JP2004149802A - Low-phosphorus lubricating oil composition for extended drain interval - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil composition for reducing wear and controlling oxidation and intended for extended drain interval application. <P>SOLUTION: A lubricating oil composition comprising a major amount of a base oil of lubricating viscosity and a minor amount of each of the following: (a) from about 3.0 to about 7.0 wt.% of an ethylene carbonated-treated ashless dispersant; (b) from about 2.0 to about 5.0 wt.% of a borate-treated ashless dispersant; wherein the weight ratio of (a) to (b) is about 0.3 to about 0.5; (c) from about 1.0 to about 3.0 wt.% of a high overbased metal-containing detergent; (d) from about 0.1 to about 2.0 wt.% of a phosphorus-containing compound; wherein the weight percent of total phosphorus in the lubricating oil composition is no more than 0.08 wt.% based on the total weight of the lubricating oil composition. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a lubricating oil composition having improved wear, extreme pressure and oxidation performance in an internal combustion engine. The present invention particularly provides a lubricating oil composition for reducing wear and suppressing oxidation in an internal combustion engine lubricated with a low-phosphorus lubricating oil, intended to lengthen the oil change interval, and a method using the same. About.

  Recent passenger car oils that meet the American Petroleum Institute (API) "SL" standard or the International Lubricant Standards and Authorization Commission (ILSAC) GF-3 standard are listed in the Owner's Manual of the Original Equipment Manufacturer (OEM). The oil change interval is designed to be about 5,000 miles (8000 kilometers) or less, depending on the operating severity of the vehicle. These oils are based on the American Automobile Engineers Association (SAE) Land Vehicle Standard J183 (June 2001) to demonstrate, among other requirements, oxidative stability, wear, sludge and varnish deposit control, for example. And has passed a series of stringent industry standard engine and bench tests documented by the American Society for Testing and Materials (ASTM) D4485-01a (February 2002). However, significant increases in performance standards have evolved. Soon, the next generation of engine oil will meet the proposed ILSAC GF-4 standard.

  With the increasing emphasis on oil savings and the need for more maintenance-free vehicles, the trend is to extend the interval between engine oil changes. Modern API SL quality engine oils provide good engine cleanliness and wear protection at standard oil change intervals of 3000 to 10000 miles. However, as the recommended oil change interval increases, problems with excessive oil thickening, increased engine sludge and / or varnish deposits, and engine wear have become apparent in many SL products.

  Extending the oil change period has recently been considered throughout the automotive lubrication industry and has been part of the original debate on future engine oil specification requirements (ILSAC GF-4). The recommendation to extend the oil change interval beyond 15,000 miles is being discussed today. OEMs are interested in extending the oil change intervals of engine oils without degrading the deposit and wear performance of the lubricating oil composition. Of great importance to some OEMs is protecting the engine during harsh operating services, on all vehicles rented, or during lease periods when the driver is less likely to keep the vehicle in place. For example, one OEM wants an engine oil that is applied with sufficient factory production and service that can drive at least 30,000 miles before the next engine oil change. This is particularly desirable in leased vehicles that do not change the engine oil at appropriate recommended service intervals, but sometimes at longer intervals. Providing a lubricating oil composition that meets this requirement and the ILSAC GF-4 standard is the ultimate challenge.

  The problem of providing an automotive oil formulation that allows for longer oil change intervals is a significant problem. Essentially, the oil must be able to provide satisfactory lubrication for as long as was required in the past, ie for three to six months. At the same time, the oil must be kept free of harmful sludge deposits on the crankcase and other parts of the engine, and rust and rust on engine parts such as valve lifters under extreme contact pressure. It must provide protection from corrosion as well as wear protection. In addition, automotive oils that allow longer oil change intervals have properties that are compatible with spark ignition engines, such as oxidative stability, viscosity retention, cold start characteristics, constant combustion chamber control features, and consumers can use all higher grade oils. You have to keep the oil mileage and fuel economy you have come to expect. While additives are known that can enhance one or perhaps two of these properties, careful and extensive experimentation has been conducted because of the large number of ingredients that have specific interactions with other lubricating additives. This results in a truly useful automotive oil formulation with a more severe oil change interval.

  An important requirement of the proposed ILSAC GF-4 standard is to reduce the phosphorus level from the current allowable limit of 0.10% by weight specified in the ILSAC GF-3 standard to around 0.05% by weight. . Phosphorus and its derivatives harm the catalytic components of the catalytic converter. This is because effective catalytic converters must meet government regulations designed to reduce pollution and reduce toxic gases such as hydrocarbons, carbon monoxide and nitric oxide in the exhaust of internal combustion engines. Is a major concern. Such catalytic converters typically use a combination of platinum or a variant thereof and a catalytic metal, such as a metal oxide, and are installed in the exhaust stream to convert toxic gases to non-toxic gases. If the amount of phosphorus in the exhaust is excessive, the components of the catalytic converter may become ineffective and eventually lose their intended function.

  One class of additives to which the new specification has had a strong impact are the phosphorus-containing additives used in lubricating oil compositions for internal combustion engines. For example, zinc dialkyldithiophosphates are included in most commercially available internal combustion engine oils, especially those used in motor vehicles, because of their favorable properties as antiwear agents and performance as antioxidants. When used for wear control, it is generally used at a phosphorus level of about 0.1% by weight in the lubricating oil. Problems occur with reduced levels of phosphorus, including phosphorus-containing compounds, resulting in a significant reduction in wear and oxidation inhibition performance resulting from this reduction in phosphorus levels. Therefore, there is a need to find a way to reduce phosphorus while maintaining the wear and oxidation properties of high phosphorus engine oils.

To obtain higher fuel efficiency from the engine, lower viscosity lubricants are required. The only way to meet the SAE 0W20 engine oil combination requirements is to use a synthetic base oil. Until recently, the combination of C ₇ ester liquid polyalphaolefin such as tetra-methanol propane ester -C ₉ (PAO) base oil meets the requirements of SAE 0W20 while maintaining oxidative stability and acceptable oils consumption It was one way. The SAE 0W20 viscosity grade represents the lowest viscosity grade likely to be utilized by OEMs in applications with sufficient factory production and service. This grade of engine oil is typically formulated with a polyalphaolefin (PAO) base oil. This is because base oils derived from crude oil cannot meet the combination of volatility and low temperature requirements for this viscosity grade.

  SUMMARY OF THE INVENTION The present invention relates to lubricating oil compositions having properties that allow for longer oil change intervals as evidenced by improved wear, extreme pressure and oxidation performance.

  The present invention provides a lubricating oil composition having improved wear, extreme pressure and oxidation performance in an internal combustion engine. In particular, the present invention provides a lubricating oil composition for reducing wear and suppressing oxidation in an internal combustion engine lubricated with a low phosphorus lubricating oil intended for use at long oil change intervals, and using the same. About the method.

Thus, in one aspect of the composition, the present invention provides:
For a lubricating oil composition comprising a major amount of a base oil of lubricating viscosity and a minor amount of each of the following components:
a) from about 3.0 to about 7.0% by weight of an ethylene carbonated ashless dispersant;
b) about 2.0 to about 5.0% by weight of a borated ashless dispersant;
Wherein the weight ratio of a) to b) is from about 0.3 to about 0.5;
c) about 1.0 to about 3.0% by weight of a highly overbased metal-containing detergent;
d) from about 0.1 to about 2.0% by weight of a phosphorus-containing compound;
However, the weight% of the total phosphorus in the lubricating oil composition is 0.08% by weight or less based on the total weight of the lubricating oil composition.

  The lubricating oil composition of the present invention may further contain a low overbased metal-containing detergent, a nitrogen-containing ashless antioxidant, an alkylthiocarbamoyl compound, a molybdenum-succinimide complex, or a mixture thereof.

  In a preferred embodiment, the total amount of phosphorus in the composition is no more than 0.05% by weight, based on the total weight of the composition.

  The base oil having a lubricating viscosity is preferably selected from the group consisting of a Group III base oil, a Group IV base oil, a Group V base oil, and an arbitrary mixture thereof.

  The ashless dispersant is preferably selected from the group consisting of alkenyl succinimides, alkenyl succinic anhydrides, alkenyl succinates, benzylamines and mixtures thereof. More preferably, the ashless dispersant is an alkenyl succinimide.

  Preferably, the metal-containing detergent is a metal phenate or a metal sulfonate. Metal sulfonates are more preferred.

  Oil-soluble phosphorus-containing antiwear compounds include metal dithiophosphates, phosphorus esters (phosphate esters, phosphonate esters, phosphinate esters, phosphine oxides, phosphite esters, phosphonite esters, phosphinate esters and phosphine esters). Etc.), amine phosphates, amine phosphinates, sulfur-containing phosphorus esters including phosphorus monothionates and dithionates, phosphorus amides, phosphonamides and the like. More preferably, the phosphorus-containing compound is a metal dithiophosphate, and even more preferably, zinc dithiophosphate.

  Preferably, the nitrogen-containing ashless antioxidant is an alkylated diphenylamine.

  The alkylthiocarbamoyl compound is preferably an alkylenebis (dialkyldithiocarbamate).

  Preferably, the molybdenum / nitrogen-containing compound complex is molybdenum-succinimide. Complexes include both sulfided and unsulfurized forms, preferably the complex is sulfided.

  Particularly preferred molybdenum / nitrogen containing compound complexes are disclosed in U.S. patent application Ser. No. 10 / 159,446, filed May 31, 2002, entitled "Color-Reduced Molybdenum-Containing Compositions and Methods of Making Same" The contents of the application are all described in this specification as reference.

The present invention is a method for extending the life of a lubricating oil composition as evidenced by improved wear, extreme pressure and oxidation performance, comprising a base oil of a major amount of lubricating viscosity and a lubricating oil comprising a minor amount of each of the following components: A method comprising operating an internal combustion engine with the composition:
a) from about 3.0 to about 7.0% by weight of an ethylene carbonated ashless dispersant;
b) about 2.0 to about 5.0% by weight of a borated ashless dispersant;
Wherein the weight ratio of a) to b) is from about 0.3 to about 0.5;
c) about 1.0 to about 3.0% by weight of a highly overbased metal-containing detergent;
d) from about 0.1 to about 2.0% by weight of a phosphorus-containing compound;
However, the weight percentage of total phosphorus in the lubricating oil composition is 0.08% by weight or less based on the total weight of the lubricating oil composition.

  Among other factors, the present invention is based on the surprising discovery that lubricating oil compositions can extend oil change intervals as evidenced by improved wear, extreme pressure and oxidation performance. The lubricating oil composition of the present invention maintains excellent wear and oxidation performance, which is important in lubricating oils capable of extending the oil change interval, while having a low phosphorus content.

  The present invention provides a low phosphorus lubricating oil composition having a total phosphorus content of 0.08 wt% or less based on the total weight of the composition. The combination of additive components in the lubricating oil composition of the present invention improves wear, extreme pressure and oxidation performance. The details will be described below.

[Base oil of lubricating viscosity]
The lubricant composition of the present invention contains a major amount of a base oil of lubricating viscosity. As used herein, a base oil is defined as a lubricant component base stock or blend of base stocks manufactured by a single manufacturer to the same specifications (independent of source and manufacturer location). That is, it meets the specifications of the same manufacturer and is identified by a unique recipe, product identification number, or both. Feedstocks can be produced using a variety of different processes, including, but not limited to, distillation, solvent refining, hydrotreating, oligomerization, esterification, and rerefining. Rerefined stocks are substantially free of materials introduced by manufacturing, contamination, or previous use. The base oil of the present invention may be any natural or synthetic lubricating base oil fraction, especially one having a kinematic viscosity of about 4 centistokes (cSt) to about 20 cSt at 100 degrees Celsius (° C.). . Examples of the hydrocarbon synthetic oil include an oil synthesized from polymerization of ethylene, that is, an oil synthesized from polyalphaolefin or PAO, or an oil synthesized from a hydrocarbon synthesis method such as a Fischer-Tropsch method using carbon monoxide and hydrogen gas. be able to. Preferred base oils are those that contain some, if any, heavy fractions, such as lubricating oil fractions having a viscosity at about 100 ° C. of about 20 cSt or greater.

  The base oil can be derived from natural lubricating oils, synthetic lubricating oils, or mixtures thereof. Suitable base oils include feedstocks obtained by the isomerization of synthetic and crude waxes, as well as hydrogenation produced by hydrocracking (rather than solvent extraction) the aromatic and polar components of the crude. Cracked feedstocks can be mentioned. Suitable base oils include those in all API categories I, II, III, IV and V as defined in API Publication 1509, 14th Edition, Addendum I, December 1998. Table 1 lists the saturation levels and viscosity indices for Class I, II and III base oils. Class IV base oil is polyalphaolefin (PAO). Class V base oils include all other base oils not included in Class I, II, III or IV. Although II, III and IV base oils are preferred for use in the present invention, these preferred base oils are prepared by mixing one or more of the I, II, III, IV and V stocks or base oils. Is also good.

Table 1
Saturation, sulfur and viscosity index of Class I, II and III feedstocks ───
Type Saturation viscosity index
(Determined by ASTM D2007) (ASTM D4294, ASTM D4297
(Determined by sulfur or ASTM D3120)
(Determined by ASTM D2270)
─────────────────────────────────────
I Saturation less than 90% and / or 80 or more, less than 120
Or more than 0.03% sulfur
II Saturation 90% or more and 80 or more, less than 120
0.03% or less sulfur
III Saturation 90% or more and 120 or more
Sulfur 0.03% or less.

  Natural lubricating oils can include animal oils, vegetable oils (eg, rapeseed oil, castor oil and lard oil), petroleum, mineral oil, and oils derived from coal or shale.

Synthetic oils include hydrocarbon oils and halo-substituted hydrocarbon oils, such as polymerized and copolymerized olefins, alkylbenzenes, polyphenyls, alkylated diphenyl ethers, alkylated diphenyl sulfides, and derivatives, analogs and homologs thereof. Can be mentioned. Examples of the synthetic lubricating oil include alkylene oxide polymers, true copolymers, copolymers, and derivatives thereof in which terminal hydroxyl groups are modified by esterification, etherification, or the like. Another suitable class of synthetic lubricating oils includes esters of dicarboxylic acids and various alcohols. Esters usable as synthetic oils include those produced from C _{5 to} C ₁₂ monocarboxylic acids, polyols and polyol ethers. Trialkyl phosphate oils, such as those exemplified by tri-n-butyl phosphate and tri-iso-butyl phosphate, are also suitable for use as base oils.

  Silicon-based oils (e.g., polyalkyl, polyaryl, polyalkoxy, or polyaryloxy-siloxane oils and silicate oils) constitute another useful class of synthetic lubricating oils. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, high molecular weight tetrahydrofurans, polyalphaolefins, and the like.

  The base oil may be derived from unrefined, refined, rerefined oils, or mixtures thereof. Unrefined oils are obtained directly from a natural source or synthetic source (eg, coal, shale, or tar sands bitumen) without further purification or treatment. Examples of unrefined oils include shale oil obtained directly from a retort operation, petroleum oil obtained directly from distillation, or ester oil obtained directly from an esterification process, and then each further process Can be used without. Refined oils are the same as unrefined oils except that they have been treated in one or more purification steps to improve one or more properties. Suitable purification techniques include distillation, hydrocracking, hydrotreating, dewaxing, solvent extraction, acid or base extraction, filtration, and percolate, all of which are known to those skilled in the art. . Rerefined oils are obtained by treating used oils in the same manner as used to obtain the refined oils. These rerefined oils, also known as reclaimed or reprocessed oils, are often further processed by additives or by techniques for removal of oil breakdown products.

  Base oils derived from wax hydroisomerization can also be used alone or in combination with the aforementioned natural and / or synthetic base oils. Such wax isomer oils are produced by hydroisomerizing natural or synthetic waxes or mixtures thereof over a hydroisomerization catalyst.

  In the lubricating oil of the present invention, it is preferred to use a major amount of base oil. The major amount of base oil as defined herein comprises 40% by weight or more. Preferred amounts of the base oil comprise at least one of the III, IV and V base oils, from about 40% to about 97% by weight, or preferably at least one of the III, IV and V base oils, about 50% by weight. From about 60% to about 97% by weight, or more preferably from about 60% to about 97% by weight of at least one III, IV and V base oil. (When weight percent is used, it refers to the weight percent of the lubricating oil unless otherwise specified.) A further preferred embodiment of the present invention uses a base oil in an amount comprising about 80% to about 95% by weight of the lubricating oil. Can be contained.

[Ashless dispersant]
The dispersant used in the lubricating oil composition of the present invention is an ashless dispersant such as alkenyl succinimide, alkenyl succinic anhydride and alkenyl succinate, or a mixture of such dispersants.

  Ashless dispersants are broadly classified into several groups. One such group relates to copolymers comprising carboxylic esters having one or more additional polar functions, including amines, amides, imines, imides, hydroxyl carboxyls and the like. These products can be synthesized by copolymerizing a long-chain alkyl acrylate or methacrylate with a monomer having the above function. Examples of such a group include an alkyl methacrylate-vinylpyrrolidinone copolymer and an alkyl methacrylate-dialkylaminoethyl methacrylate copolymer. In addition, high molecular weight amides and polyamides, or esters and polyesters, such as tetraethylene pentaamine, polyvinyl polystearate, and other polysteaamides can be used. Preferred dispersants are N-substituted long chain alkenyl succinimides.

  Alkenyl succinimides are usually derived from the reaction of an alkenyl succinic acid or anhydride with an alkylene polyamine. These compounds are generally considered to have the formula:

Wherein R ¹ is substantially a hydrocarbon group having a molecular weight of about 400 to about 3000, ie, R ¹ is a hydrocarbon group containing about 30 to about 200 carbon atoms, preferably an alkenyl group; R ² , R ³ and R ⁴ are selected from C ₁ -C ₄ alkyl or alkoxy or hydrogen, preferably Is hydrogen; and a is an integer from 0 to about 10, preferably 0 to about 3. The actual reaction product of the alkylene succinic acid or anhydride with the alkylene polyamine consists of a mixture of compounds containing succinic acid and succinimide. However, it is customary to represent this reaction product as a succinimide of the above formula, since this is the main component of the mixture. See, for example, U.S. Patent Nos. 3,022,678, 3,024,237 and 3,172,892.

These N-substituted alkenyl succinimides can be synthesized by reacting maleic anhydride with an olefinic hydrocarbon and then reacting the resulting alkenyl succinic anhydride with an alkylene polyamine. Preferably, the R ¹ group, ie, the alkenyl group, in the above formula is derived from a polymer synthesized from an olefin monomer containing from about 2 to about 5 carbon atoms. Thus, an alkenyl group is obtained by polymerizing an olefin containing from about 2 to about 5 carbon atoms to produce a hydrocarbon having a molecular weight in the range of about 400 to about 3000. Examples of such olefin monomers include ethylene, propylene, 1-butene, 2-butene, isobutene, and mixtures thereof.

  Preferred polyalkyleneamines used to synthesize succinimide have the following formula:

However, b is an integer from 0 to about 10, and Alk, R ^2, R ³ and R ⁴ are as previously defined.

  Alkyleneamines mainly include methyleneamine, ethyleneamine, butyleneamine, propyleneamine, pentyleneamine, hexyleneamine, heptyleneamine, octyleneamine, other polymethyleneamines, and amines such as piperazine and aminoalkyl-substituted piperazine. And higher analogs thereof. Examples thereof include ethylenediamine, triethylenetetraamine, propylenediamine, decamethyldiamine, octamethylenediamine, diheptamethylenetriamine, tripropylenetetraamine, tetraethylenepentamine, trimethylenediamine, pentaethylenehexamine, Methylenetriamine, 2-heptyl-3- (2-aminopropyl) -imidazoline, 4-methylimidazoline, N, N-dimethyl-1,3-propanediamine, 1,3-bis (2-aminoethyl) imidazoline, There are-(2-aminopropyl) -piperazine, 1,4-bis (2-aminoethyl) piperazine, and 2-methyl-1- (2-aminobutyl) piperazine. Such higher order analogs are obtained by condensing two or more of the above-mentioned alkyleneamines and are likewise useful.

  Ethyleneamine is particularly useful. They are described in the Encyclopedia of Chemical Technology, Kirk-Othmer, Vol. 5, p. 898-905, "Ethyleneamine" (Interscience Publishing, New York, 1950).

  "Ethyleneamine" is used in its inclusive sense, indicating a class of polyamines most of which fall into the structure below. Here, c is an integer of 1 to about 10.

_{H 2 N (CH 2 CH 2} NH) C H

  Accordingly, examples thereof include ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and pentaethylenehexamine.

  Examples of the “alkenyl succinimide” include, for example, a post-treatment method containing ethylene carbonate and boric acid disclosed in U.S. Pat. Nos. 4,612,132 (Warenberg, et al.) And 4,746,446 (Warenberg, et al.); Succinimides post-treated by other post-treatment methods may be mentioned, and the disclosures thereof are all described herein.

  In the lubricating oil composition of the present invention, it is preferable to use both succinimide treated with ethylene carbonate and succinimide treated with boric acid in a weight ratio of about 0.3 to about 0.5. The ethylene carbonate treated ashless and borated ashless acidulants may be included in the lubricating oil composition in a total amount of from about 4.0 to about 10% by weight based on the total weight of the lubricating oil composition. preferable.

  The weight range of the ashless acid agent that has been subjected to ethylene carbonate treatment is preferably about 3.0 to about 7.0% by weight, preferably about 4.0 to about 6.0% by weight, and more preferably About 4.5 to about 5.5% by weight.

  The weight range of the borated ashless acid agent is preferably from about 2.0 to about 5.0% by weight, preferably from about 2.5 to about 3.5% by weight.

  The combination of the two succinimides provides better cleanliness and soot dispersibility than when either the carbonated succinimide or the borated succinimide is used alone.

[Metal-containing detergent]
The detergent used in the lubricating oil composition of the present invention is a metal-containing detergent. There are many substances that are suitable for the purpose of the present invention. These materials may include phenates (high or overbased), overbased phenates stearate, phenolates, salicylates, phosphonates, thiophosphonates and sulfonates, and mixtures thereof. Preferably, a sulfonate such as a high overbased sulfonate, a low overbased sulfonate, or a phenoxy sulfonate is used. Further, sulfonic acid itself can be used.

  Preferably, the sulfonate detergent is an alkali or alkaline earth metal salt of a hydrocarbon sulfonic acid having about 15 to about 200 carbon atoms. "Sulfonates" preferably include salts of sulfonic acids derived from petroleum products. Such acids are well-known in the art. It can be obtained by treating petroleum products with sulfuric acid or sulfur trioxide. The acid thus obtained is known as petroleum sulfonic acid and its salt is known as petroleum sulphonate. Most sulfonated petroleum products contain oil solubilized hydrocarbon groups. The meaning of "sulfonate" also includes salts of the sulfonic acids of the synthetic alkylaryl compounds. These acids are also synthesized by treating the alkylaryl compound with sulfuric acid or sulfur trioxide. At least one alkyl substituent on the aryl ring is an oil solubilizing group as described above. The acid thus obtained is known as an alkylaryl sulphonic acid and its salt is known as an alkylaryl sulphonate. Sulfonates in which the alkyl is straight-chain are known linear alkylaryl sulfonates.

  The acid obtained by sulfonation is converted to a metal salt by neutralization with a basic and reactive alkali or alkaline earth metal compound to produce a Group I or Group II metal sulfonate. Generally, the acid is neutralized with an alkali metal base. The alkaline earth metal salt is obtained by metathesis from the alkali metal salt. Alternatively, the sulfonic acid can be directly neutralized with an alkaline earth metal base. Thereby, the sulfonate can be overbased. Preferably, it is overbased for the purposes of the present invention. Overbased materials and methods of making such materials are well known to those skilled in the art. See, for example, U.S. Patent No. 3,496,105 (Rousseur), issued February 17, 1970, especially columns 3 and 4.

  The sulfonate is present in the oil dispersion in the form of an alkali and / or alkaline earth metal salt or a mixture thereof. Alkali metals include lithium, sodium and potassium. Alkaline earth metals include barium, magnesium and calcium, of which the latter two are preferred.

  However, particular preference is given to the extraction of salts of petroleum sulfonic acids, in particular various hydrocarbon fractions such as lubricating oil fractions, and hydrocarbon oils with selected solvents, due to their wide availability. Is a salt of petroleum sulfonic acid obtained by sulfonating an aromatic-rich extract, which is optionally alkylated by reaction with an olefin or alkyl chloride using an alkylation catalyst prior to sulfonation. You may. Further, it is a salt of an organic polysulfonic acid such as benzenedisulfonic acid, which may or may not be alkylated.

  Preferred salts for use in the present invention are salts of alkylated aromatic sulfonic acids wherein the alkyl group (s) contains at least about 8 carbon atoms, for example, about 8 to about 22 carbon atoms. Another preferred group of sulfonate starting materials are aliphatic substituted cyclic sulfonic acids wherein the aliphatic substituent (s) contains at least about 12 carbon atoms in total, such as alkyl aryl sulfonic acids, alkyl cycloaliphatic sulfonic acids , Alkyl heterocyclic sulfonic acids, and aliphatic sulfonic acids wherein the aliphatic group (s) contains at least about 12 total carbon atoms. Specific examples of these oil-soluble sulfonic acids include petroleum sulfonic acids, mono- and polywax substituted naphthalene sulfonic acids, substituted sulfonic acids such as cetyl benzene sulfonic acid and cetyl phenyl sulfonic acid, and aliphatic sulfonic acids such as paraffin wax sulfonic acid. Examples include acids, hydroxy-substituted paraffin wax sulfonic acids, etc., alicyclic sulfonic acids, petroleum naphthalene sulfonic acids, cetyl cyclopentyl sulfonic acids, and mono- and poly-wax-substituted cyclohexyl sulfonic acids. "Petroleum sulfonic acid" is meant to include all sulfonic acids derived directly from petroleum products.

  Representative Group II metal sulfonates suitable for use in the present invention include the following metal sulfonates: calcium white oil benzene sulfonate, barium white oil benzene sulfonate, magnesium white oil benzene sulfonate, calcium disulfide. Polypropene benzene sulfonate, barium dipolypropene benzene sulfonate, magnesium dipolypropene benzene sulfonate, calcium mahogany petroleum sulfonate, barium mahogany petroleum sulfonate, magnesium mahogany petroleum sulfonate, calcium triacontyl sulfonate, magnesium triacontyl sulfonate, calcium lauryl sulfonate, Barium lauryl sulfonate, magnesium lauryl sulf Sulfonate and the like.

  The lubricating oil composition of the present invention can use a high overbased and low overbased metal-containing detergent, that is, a metal sulfonate. The high overbased metal-containing detergent generally ranges from about 1.0 to about 3.0% by weight, based on the total weight of the lubricating oil composition, and preferably from about 1.4 to about 1.8% by weight. % And the total base number (TBN) is from about 5.7 to about 7.4. The low overbased metal-containing detergent generally ranges from about 0.2 to about 6.0% by weight, preferably from about 0.3 to about 0.5% by weight, based on the total weight of the lubricating oil composition. % And the TBN is from about 0.5 to about 0.9.

[Phosphorus-containing compound]
The phosphorus-containing compound used in the lubricating oil composition of the present invention may be a metal dithiophosphate, a phosphoric ester (phosphate ester, phosphonate ester, phosphinate ester, phosphine oxide, phosphite ester, phosphonite ester, phosphine sulfite). Acid esters and phosphines, etc.), amine phosphates and phosphinates, sulfur-containing phosphorus esters including phosphorus monothionates and phosphodithionates, phosphorus amides, phosphonamides and the like, all of which are known in the art. well known. The phosphorus-containing compound is more preferably a metal dithiophosphate, and even more preferably zinc dithiophosphate. Most preferably the phosphorus-containing compound is a zinc dialkyl dithiophosphate wherein the alkyl group is selected from branched or straight chain carbon groups of C ₃ -C ₁₃ independently (including mixtures thereof). More preferably, the phosphorus-containing compound is a zinc dialkyldithiophosphate made from a mixture of secondary alcohols having an average carbon chain length between about 3 and about 6 carbon atoms.

  Metal dithiophosphates are characterized by Formula I:

Wherein R ⁵ is independently a hydrocarbon group containing from about 3 to about 13 carbon atoms, M is a metal, and d is an integer equal to the valency of M.

In the dithiophosphate (or when described elsewhere in this application) of the hydrocarbon group R ^5, the alkyl group of C ₃ -C _13, cycloalkyl group of _{C 3 ~C 13, C 7 ~C} 13 You can aralkyl or alkaryl group of C ₇ ~C _13,, or a hydrocarbon group having substantially the same structure. By “substantially hydrocarbon” is meant a hydrocarbon containing substituents that do not substantially affect the hydrocarbon properties of the group, for example, ethers, esters, nitro or halogens.

Examples of the alkyl group include isopropyl, isobutyl, n-butyl, sec-butyl, various amyl groups, n-hexyl, methyl isobutyl carbyl, heptyl, 2-ethylhexyl, diisobutyl, isooctyl, nonyl, behenyl, decyl, dodecyl , Tridecyl and the like. Examples of lower alkylphenyl groups include butylphenyl, amylphenyl, heptylphenyl and the like. Cycloalkyl groups can be used as well, including primarily cyclohexyl groups and lower alkyl-cyclohexyl groups. Numerous substituted hydrocarbon groups can also be used, for example, chlorophenyl, dichlorophenyl and dichlorodecyl. In another embodiment, at least one R ⁵ group is an isopropyl group or a secondary butyl group. In yet another aspect, both R ⁵ groups are secondary alkyl groups.

  Phosphodithioic acids from which metal salts that can be used in the present invention are synthesized are well known. Examples of dihydrocarbon phosphorodithioic acids and metal salts, and methods of making such acids and salts, can be found, for example, in U.S. Patent Nos. 4,263,150, 4,289,635, 4,308,154 and 4,417,990. The disclosure content of these patents is also described in this specification as a reference.

  Phosphodithioic acid is generally synthesized by the reaction of phosphorus pentasulfide with an alcohol or phenol or a mixture of alcohol and / or phenol. The reaction comprises 4 moles of alcohol or phenol per mole of phosphorus pentasulfide and can be carried out in a temperature range from about 50 ° C to about 200 ° C. Thus, the synthesis of O, O-di-n-hexylphosphorodithioic acid involves reacting phosphorus pentasulfide with 4 moles of n-hexyl alcohol at about 100 ° C. for about 2 hours. Hydrogen sulfide is liberated and the residue is the above-mentioned acid. The synthesis of the metal salt of the acid results from a reaction with a metal oxide. Simply mixing and heating the two reactants is sufficient to cause the reaction to occur, and the resulting product is sufficiently pure for the purposes of the present invention.

  Examples of the metal dihydrocarbon dithiophosphate that can be used in the present invention include salts containing a Group I metal, a Group II metal, zinc, aluminum, lead, tin, molybdenum, manganese, cobalt and nickel, or a mixture thereof. it can. Group II metals, zinc, aluminum, tin, iron, cobalt, lead, molybdenum, manganese, nickel and copper are among the preferred metals. Zinc and copper are particularly useful metals, alone or in combination. Particularly preferred is zinc. In one embodiment, in the lubricant composition of the present invention, examples of the metal compound capable of reacting with an acid include lithium oxide, lithium hydroxide, sodium hydroxide, sodium carbonate, potassium hydroxide, potassium carbonate, silver oxide, and oxidized metal. Magnesium, magnesium hydroxide, calcium oxide, zinc hydroxide, zinc oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide, barium oxide, aluminum oxide, iron carbonate, copper hydroxide, lead hydroxide, tin butylated, hydroxide Cobalt, nickel hydroxide, nickel carbonate and the like can be mentioned.

  In certain instances, the introduction of a small amount of metal acetate or acetic acid (glacial acetic acid) that binds certain components, such as a metal reactant, drives the reaction to a good product. For example, the use of up to about 5% zinc acetate in combination with the required amount of zinc oxide promotes the formation of zinc phosphodithionate.

The alkyl group R ⁵ a preferred embodiment, is derived secondary alcohols such as isopropyl alcohol, secondary butyl alcohol, 2-pentanol, 4-methyl-2-pentanol, 2-hexanol, 3-hexanol, etc. . Preferably R ⁵ is a mixture of secondary alcohols derived from e.g. a 2-butanol 4-methyl-2-pentanol. Particularly preferred R ⁵ is derived from the mixture containing the remainder of the 4-methyl-2-pentanol and about 65 to about 75 wt% of 2-butanol.

  Particularly useful metal phosphodithionates can be prepared from phosphorodithioic acid, which in turn is synthesized from the reaction of phosphorus pentasulfide with a mixture of alcohols. Furthermore, the use of such a mixture allows the use of inexpensive alcohols which do not themselves produce oil-soluble phosphorodithioic acid.

  Mixtures of metal salts of dihydrocarbon dithiophosphoric acids that can be used are obtained by reacting phosphorus pentasulfide with a mixture of (a) isopropyl or secondary butyl alcohol and (b) an alcohol containing at least about 5 carbon atoms. However, at least about 10 mole%, preferably about 20 or about 25 mole% of the alcohol in the mixture is isopropyl alcohol, secondary butyl alcohol or a mixture thereof.

  Thus, a mixture of isopropyl and hexyl alcohol can be used to produce highly effective oil-soluble metal phosphodithionates. For the same reason, mixtures of phosphorodithioic acids can also react with metal compounds to form less expensive oil-soluble salts.

  The mixture of alcohols may be a mixture of different primary alcohols, a mixture of different secondary alcohols, or a mixture of primary and secondary alcohols. Examples of mixtures which can be used are n-butanol and n-octanol, n-pentanol and 2-ethyl-1-hexanol, isobutanol and n-hexanol, isobutanol and isoamyl alcohol, isopropanol and 4-methyl-2- Pentanol, isopropanol and sec-butyl alcohol, isopropanol and isooctyl alcohol, sec-butyl alcohol and 4-methyl-2-pentanol, and the like can be given. A particularly useful alcohol mixture is a mixture of secondary alcohols containing at least about 20 mole%, preferably at least about 40 mole%, of isopropyl alcohol. In a preferred embodiment, at least about 75 mol% of sec-butyl alcohol is used and is preferably combined with 4-methyl-2-pentanol, and most preferably also with zinc metal.

  Particularly preferred metal dihydrocarbon phosphodithionates include zinc dithiophosphate. Patents describing the production of such zinc dithiophosphates include U.S. Pat. Nos. 2,680,123, 300,822, 3,115,075, 3,385,791, 4,377,527, 4,495,075 and 4,778,906. . Each of these patents is also incorporated herein by reference.

  The amount of the phosphorus-containing compound in the lubricating oil composition of the present invention ranges from about 0.1 to about 4% by weight, based on the total weight of the lubricating oil composition, preferably from about 0.1 to about 2.0. %, Most preferably in the range of about 0.4 to about 0.8% by weight.

[Nitrogen-containing ashless antioxidant]
The nitrogen-containing ashless antioxidant of the present invention is of the diphenylamine type. Examples of diphenylamine-type antioxidants include, but are not limited to, alkylated diphenylamine, phenyl-α-naphthylamine, and alkylated-α-naphthylamine. Preferably, the nitrogen-containing ashless antioxidant is an alkylated diphenylamine such as, for example, a dialkylated diphenylamine. The nitrogen-containing ashless antioxidant is generally incorporated into the lubricating oil composition in an amount from about 0.5 to about 3.0% by weight, based on the total weight of the lubricating oil composition, and preferably from about 1.0 to about It is introduced in an amount of 2.0% by weight.

[Alkylthiocarbamoyl compound]
The alkylthiocarbamoyl compound of the lubricating oil of the present invention can be represented by the following formula:

Wherein R ⁶ , R ⁷ , R ⁸ and R ⁹ may be the same or different and each represents an alkyl group having 1 to about 18 carbon atoms, and (X) represents S, S—S, _{S-CH 2 -S, S-} CH 2 -CH 2 -S, S-CH 2 -CH 2 -CH 2 -S or _{S-CH 2 -CH (CH 3} ), represents a -CH ₂ -S. Preferably, R ⁶ , R ⁷ , R ⁸ and R ⁹ are independently selected from an alkyl group having 1 to about 6 carbon atoms. More preferably, the dithiocarbamate compound is methylene bis (dibutyldithiocarbamate).

  The lubricating oil compositions of the present invention generally have from about 0.3 to about 1.0% by weight of the alkylthiocarbamoyl compound based on the total weight of the lubricating oil composition, preferably from about 0.3 to about 0.1%. 7% by weight, most preferably from about 0.4 to about 0.6% by weight.

[Molybdenum-succinimide complex (composite)]
The molybdenum-succinimide complex used in the present invention can be generally regarded as a molybdenum complex of a basic nitrogen compound. Such molybdenum / sulfur complexes are known in the art and are described, for example, in US Pat. No. 4,263,152 (King, et al.), The disclosure of which is incorporated herein by reference.

  The structure of the molybdenum compositions used in the present invention is not known with certainty; however, the molybdenum compositions are complexed with one or more nitrogen atoms of the basic nitrogen-containing compound used by the molybdenum to produce these compositions. It is believed to be a compound that is formed or is a salt thereof, the valence of molybdenum being filled with oxygen and / or sulfur atoms.

The molybdenum compounds used to produce the molybdenum and molybdenum / sulfur complexes used in the present invention are acidic molybdenum compounds. By acidic is meant that the molybdenum compound reacts with the basic nitrogen compound as measured by ASTM test D-664 or D-2896 titration. Generally, these molybdenum compounds are hexavalent and are represented by the following compositions: molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate and other alkali metal molybdates, and other molybdenum such as hydrogen salts Such as sodium hydrogen molybdate, MoOCl ₄ , MoO ₂ Br ₂ , Mo ₂ O ₃ Cl ₆ , molybdenum trioxide, or similar acidic molybdenum compounds. Preferred acidic molybdenum compounds are molybdate, ammonium molybdate and alkali metal molybdates. Particularly preferred are molybdic acid and ammonium molybdate.

  The basic nitrogen compound used to make the molybdenum complex has at least one basic nitrogen and is preferably oil-soluble. Representative examples of such compositions include succinimides, carboxamides, hydrocarbon monoamines, hydrocarbon polyamines, Mannich bases, phosphoramides, thiolinamides, phosphonamides, dispersant type viscosity index improvers, and the like. There is a mixture of Any nitrogen-containing composition may be post-treated using methods known in the art, for example with boron, as long as the composition continues to contain basic nitrogen. These post-treatments apply in particular to succinimide and Mannich base compositions.

  Mono and polysuccinimides that can be used to make the above molybdenum complexes are disclosed in numerous references and are well known in the art. Certain basic classes of succinimides and related materials encompassed by the term "succinimide" in the art are taught and disclosed in U.S. Patent Nos. 3,219,666, 3,172,892 and 3,272,746. The contents are also described in this specification for reference. "Succinimide" is understood in the art to include a number of amides, imides, and amidine species that may be formed. However, the main product is succinimide, which term is generally accepted as meaning the product of the reaction of an alkenyl-substituted succinic acid or anhydride with a nitrogen-containing compound. Preferred succinimides are succinimides which are commercially available and thus are synthesized from a hydrocarbon succinic anhydride wherein the hydrocarbon group contains from about 24 to about 350 carbon atoms and ethyleneamine, wherein the ethylene is Amines are particularly characterized by ethylenediamine, diethylenetriamine, triethylenetetraamine and tetraethylenepentamine. Particularly preferred are succinimides such as those synthesized from polyisobutenyl succinic anhydrides having from about 70 to about 128 carbon atoms and tetraethylenepentamine or triethylenetetraamine or mixtures thereof.

  The term "succinimide" also includes a hydrocarbon succinic acid or anhydride and a polysecondary amine containing at least one tertiary amino nitrogen in addition to two or more secondary amino groups. Oligomers are also included. Typically, the average molecular weight of the composition will be between about 1500 and about 50,000. A typical compound is a compound synthesized by reacting polyisobutenyl succinic anhydride with ethylene dipiperazine.

Carboxamide compositions are also suitable starting materials for preparing the molybdenum complexes used in the present invention. Representative examples of such compounds are those disclosed in U.S. Pat. No. 3,405,064, the disclosure of which is incorporated herein by reference. These compositions typically have at least about 12 to about 350 aliphatic carbon atoms in the main fatty chain and, optionally, a carboxylic acid or anhydride having sufficient aliphatic side groups to make the molecule oil-soluble. The compound or its ester is reacted with a hydrocarbon polyamine such as an amine or ethyleneamine to produce a mono- or polycarboxylic amide. Preferred are carboxylic acids of the formula (1): R ¹⁰ COOH where R ¹⁰ is C ₁₂ -C ₂₀ alkyl, or a polycarboxylic acid wherein the acid and the polyisobutenyl group contain from about 72 to about 128 carbon atoms. Mixtures with isobutenylcarboxylic acid, and (2) amides such as those synthesized from ethyleneamines, especially triethylenetetraamine or tetraethylenepentamine or mixtures thereof.

  Another class of compounds that can be used in the present invention are hydrocarbon monoamines and hydrocarbon polyamines, preferably of the type disclosed in U.S. Pat. No. 3,574,576, the disclosure of which is incorporated herein by reference. I do. Preferably, the hydrocarbon group is an alkyl or an olefin having one or two sites of unsaturation and usually contains from about 9 to about 350, preferably from about 20 to about 200, carbon atoms. Particularly preferred hydrocarbon polyamines include, for example, polyisobutenyl chloride and polyalkylene polyamines such as ethyleneamine, specifically ethylenediamine, diethylenetriamine, tetraethylenepentamine, 2-aminoethylpiperazine, 1,3-propylenediamine and 1 , 2-propylenediamine and the like.

Another class of compounds that can be used to provide basic nitrogen is the class of Mannich base compositions. These compositions are synthesized from phenols, or alkylphenols of C ₉ -C _200, aldehydes such as formaldehyde or formaldehyde precursor such as paraformaldehyde, and an amine compound. The amine may be a monoamine or a polyamine, and typical compositions are synthesized from alkylamines, such as methylamine or ethyleneamine, such as diethylenetriamine or tetraethylenepentamine. The phenolic material may be sulfurized, preferred are alkylphenols dodecylphenol or C ₈₀ -C _100. Representative Mannich bases that can be used in the present invention are disclosed in U.S. Pat. Nos. 4,157,309 and 3,649,229, 3,368,972, and 3,539,663, the disclosures of which are also incorporated herein by reference. . The last referenced patent, at least about 50 carbon atoms, preferably alkyl phenols of about 50 to about 200 carbon atoms with formaldehyde and an alkylene polyamine HN (ANH) _e H (provided that, A is from about 2 carbon atoms About 6 saturated divalent alkyl hydrocarbons, e is from 1 to about 10), and the condensate of the alkylene polyamine may be further reacted with urea or thiourea. It is disclosed. The utility of these Mannich bases as starting materials for making lubricating oil additives can often be significantly improved by treating the Mannich bases using conventional techniques to introduce boron into the composition.

  Another class of compositions that can be used to make the molybdenum complexes used in the present invention are phosphoramides and phosphonamides, such as those disclosed in U.S. Pat. Nos. 3,909,430 and 3,968,157, the disclosures of which are hereby incorporated by reference. Is also described herein as a reference. These compositions can be synthesized by forming a phosphorus compound having at least one PN bond. For example, it can be synthesized by reacting phosphorus oxychloride with a hydrocarbon diol in the presence of a monoamine, or by reacting phosphorus oxychloride with a difunctional secondary amine and a monofunctional amine. Thiolinamides are unsaturated hydrocarbon compounds containing from about 2 to about 450 or more carbon atoms, such as polyethylene, polyisobutylene, polypropylene, ethylene, 1-hexene, 1,3-hexadiene, isobutylene and 4-methyl- Reacting 1-pentene and the like with phosphorus pentasulfide and the above-mentioned nitrogen-containing compounds, especially alkylamines, alkyldiamines, alkylpolyamines or alkyleneamines such as ethylenediamine, diethylenetriamine, triethylenetetraamine and tetraethylenepentamine. Can be synthesized by

  Another class of nitrogen-containing compositions that can be used to produce the molybdenum complexes used in the present invention include so-called dispersant type viscosity index improvers (VI improvers). These VI improvers are usually derived from hydrocarbon polymers, especially ethylene and / or propylene, optionally containing additional units derived from one or more comonomers such as cycloaliphatic or aliphatic olefins or diolefins. Synthesized by functionalizing the polymer. The functionalization can be carried out by various methods which introduce a reactive site (s), usually having at least one oxygen atom, into the polymer. Next, the polymer is brought into contact with a nitrogen-containing raw material to introduce a nitrogen-containing functional group into the main chain of the polymer. Commonly used nitrogen sources include any basic nitrogen compound, especially the nitrogen-containing compounds and compositions described above. Preferred nitrogen sources are alkyleneamines such as ethyleneamine, alkylamines and Mannich bases.

  Preferred basic nitrogen compounds for use in the present invention are succinimides, carboxamides and Mannich bases. More preferred are succinimides having an average molecular weight of about 1000 or about 1300 or about 2300, and mixtures thereof. Such succinimides can be post-treated with boron or ethylene carbonate, as is known in the art.

The molybdenum complex of the present invention is preferably sulfurized. Typical sulfur raw materials for producing the molybdenum / sulfur complex used in the present invention include sulfur, hydrogen sulfide, sulfur monochloride, sulfur dichloride, phosphorus pentasulfide, R ¹¹ S _f (where R ¹¹ is Inorganic sulfides and polysulfides such as hydrocarbon groups, preferably C ₁ -C ₄₀ alkyl, and f is at least 2), (NH ₄ ) ₂ S _g , where g is at least 1. And thioacetamides, thioureas, and mercaptans of the formula R ¹¹ SH, where R ¹¹ is as defined above. Conventional sulfur-containing antioxidants, such as sulfurized and polysulfided waxes, sulfurized olefins, sulfurized carboxylic acids and esters and sulfurized ester olefins, and sulfurized alkylphenols and their metal salts can also be used as the sulfurizing agent.

Sulfurized fatty acid esters are synthesized by reacting sulfur, sulfur monochloride and / or sulfur dichloride with unsaturated fatty acid esters at elevated temperatures. Exemplary esters, unsaturated fatty acids of C ₈ -C _24, for example, palmitoleic acid, oleic acid, ricinoleic acid, petroselinic acid, vaccenic acid, linoleic acid, linolenic acid, oleostearic, licanic, Paranarin acid , mention may be made of sufficient acid, gadoleic acid, arachidonic acid, the alkyl esters of C ₁ -C _20, such as cetoleic acid. Particularly good results are obtained with mixed unsaturated fatty acid esters, for example those obtained from animal fats and vegetable oils such as tall oil, linseed oil, olive oil, castor oil, peanut oil, rapeseed oil, fish oil and sperm whale oil. .

  Examples of fatty acid esters include lauryl tartrate, methyl oleate, ethyl oleate, lauryl oleate, cetyl oleate, cetyl linoleate, lauryl ricinoleate, oleyl linoleate, oleyl stearate, and alkyl glycerides. Can be mentioned.

Crosslinked sulfurized ester olefins, such as C ₁₀ -C and olefins _25, alkyl or alkenyl alcohols of fatty acid esters of fatty acids and C ₁₀ -C ₂₅ in C ₁₀ -C ₂₅ (provided that fatty acids and / or alcohols are unsaturated) Sulfidation mixtures with can also be used.

Sulfurized olefins, low molecular weight polyolefin derived from the olefin or of C ₃ -C _6, sulfur is synthesized by the reaction of a sulfur-containing compound such as sulfur, sulfur monochloride and / or sulfur dichloride.

  Aromatic sulfides and alkyl sulfides, such as dibenzyl sulfide, dixyl sulfide, dicetyl sulfide, sulfurized and polyparasulfide waxes, and cracked wax-sulfided olefins can also be used. They can be synthesized by treating a starting material such as an olefinically unsaturated compound with sulfur, sulfur monochloride and sulfur dichloride. Particularly preferred are the paraffin wax thiomers described in U.S. Pat. No. 2,346,156.

  Sulfurized alkylphenols and their metal salts include compounds such as sulfurized dodecylphenol and its calcium salts. Alkyl groups usually contain about 9 to about 300 carbon atoms. The metal salt is preferably a Group I or Group II salt, especially sodium, calcium, magnesium or barium.

Preferred sulfur sources are sulfur, hydrogen sulfide, phosphorus pentasulfide, R ¹² S _h (provided that, R ¹² is a hydrocarbon group, preferably an alkyl of C ₁ -C _10, and h is at least about 3), Mercaptans, wherein R ¹² is C ₁ -C ₁₀ alkyl, inorganic sulfides and polysulfides, thioacetamide, and thiourea. Most preferred sulfur sources are sulfur, hydrogen sulfide, phosphorus pentasulfide, and inorganic sulfides and polysulfides.

  The polarity promoter used in the production of the molybdenum complex used in the present invention promotes the interaction between the acidic molybdenum compound and the basic nitrogen compound. A wide variety of such accelerators are well known to those skilled in the art. Representative accelerators include 1,3-propanediol, 1,4-butane-diol, diethylene glycol, butyl cellosolve, propylene glycol, 1,4-butylene glycol, methyl carbitol, ethanolamine, diethanolamine, N-methyl- There are diethanol-amine, dimethylformamide, N-methylacetamide, dimethylacetamide, methanol, ethylene glycol, dimethylsulfoxide, hexamethyllinamide, tetrahydrofuran, and water. Preferred are water and ethylene glycol. Particularly preferred is water.

Usually, the polar promoter is added separately to the reaction mixture, but especially in the case of water, the polar promoter can be a non-anhydrous starting material component or an acidic one such as (NH ₄ ) ₆ Mo ₇ O ₂₄ .H ₂ O. The molybdenum compound may be present as water of hydration. Further, water may be added as ammonium hydroxide.

  The method for producing the molybdenum complex used in the present invention is to synthesize a solution of an acidic molybdenum precursor and a polar promoter and a basic nitrogen-containing compound with or without a diluent. If necessary, a diluent is used to achieve a suitable viscosity that facilitates stirring. Typical diluents are lubricating oils and liquid compounds containing only carbon and hydrogen. If desired, ammonium hydroxide may be added to the reaction mixture to form a solution of ammonium molybdate. The reaction is carried out at various temperatures, generally from the melting point of the mixture or below to the reflux temperature. Usually at atmospheric pressure, higher or lower pressures can be used if desired. The reaction mixture can optionally be treated with the sulfur source described above at a suitable pressure and temperature such that the sulfur source reacts with the acidic molybdenum and the basic nitrogen compound. In some cases, it is desirable to remove water from the reaction mixture before the reaction with the sulfur source is complete.

  In a preferred and improved method for making the molybdenum complex, the reactor is agitated and heated to a temperature less than or equal to about 120 degrees Celsius, preferably from about 70 degrees Celsius to about 90 degrees Celsius. The molybdenum oxide or other suitable molybdenum source is then charged to the reactor and the temperature is maintained below about 120 degrees Celsius, preferably between about 70 degrees Celsius and about 90 degrees Celsius, until the molybdenum has reacted sufficiently. Remove excess water from the reaction mixture. The method of removal includes, but is not limited to, vacuum distillation or nitrogen while maintaining the reactor temperature at about 120 degrees Celsius or less, preferably between about 70 degrees Celsius and about 90 degrees Celsius. Stripping can be mentioned. To keep the chromaticity of the molybdenum-containing composition low, the temperature during the stripping step is maintained at a temperature of about 120 degrees Celsius or less. Stripping is usually performed at atmospheric pressure, but higher or lower pressures can be used. The stripping step is generally performed for about 0.5 to about 5 hours.

If desired, the reaction mixture is treated with the sulfur source described above at a suitable pressure and at a temperature not exceeding about 120 degrees Celsius, such that the sulfur source reacts with the acidic molybdenum and the basic nitrogen compound. Can be sulfurized. The sulfidation step is generally performed for about 0.5 to about 5 hours, preferably for about 0.5 to about 2 hours. In some cases, it is desirable to remove the polar promoter (water) from the reaction mixture before completion of the reaction with the sulfur source. Molybdenum and molybdenum / sulphur complexes formed in this way are lighter in color (when compared to complexes made at higher temperatures), while having good fuel economy, excellent antioxidant and antiwear properties. Has been maintained. The colors in this example can be more visualized or quantified using a UV spectrophotometer, such as a Perkin-Elmer Lambda 18 UV-visible double beam spectrophotometer. As used herein, this test recorded the visible spectrum of a constant concentration of the molybdenum composition in isooctane solvent. The spectrum represents the absorbance plotted against the wavelength nanometer. The spectrum ranges from the visible region of electromagnetic radiation to the near infrared region (350 nanometers to 900 nanometers). In this test, the darker sample showed a higher absorbance at higher wavelengths at a constant molybdenum concentration.
Preparation of the sample for color measurement consisted of diluting the molybdenum-containing composition with isooctane to a constant molybdenum concentration of 0.00025 g molybdenum per gram of the molybdenum-containing composition / isooctane mixture. Prior to sample measurement, the spectrophotometer is normalized by scanning air to air. A UV-visible spectrum of about 350 nanometers to about 900 nanometers is obtained using a 1 cm optical path length quartz cell, relative to atmospheric standards. The spectral bias is corrected by setting the absorbance at 867 nanometers to zero. Next, the absorbance of the sample at a wavelength of 350 nanometers is determined.

  The properties of these novel molybdenum / sulfur complexes are disclosed in U.S. patent application Ser. No. 10 / 159,446, filed May 31, 2002, entitled "Molybdenum-Containing Compositions with Reduced Colors and Methods of Making Same". , The contents of which are all described herein as references.

  In the reaction mixture, the ratio of molybdenum compound to basic nitrogen compound is not critical, however, as the amount of molybdenum relative to basic nitrogen increases, filtration of the product becomes more difficult. Since the molybdenum component is probably oligomerized, it is advantageous to add as much molybdenum as can easily be retained in the composition. Usually, the reaction mixture will contain from about 0.01 to about 2.00 molybdenum atoms per basic nitrogen atom. Preferably, about 0.3 to about 1.0, most preferably about 0.4 to about 0.7, molybdenum per basic nitrogen atom is added to the reaction mixture.

  When optionally sulfided, the molybdenum sulfide-containing composition can generally be considered as a sulfur / molybdenum complex of a basic nitrogen dispersant compound, wherein the weight ratio of sulfur to molybdenum is preferably about (0.01 to 1). 0.0) to 1, more preferably about (0.05 to 0.5) to 1 and the weight ratio of nitrogen to molybdenum is about (1 to 10) to 1, more preferably about 1 to 10. (2-5) is one. With very low sulfur introduction, the weight ratio of sulfur to molybdenum can be about (0.01-0.08) to 1.

  The sulfurized and unsulfurized molybdenum-succinimide complexes of the present invention are generally used in the lubricating oil compositions of the present invention in amounts of about 0.1 to about 1.5% by weight, more preferably about 0.5 to about 1.5%. It is used in an amount of 1.0% by weight.

[Other additives]
The following additive components are some examples of components that can be preferably used in the present invention. Examples of these additives are set forth to illustrate the invention and do not limit the invention:

(1) Metal detergents: sulfurized or unsulfurized alkyl or alkenyl phenates, alkyl or alkenyl aromatic sulfonates, sulfurized or unsulfurized metal salts of polyhydroxyalkyl or alkenyl aromatic compounds, alkyl or alkenyl hydroxyaromatic sulfonates, sulfurized Or unsulfurized alkyl or alkenyl naphthenates, metal salts of alkanolic acids, metal salts of alkyl or alkenyl polyacids, and chemical and physical mixtures thereof.

(2) Antioxidants: Antioxidants reduce the tendency of mineral oils to degrade during service, which is due to oxidation products such as sludge and varnish-like deposits on metal surfaces, and viscosity. Proven by an increase in Examples of antioxidants that can be used in the present invention include, but are not limited to, phenolic (phenolic) antioxidants 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-tert-butylphenol), 4,4'-butylidene-bis (3-methyl-6-tert-butylphenol), 4,4'-isopropylidene-bis (2,6-di-tert-butylphenol) , 2,2'-methylene-bis (4-methyl-6-nonylphenol), 2,2'-isobutylidene-bis (4,6-dimethylphenol), 2,2'-methylene-bis (4-methyl-6 − Clohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6 -Di-tert-I-dimethylamino-p-cresol, 2,6-di-tert-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-tert-butylbenzyl) -sulfide, and bis (3,5-di- -Tert-butyl-4-hydroxybenzyl) -sulfide. Other types of antioxidants include metal dithiocarbamates (eg, zinc dithiocarbamate), and methylene bis (dibutyldithiocarbamate).

(3) Antiwear agents: As the name implies, these additives reduce wear of moving metal parts. Examples of such additives include, but are not limited to, phosphates, phosphites, carbamates, esters, sulfur-containing compounds, and molybdenum complexes.

(4) Rust inhibitor additive (rust inhibitor)
a) Nonionic polyoxyethylene surfactant: polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl Ether, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate, and polyethylene glycol monooleate.
b) Other compounds: stearic acid and other fatty acids, dicarboxylic acids, metal soaps, fatty acid amine salts, metal salts of heavy sulfonic acids, partial carboxylic acid esters of polyhydric alcohols, and phosphate esters.

(5) Demulsifiers: adducts of alkylphenol and ethylene oxide, polyoxyethylene alkyl ethers, and polyoxyethylene sorbitan esters.

(6) Extreme pressure agent (EP agent): zinc dialkyldithiophosphate (primary alkyl, secondary alkyl and aryl type), sulfurized oil, diphenylsulfide, methyltrichlorostearate, chlorinated naphthalene, fluorinated alkylpolysiloxane , And lead naphthenate.

(7) Friction modifiers: fatty alcohols, fatty acids, amines, borated esters, and other esters.

(8) Multifunctional additives: oxymolybdenum sulfide dithiocarbamate, oxymolybdenum sulfide organic phosphorus dithioate, oxymolybdenum monoglyceride, oxymolybdenum dielate amide, amine-molybdenum complex compound, and sulfur-containing molybdenum complex compound.

(9) Viscosity index improver: polymethacrylate type polymer, ethylene-propylene copolymer, styrene-isoprene copolymer, hydrated styrene-isoprene copolymer, polyisobutylene, and dispersant type viscosity index improver.

(10) Pour point depressant: polymethyl methacrylate.

(11) Antifoaming agent: alkyl methacrylate polymer and dimethyl silicone polymer.

  The invention is further described by the following examples, which illustrate particularly advantageous method embodiments. It should be noted that the examples are described for describing the present invention, and the present invention is not limited thereto. This application is intended to cover various changes and substitutions that can be made by those skilled in the art without departing from the spirit and scope of the appended claims.

[Example 1]
The low phosphorus lubricating oil composition of the present invention was prepared by blending the following components together at room temperature to obtain a SAE 0W-20 viscosity grade formulation.

Table 2 Lubricating oil composition II
Additive component weight% of additive component
Oil 1 Oil 2 Oil 3 Oil 4 Oil 5 Oil 6
─────────────────────────────────────
EC processing 5.2 5.2 5.2 5.2 5.2 5.2 5.2
Ashless acid agent Boration treatment 3.2 3.2 3.2 3.2 3.2 3.2
Ashless acid detergent LOB detergent 0.3 0.3 0.3 0.3 0.3 0.3
HOB detergent 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6
Phosphorus-containing compound 0.7 0.7 0.7 0.7 0.7 0.7 0.7
Nitrogen content 1.5 1.5 1.5 1.5 1.5 1.5 1.5
Ashless antioxidant Alkylthio 00 0.5 0.5 0.5 0.5
Carbamoyl compound Molybdenum-0.7 0.7 0.7 0.7 0.7 0.7 0.7
Succinimide complex Base oil:
Class III 0 100 0 0 100 0
PAO (Class IV) 100 0 90 100 0 90
Ester (Class V) 0 0 10 0 0 10
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Other additives make up the balance of the lubricating oil composition.

[Comparative Example A]
The low phosphorus lubricating oil composition was compared to a commercially available long-term recognized lubricating oil (trade name: Mobil 1). This reference oil is a fully formulated synthetic engine oil for passenger cars that is formulated to SAE 5W-30 viscosity and meets API SJ / CF standards. This competing commercial formulation was the minimum acceptable performance target for the long-term drainage oil described above. The bench test described below was performed on two identical reference oils, and the average results were compared with the low phosphorus lubricating oils of the present invention.

Example 2 Rotating Bomb Oxidation Test A rotating bomb oxidation test (RBOT) was performed according to a standard test method specified in ASTM D2272.

  The test oil, water and copper catalyst coil contained in the capped glass container were placed in a container equipped with a pressure gauge. The vessel is filled with oxygen to a gauge pressure of 620 kPa (90 psi, 6.2 bar), the vessel is placed in a constant temperature oil bath set at 150 ° C. and rotated along the axis at an angle of 30 degrees from horizontal at 100 rpm. Was. The fraction required to reach a particular drop in gauge pressure (25 psi) was the oil oxidation stability of the test sample. The longer the time, the better the oxidation stability.

  The study report provided a statement of precision and deviation (95% confidence). The data range of the result in RR: D02-1409 was 30 to 1000 minutes.

Reproducibility-"The difference between successful test results obtained on the same test material under the same operating conditions, by the same operator, using the same equipment, is the difference between the long-term tests and the standard test method. According to the correct operation, only one out of 20 attempts to exceed the following values:
0.22X
Here, X represents an average value. "

  Table 3 shows the results. The time to 25 psi pressure drop was 100 minutes with the reference oil. However, the low phosphorus lubricating oil of the present invention lasted significantly longer than the reference oil, indicating improved oxidative stability.

Example 3 Thin Film Oxygen Consumption Test A thin film oxygen consumption test (TFOUT) was performed according to the standard test method specified in ASTM D4742.

  "The test oil was mixed in a glass container with three other liquids used to simulate engine conditions: (1) oxidized / nitrated fuel components, (2) soluble metal naphthenates (lead, copper, iron , Manganese and tin naphthenate), and (3) distilled water.

  The glass container holding the oil mixture was placed in a high pressure reactor equipped with a pressure gauge. The high pressure reactor was sealed, charged with oxygen to a pressure of 620 kPa (90 psig), and placed in a 160 ° C. oil bath at an angle of 30 degrees from horizontal. The high pressure reactor was rotated along the axis at a speed of 100 rpm to form a thin film of oil in the glass vessel, resulting in a relatively large oil-oxygen contact area.

  The pressure in the high pressure reactor was continuously recorded from the start of the test, and the test was terminated when a rapid decrease in pressure in the high pressure reactor was observed. The time elapsed between the time when the high-pressure reactor was placed in the oil bath and the time when the pressure began to decrease rapidly was called the oxidation induction time, and was used as an evaluation of relative oil oxidation stability. . The longer the time, the better the oxidation stability. "

"The difference between successful results obtained for the same test material under the same operating conditions, by the same operator, using the same equipment, is due to the long-running tests and the standard correct operation of the test method. For example, only one out of 20 attempts to exceed the following values:
0.10 (x + 5 minutes)
Where x is the average (min) of repeated tests. "

  Table 3 shows the results. The reference oil lasted approximately 534 minutes before the rapid pressure drop. Oil 3 performed somewhat poorly, while Oils 1, 2 and 4-6 performed well. In particular, Oils 4-6 with additional antiwear / antioxidants were the preferred formulations and performed well.

Example 4 Komatsu Hot Tube Test The Komatsu Hot Tube Test (KHTT) was used for screening engine oils and other oils subjected to high temperatures and quality control of sediment formation performance.

The glass tube was placed inside an aluminum block and a thin air hose was attached to the holder at the bottom of the glass tube. A 5 mL syringe and 12 inches of flexible tubing were filled with the oil sample. The tubing was attached to a holder above the air hose and the oil was steadily introduced into the glass tube. During the test, the heating block causes air to raise the oil in the glass tube. After 16 hours, the glass tubes were removed, rinsed, and evaluated against criteria. Ratings were reported between 0 and 10. Tests were often performed at different temperatures to determine sediment performance over a range of temperature variations. Frequently tested temperatures were between 230 ° C and 330 ° C.
Note: High numbers are preferred and 10 is a totally clean tube.

  Table 3 shows the results. Oils 1-6 scored 6.5-7.0, while the reference oil scored 8.5. While these results correlated only slightly with the reference oil, Oils 1-6 did not provide significant sediment control.

[Example 5] Four-ball fusion test A four-ball fusion test (FBWT) was performed according to a standard test method specified in ASTM D2783.

  "The test operation was performed by rotating one steel ball while applying a load to the three steel balls held stationary in the shape of the cradle. The spheres were coated, the spin speed was 1760 rpm, and the machine and test lubricants were brought from 18.33 ° C. to 35.0 ° C. (65 ° F. to 95 ° F.), followed by a series of 10 second tests. The test was performed with increasing load until fusing occurred.10 tests were performed below the fusing point.When the fusing occurred, 10 loads were not applied, and below the seizure. If the scar was within the 5% compensation line under load, no further testing was necessary. "

  Table 3 shows the results. The reference oil had a load wear index of 29.0. The low phosphorus lubricating oils of the present invention (oils 1-6) were at least equivalent, and oils with additional antiwear / antioxidants (oils 4-6) had at least 13% improved wear.

  The final non-seizure load showed almost the same results. That is, the lubricating oil composition of the present invention has at least the same abrasion performance as the reference oil, and is usually superior to it.

  These results demonstrate the improved wear provided by the lubricating oil composition of the present invention.

Table 3 Bench test results
Oil RBOT TFOUT KHTT FBWT
25PSI reduction Load wear Final non-seizure
Minute index, KGF load, KGF
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1 190 796 6.5 34.4 80
2 223 683 6.5 28.6 63
3 179 388 7.0 28.8 63
4 180 649 6.5 32.9 63
5 177 1026 6.5 35.3 80
6 159 712 7.0 35.3 80
Reference 100 534 8.5 29.0 63
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It is understood that the present invention is not based on the discovery of any of the components disclosed as important novel compositions, or on their individual utility as additives in lubricating oil compositions. Like. Rather, the present invention provides a lubricating oil composition comprising a major amount of a base oil of lubricating viscosity and a minor amount of an ethylene carbonated ashless dispersant, a borated ashless dispersant, and a highly overbased metal-containing detergent. And is based on the discovery of compositions useful for the severe service functions imposed by long emission lives.

Claims (34)

A lubricating oil composition comprising a major amount of a base oil of lubricating viscosity and a minor amount of each of the following components:
a) an ashless dispersant treated with about 3.0 to about 7.0% by weight ethylene carbonate;
b) an ashless dispersant treated with about 2.0 to about 5.0 weight percent borate;
However, the weight ratio a / b is about 0.3 to 0.5.
c) about 1.0 to about 3.0% by weight of a highly overbased metal-containing detergent;
d) from about 0.1 to about 2.0% by weight of a phosphorus-containing compound;
However, the weight% of the total phosphorus in the lubricating oil composition is 0.08% by weight or less based on the total weight of the lubricating oil composition.   The lubricating oil composition of claim 1, further comprising about 0.2 to about 6.0% by weight of a low overbased metal-containing detergent.   The lubricating oil composition of claim 1, further comprising about 0.5 to about 3.0% by weight of a nitrogen-containing ashless antioxidant.   The lubricating oil composition of claim 1, further comprising about 0.3 to about 1.0% by weight of the alkylthiocarbamoyl compound.   The lubricating oil composition of claim 1, further comprising about 0.1 to about 1.5% by weight of a molybdenum-succinimide complex.   The lubricating oil composition according to claim 1, wherein the total amount of phosphorus in the composition is 0.05% by weight or less based on the total weight of the composition.   The lubricating oil composition according to claim 1, wherein the base oil having a lubricating viscosity is selected from the group consisting of a class III base oil, a class IV base oil, a class V base oil, and any mixture thereof.   The lubricating oil composition according to claim 1, wherein the ashless dispersant is selected from the group consisting of alkenyl succinimides, alkenyl succinic anhydrides, alkenyl succinic esters, benzylamine, and mixtures thereof.   The lubricating oil composition according to claim 8, wherein the ashless dispersant is an alkenyl succinimide.   The lubricating oil composition according to claim 9, wherein the alkenyl succinimide is a polyalkylene succinimide.   The lubricating oil composition according to claim 10, wherein the polyalkylene succinimide is polyisobutylene succinimide.   The lubricating oil composition according to claim 1, wherein the metal-containing detergent is a metal phenate or a metal sulfonate.   The lubricating oil composition according to claim 12, wherein the metal-containing detergent is a metal sulfonate.   The lubricating oil composition according to claim 1, wherein the phosphorus-containing compound is selected from the group consisting of metal dithiophosphates, phosphorus esters, amine phosphates, amine phosphinates, sulfur-containing phosphorus esters, phosphorus amides, and phosphonamides.   15. The lubricating oil composition according to claim 14, wherein the phosphorus ester is selected from the group consisting of a phosphate ester, a phosphonate ester, a phosphinate ester, a phosphine oxide, a phosphite ester, a phosphonite ester, a phosphinate ester and a phosphine. object.   The lubricating oil composition according to claim 14, wherein the sulfur-containing phosphorus ester is selected from the group consisting of phosphorus monothionate and phosphodithionate.   The lubricating oil composition according to claim 14, wherein the phosphorus-containing compound is a metal dithiophosphate.   The lubricating oil composition according to claim 17, wherein the metal dithiophosphate is a zinc dialkyldithiophosphate.   The lubricating oil composition according to claim 1, wherein the nitrogen-containing ashless antioxidant is diphenylamine.   The lubricating oil composition according to claim 19, wherein the diphenylamine is an alkylated diphenylamine.   The lubricating oil composition according to claim 1, wherein the alkylthiocarbamoyl compound is an alkylenebis (dialkyldithiocarbamate).   The lubricating oil composition according to claim 21, wherein the alkylenebis (dialkyldithiocarbamate) is methylenebis (dialkyldithiocarbamate).   23. The lubricating oil composition according to claim 22, wherein the methylene bis (dialkyldithiocarbamate) is methylenebis (dibutyldithiocarbamate).   The nitrogen-containing compound used in the molybdenum / nitrogen-containing complex may be a succinimide, a carboxylic amide, a hydrocarbon monoamine, a hydrocarbon polyamine, a Mannich base, a phosphoramide, a thiophosphoramide, a phosphonamide, a dispersant type viscosity index improver and The lubricating oil composition according to claim 1, which is selected from the group consisting of a mixture.   The lubricating oil composition of claim 24, wherein the nitrogen-containing compound is succinimide and the molybdenum / nitrogen-containing complex is molybdenum-succinimide.   The lubricating oil composition according to claim 25, wherein the molybdenum-succinimide is a molybdenum sulfide-succinimide.   The lubricating oil composition according to claim 25, wherein the molybdenum-succinimide is unsulfurized molybdenum-succinimide.   26. The lubricating oil composition of claim 25, wherein the molybdenum-succinimide is used in an amount sufficient to provide about 10 to about 5000 parts per million of molybdenum atoms in the lubricant composition. A method for extending the life of a lubricating oil composition as evidenced by improved wear, extreme pressure, oxidation and sediment control performance, comprising a base oil of a major amount of lubricating viscosity and a minor amount of a lubricating oil comprising: A method comprising operating an internal combustion engine with the composition:
a) from about 3.0 to about 7.0% by weight of an ethylene carbonated ashless dispersant;
b) about 2.0 to about 5.0% by weight of a borated ashless dispersant;
However, the weight ratio a / b is about 0.3 to about 0.5.
c) about 1.0 to about 3.0% by weight of a highly overbased metal-containing detergent;
d) from about 0.1 to about 2.0% by weight of a phosphorus-containing compound;
However, the weight% of the total phosphorus in the lubricating oil composition is 0.08% by weight or less based on the total weight of the lubricating oil composition.   30. The method of claim 29, further comprising about 0.2 to about 0.6% by weight of a low overbased metal-containing detergent.   30. The method of claim 29, further comprising about 0.5 to about 3.0% by weight of a nitrogen-containing ashless antioxidant.   30. The method of claim 29, further comprising about 0.3 to about 1.0% by weight of the alkylthiocarbamoyl compound.   30. The method of claim 29, further comprising about 0.3 to about 1.5% by weight of the molybdenum-succinimide complex. 30. The method according to claim 29, wherein the total amount of phosphorus in the composition is not more than 0.05% by weight based on the total weight of the composition.