphorus-containing antiwear additive, a viscosity index improver and an antifoaming agent. Comparative formulation A also contained medium overbased calcium sulfurized phenate, and test formulation B contained medium overbased lithium sulfurized phenate. Base oil was used to make each of Comparative Formulation A and Test Formulation B 100%.

  Reduced catalyst poisoning when using test formulation B containing medium overbased lithium sulfurized phenate in addition to the other components, comparative formulation containing medium overbased calcium sulfurized phenate in addition to the other components Comparison with product A.

  Details of Comparative Formulation A and Test Formulation B are listed in Table 2 below. The amounts of the components of the lubricating oil formulation are listed in Table 2 in terms of mass% active additive.

Table 2 ─────────────────────────────────
Ingredient composition (mass%)
Comparative formulation A Test formulation B
────────────────────────────────
Base oil Residual Residue Lithium-containing phenate 0 1.6
Calcium-containing phenate 1.6 0
Amine-containing antioxidant 0.5 0.5
Ethylene carbonate-treated dispersant 2.4 2.4
Phosphorus-containing antiwear additive 0.83 0.83
Antifoaming agent 5ppm 5ppm
────────────────────────────────

  Table 3 below shows the amount of phosphorus in Comparative Formulation A and Test Formulation B.

Table 3
──────────────────────
Ingredient (mass%)
Comparative formulation A Test formulation B
──────────────────────
Phosphorus 0.093 0.093
──────────────────────

Example 2 Catalyst poisoning As described below, the reduction in catalyst poisoning in the exhaust gas aftertreatment device was determined with test formulation B and compared with comparative formulation A.

  Catalyst poisoning was measured using a Honda E5 generator set with a 0.3 liter, 2 cylinder, OHC engine. In order to promote catalyst aging, the catalyst core was made smaller than usual and the engine valve guide was removed. The catalyst core was placed far enough from the downflow to prevent sintering. After catalyst aging, the conversion efficiency of the core and the deposited additive metal were measured using a synthesis gas reactor.

  The gas reactor was operated in three different states: lean, rich and confused. The confused state most closely simulates the engine environment by alternating the gas mixture between lean and rich states. The experiment consisted of measuring the conversion efficiency of hydrocarbons, carbon monoxide and nitrogen oxides as a function of time and temperature given by a predetermined temperature increase. The temperature increase was planned to simulate the warm-up operation of the catalytic converter during the engine start-up process. The temperature was increased non-linearly from a baseline temperature of 150 ° C. to a maximum of 425 ° C. After reaching a certain temperature, the conversion rapidly increased when the catalyst “ignited”. The temperature at which 50% conversion (T50) is observed is taken as the measured value for ignition and catalyst poisoning. Thus, the lower the T50, the more positive the conversion and the negative the catalyst poisoning.

  The data reported is the T50 at the end of the test. Table 4 below summarizes the results of the catalyst poisoning test.

Table 4
──────────────────────────
Catalyst poisoning test Comparative formulation A Test formulation B
──────────────────────────
T50 314 ° C 294 ° C
──────────────────────────

  The results obtained in the catalyst poisoning tests summarized in Table 4 above are for Comparative Formula A containing medium overbased calcium sulfide phenate, measured at T50 as the temperature when the catalyst “ignited”. The determined catalyst poisoning was 314 ° C., while the T50 measured for test formulation B containing medium overbased lithium sulfide phenate was 294 ° C. Data show that addition of medium overbased lithium sulfurized phenate to test formulation B reduces catalyst poisoning by 7% compared to catalyst poisoning observed with comparative formulation A containing medium overbased calcium sulfurized phenate At the same time, the same wear suppression was maintained.

  The results of the catalyst poisoning tests summarized in Table 4 above show that the test formulation B using the lithium-containing phenate reduced the catalyst poisoning compared to the comparative formulation A containing the calcium-containing phenate. It is clear. Since the phosphorus content of test formulation B and comparative formulation A was the same, such a result was unpredictable. It has been known that phosphorus-containing additives in lubricating oils are harmful to the catalyst, but it was not known that lithium-containing phenates in lubricating oils can reduce catalyst poisoning even in the presence of phosphorus. It is. From the conventional knowledge, this was a phenomenal result.

Claims (26)

A lubricating oil composition comprising the following ingredients:
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) one or more antioxidants,
(E) one or more dispersants, and (f) one or more antiwear additives,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent.   The lubricating oil composition according to claim 1, wherein the concentration of lithium in the lubricating oil composition is less than 0.08 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition according to claim 2, wherein the concentration of lithium in the lubricating oil composition is less than 0.07 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition according to claim 3, wherein the concentration of lithium in the lubricating oil composition is less than 0.05 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition of claim 1, wherein the phosphorus content is in the range of 0.03% to about 0.12% by weight based on the total weight of the lubricating oil composition.   The lubricating oil composition of claim 5, wherein the phosphorus content is in the range of 0.05 wt% to about 0.1 wt% based on the total weight of the lubricating oil composition.   The lubricating oil composition of claim 6, wherein the phosphorus content is in the range of 0.07 wt% to about 0.09 wt% based on the total weight of the lubricating oil composition. A lubricating oil composition comprising the following ingredients:
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant,
(E) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent.   The lubricating oil composition according to claim 8, wherein the concentration of lithium in the lubricating oil composition is less than 0.08 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition according to claim 9, wherein the concentration of lithium in the lubricating oil composition is less than 0.07 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition according to claim 10, wherein the concentration of lithium in the lubricating oil composition is less than 0.05 mass% based on the total mass of the lubricating oil composition.   The lubricating oil composition of claim 8, wherein the phosphorus content is in the range of 0.03% to about 0.12% by weight based on the total weight of the lubricating oil composition.   The lubricating oil composition of claim 12, wherein the phosphorus content is in the range of 0.05 wt% to about 0.1 wt% based on the total weight of the lubricating oil composition.   The lubricating oil composition of claim 13, wherein the phosphorus content is in the range of 0.07 wt% to about 0.09 wt% based on the total weight of the lubricating oil composition.   The lubricating oil composition according to claim 8, wherein the lithium-containing detergent is an overbased lithium phenate, an overbased lithium sulfurized phenate, an overbased lithium salicylate, or an overbased lithium carboxylate.   The lubricating oil composition according to claim 15, wherein the lithium-containing detergent is an overbased lithium phenate or an overbased lithium sulfurized phenate.   The lubricating oil composition of claim 16, wherein the lithium-containing detergent is an overbased lithium sulfurized phenate.   The lubricating oil composition according to claim 8, wherein the phosphorus-containing antiwear additive is a dialkyldithione phosphate metal salt.   The lubricating oil composition according to claim 18, wherein the metal of the metal dialkyldithione phosphate is zinc. Lubricating oil concentrate containing the following ingredients:
(A) an oil of lubricating viscosity of about 10% to about 90% by weight, based on the total weight of the lubricating oil concentrate;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant,
(E) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive,
However, the lubricating oil concentrate does not contain more than 0.1% by weight lithium and more than 0.12% by weight phosphorus, and the lubricating oil concentrate does not contain a calcium-containing detergent.   21. The lubricating oil concentrate of claim 20, wherein the lithium-containing detergent is an overbased lithium sulfurized phenate.   21. The lubricating oil concentrate of claim 20, wherein the phosphorus-containing antiwear additive is zinc dialkyldithione phosphate. A method for reducing catalyst poisoning in an exhaust gas aftertreatment device of an internal combustion engine, the method comprising operating the internal combustion engine using a lubricating oil composition comprising the following components:
(A) a major amount of oil of lubricating viscosity;
(B) a lithium-containing detergent,
(C) one or more detergents other than the lithium-containing detergent,
(D) an amine-containing antioxidant and a phenolic antioxidant,
(E) a dispersant treated with ethylene carbonate, and (f) a phosphorus-containing antiwear additive,
However, the lubricating oil composition does not contain lithium in an amount greater than 0.1% by weight and phosphorus in an amount greater than 0.12% by weight, and the lubricating oil composition does not contain a calcium-containing detergent. .   The method according to claim 23, wherein the internal combustion engines are diesel engines, gasoline engines and natural gas engines.   24. The method of claim 23, wherein the lithium-containing detergent is an overbased lithium sulfurized phenate.   24. The method of claim 23, wherein the phosphorus-containing antiwear additive is zinc dialkyldithione phosphate.