Title of Invention	A LUBRICATING OIL FOR INTERNAL COMBUSTION ENGINE
Abstract	A lubricating oil composition used in an internal combustion engine is provided. The internal combusting engine uses a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat, and oil and hydrotreated transesterified natural fat and oil. The lubricating oil composition includes: base oil of lubricating oil; a component (A) containing a boron derivative of an alkyl or alkenyl-substituted succinimide compound having a number average molecular weight of 200 to 5000; and a component (B) containing an alkaline earth metal-based detergent. The component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the composition.

Title of Invention

A LUBRICATING OIL FOR INTERNAL COMBUSTION ENGINE

Abstract

A lubricating oil composition used in an internal combustion engine is provided. The internal combusting engine uses a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat, and oil and hydrotreated transesterified natural fat and oil. The lubricating oil composition includes: base oil of lubricating oil; a component (A) containing a boron derivative of an alkyl or alkenyl-substituted succinimide compound having a number average molecular weight of 200 to 5000; and a component (B) containing an alkaline earth metal-based detergent. The component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the composition.

Full Text	DESCRIPTION LUBRICANT COMPOSITION TECHNICAL FIELD [0001] The present invention relates to a lubricant oil composition to be used in an internal combustion engine that uses a fuel originating from natural fat and oil. BACKGROUND ART [0002] These days, environmental regulations are being increasingly tightened on a global scale, among which fuel efficiency regulations and exhaust emission regulations for automobiles are especially being further tightened. Demands for tightening of the regulations are derived from environmental issues such as global warming and resource conservation due to a concern for depletion of petroleum resources. Meanwhile, plants living on the earth absorb carbon dioxide in the air, water and sunlight to photosynthetically generate carbohydrate and oxygen. What is called, biofuel, which is manufactured from plant-based plant oil, has been gathering remarkable attentions because of its effects on reduction of carbon dioxide (a main cause of global warming) and reduction of atmospheric contaminants emitted from automobiles. In line with an idea of carbon neutral advocating that carbon dioxide generated due to combustion of plant biomass is not counted as a contributor to an increase of the global warming gas, ratio at which the biofuel is mixed in hydrocarbon fuel is expected to be increased in the future (cf. Non-Patent Document 1:). [0003] Non-Patent Document 1: Koji YAMANE, From Biodiesel Deep Fryer to Fuel Tank, (Tokyo-Tosho-Shuppankai, May of 2006) DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION [0004] An important problem in an internal combustion engine, especially in a diesel engine, has been how to reduce environment pollution caused by such emission gas components as particulate matters (PM such as soot) and NOx. An effective solution is to mount such an exhaust purifying device as a diesel particulate filter (DPF) or an exhaust purifying catalyst (oxidization or reduction catalyst) on an automobile. For example, soot generated in the diesel engine adheres to the DPF to be removed by oxidization and combustion. When the DPF is mounted on the diesel engine, post-injection of fuel is generally conducted so as to combust the soot accumulated on the filter. Engine oil is diluted by the fuel due to the post-injection, so that performance of the engine oil is expected to be deteriorated. Particularly, since biofuel can be easily accumulated in the engine oil due to its property and generates polar compounds when degraded and decomposed, the biofuel may adversely affect detergency of engine parts such as a piston. Such a defective phenomenon greatly depends on properties of lubricating oil used in the internal combustion engine. An object of the present invention is to provide a lubricating oil composition that is excellent in lubricity and engine-parts detergency even when biofuel or fuel mixed with the biofuel is employed in an internal combustion engine such as a diesel engine, and that imposes less adverse effects on the environment. MEANS FOR SOLVING THE PROBLEMS [0005] In order to solve the above-mentioned problems, according to an aspect of the present invention, lubricating oil compositions as follows are provided: (1) a lubricating oil composition used in an internal combustion engine, the internal combustion engine using a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat and oil and hydrotreated transesterified natural fat and oil, the lubricating oil composition containing: base oil of lubricating oil; a component (A) containing a boron derivative of a succinimide compound substituted by an alkyl or alkenyl group having a number average molecular weight of 200 to 5000; and a component (B) containing an alkaline earth metal-based detergent, in which the component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the composition. ; [0006] (2) the above-described lubrication oil composition, in which a mass ratio (B/N) of boron (B) and nitrogen (N) contained in the component (A) is 0.5 or more; (3) the above-described lubrication oil composition, in which a phenol-based antioxidant and/or an amine-based antioxidant are contained by 0.3 mass% or more of the total amount of the composition; (4) the above-described lubrication oil composition, in which a sulfur content is 0.5 mass% or less of the total amount of the composition; (5) the above-described lubrication oil composition, in which a phosphorus content is 0.12 mass% or less of the total amount of the composition; and (6) the above-described lubrication oil composition, in which a sulfated ash content is 1.1 mass% or less. [0007] The lubricating oil composition according to the aspect of the present invention exhibits excellent detergency for engine parts such as a piston in the internal combustion engine using what is called biofuel made of natural fat and oil and the like even when the biofuel is mixed into the engine oil. Especially, the lubricating oil is excellent in high-temperature detergency when the engine reaches a high temperature. Even when used in a diesel engine with a DPF, the lubricating oil composition can reduce residual ash content on the DPF, thereby preventing performance of the DPF from being deteriorated. Natural fat and oil used in the present invention is not limited to plant-derived fat and oil but may include animal-derived fat and oil. BEST MODE FOR CARRYING OUT THE INVENTION [0008] An embodiment of the present invention will be described in detail below. A lubricating oil composition according to the present invention is used in an internal combustion engine, the internal combustion engine using a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat and oil and hydrotreated transesterified natural fat and oil. [0009] Although the natural fat and oil may be a variety of animal-derived or plant-derived fat and oil that is generally available in nature, the natural fat and oil is preferably plant oil that contains ester of fatty acid and glycerin as a major ingredient, examples of which are safflower oil, soybean oil, canola oil, palm oil, palm kernel oil, cotton oil, cocoanut oil, rice bran oil, benne oil, castor oil, linseed oil, olive oil, wood oil, camellia oil, earthnut oil, kapok oil, cacao oil, haze wax, sunflower seed oil, corn oil and the like. The hydrotreated natural fat and oil is formed by hydrogenating the above fat and oil under the presence of a suitable hydrogenating catalyst. The hydrogenating catalyst is exemplified by a nickel-based catalyst, a platinum family (Pt, Pd, Rh, Ru) catalyst, a cobalt-based catalyst, a chrome-oxide based catalyst, a copper-based catalyst, an osmium-based catalyst, an iridium-based catalyst, a molybdenum-based catalyst and the like. A combination of two or more of the catalysts may also be preferably used as the hydrogenating catalyst. The transesterified natural fat and oil is ester formed by transesterifying triglyceride contained in the natural fat and oil under the presence of a suitable ester-synthesis catalyst. For instance, by transesterifying lower alcohol and the fat and oil under the presence of the ester-synthesis catalyst, fatty acid ester usable as biofuel is manufactured. The lower alcohol, which is used as an esterifying agent, is exemplified by alcohol having 5 or less carbon atoms such as methanol, ethanol, propanol, butanol, pentanol and the like. In view of reactivity and cost, methanol is preferable. The lower alcohol is generally used in an amount equivalent to the fat and oil or more. The hydrotreated transesterified natural fat and oil is formed by hydrogenating the above transesterified fat and oil under the presence of a suitable hydrogenating catalyst. The natural fat and oil, the hydrotreated natural fat and oil, the transesterified natural fat and oil, and the hydrotreated transesterified natural fat and oil can be preferably used as mixed fuel by adding the above to fuel formed of hydrocarbon such as light oil. [0010] The lubricating base oil used in the lubricating oil composition according to the present invention is not particularly limited but may be suitably selected from any mineral oil and synthetic oil that have been conventionally used as base oil of the lubricating oil for the internal combustion engine. Examples of the mineral oil are mineral oil refined by processing lubricating oil fractions by at least one of solvent-deasphalting, solvent-extracting, hydrocracking, solvent-dewaxing, catalytic-dewaxing and hydrorefining (the lubricating oil fractions are obtained by vacuum-distilling atmospheric residual oil obtained by atmospherically distilling crude oil) and mineral oil manufactured by isomerizing wax and GTL WAX. On the other hand, examples of the synthetic oil are polybutene, polyolefin (α-olefin homopolymer or copolymer such as ethylene-α-olefin copolymer), various esters (such as polyol ester, diacid ester and phosphoric ester), various ethers (such as polyphenylether), polyglycol, alkylbenzene, alkyl naphthalene and the like. Among the above, polyolefin and polyol ester are particularly preferable. In the present invention, one of the above mineral oil may be singularly used or a combination of two or more thereof may be used as the base oil. In addition, one of the above synthetic oil may be singularly used or a combination of two or more thereof may be used. Further, a combination of at least one of the above mineral oil and at least one of the above synthetic oil may be used. [0011] Although viscosity of the base oil subjects to no specific limitation and varies depending on usage of the lubricating oil composition, kinematic viscosity thereof at 100 degrees C is generally preferably 2 to 30 mm /s, more preferably 3 to 15 mm /s, much more preferably 4 to 10 mm /s. When the kinematic viscosity at 100 degrees C is 2 mm /s or more, evaporation loss is small. When the kinematic viscosity at 100 degrees C is 30 mm2/s or less, power loss due to viscosity resistance is restricted, thereby improving fuel efficiency. [0012] As the base oil, oil whose %CA measured by a ring analysis is 3 or less and whose sulfur content is 50 ppm by mass or less can be preferably used. The %CA measured by the ring analysis means a proportion (percentage) of aromatic content calculated by the n-d-M method (a ring analysis). The sulfur content is measured based on Japanese Industrial Standard (hereinafter called, JIS) K 2541. The base oil whose %CA is 3 or less and whose sulfur content is 50 ppm by mass or less exhibits a favorable oxidation stability. Such base oil can restrict an increase of acid number and a generation of sludge, thereby providing a lubricating oil composition that is less corrosive to metal. The sulfur content is more preferably 30 ppm by mass or less. The %CA is more preferably 1 or less, much more preferably 0.5 or less. In addition, viscosity index of the base oil is preferably 70 or more, more preferably 100 or more, much more preferably 120 or more. In the base oil whose viscosity index is 70 or more, a viscosity change due to a temperature change is small. [0013] The component (A) of the lubricating oil composition according to the present invention is a boron derivative of a succinimide compound substituted by an alkyl or alkenyl group having a number average molecular weight of 200 to 5000. Such a boron derivative of the succinimide compound can be obtained by exemplarily reacting (a) a succinic acid substituted by an alkyl or alkenyl group having the number average molecular weight of 200 to 5000 or an anhydride of the succinic acid, (b) polyalkylene polyamine and (c) a boron compound. Materials (a), (b) and (c) and synthetic methods therefor will be described below. As the material (a), the succinic acid substituted by the alkyl or alkenyl group or an anhydride of the succinic acid is used. The number average molecular weight (hereinafter may be abbreviated as molecular weight or Mn) of the alkyl or alkenyl group is typically 200 to 5000, preferably 500 to 2000. When the molecular weight of the alkyl or alkenyl group is less than 200, the eventually-obtained boron derivative of the succinimide compound may not be sufficiently dissolved in the base oil of the lubricating oil. When the molecular weight is more than 5000, the succinimide compound may become so highly viscous as to impair the usability. [0014] As the alkyl or alkenyl group having such a molecular weight, a polymer or a copolymer of monoolefin and diolefin having 2 to 16 carbon atoms or a hydride of the polymer or the copolymer is typically used. Examples of monoolefin are ethylene, propylene, butene, butadiene, decene, dodecene, hexadecene and the like. Among the above-listed monoolefin, butene is particularly preferable in the present invention because of its enhanced high-temperature detergency for the engine parts and its availability. A polybutenyl group (a polymer of the butene) and a hydrogenated polybutenyl group (an alkyl group obtained by hydrogenating the polybutenyl group) are more preferable. [0015] The alkyl or alkenyl substituted succinic acid or an anhydride of the succinic acid as the material (a) may be obtained by reacting a substance such as polybutene having the molecular weight equivalent to that of the alkyl or alkenyl group with a substance such as maleic anhydride by a conventional method. [0016] Although polyalkylene polyamine is used for the material (b), 5 mol% or more of the total material is preferably formed from polyalkylene polyamine having a terminal ring structure. The entirety of the material (b) may be formed from polyalkylene polyamine having a terminal ring structure, or the material may be a mixture of polyalkylene polyamine having a terminal ring structure and polyalkylene polyamine having no terminal ring structure. When polyalkylene polyamine having a terminal ring structure is contained by 5 mol% or more, engine-parts detergency is further improved, which is an object of the present invention. When the content of the polyalkylene polyamine is 10 mol% or more, further 20 mol% or more, the detergency is further improved, especially detergency at a high temperature is enhanced. In the present invention, the upper limit on the content of polyalkylene polyamine having a terminal ring structure is preferably 95 mol% or less, more preferably 90 mol% or less. When the content exceeds 95 mol%, the manufactured boronated succinimide compound may become so highly viscous as to impair manufacturing efficiency of the compound and solubility of the product in the base oil of the lubricating oil may be deteriorated. Accordingly, the content of polyalkylene polyamine having a terminal ring structure is preferably 5 to 95 mol%, more preferably 10 to 90 mol%. The terminal ring structure of polyalkylene polyamine having a terminal ring structure is preferably represented by a formula (1) as follows. [0017] In the formula (1), p and q each represent an integer in a range of 2 to 4. Particularly, a group where both p and q are 2, i.e., piperazinyl group is preferable. A representative example of polyalkylene polyamine having a terminal ring structure is aminoalkyl piperazine having a terminal piperazinyl structure such as aminoethyl piperazine, aminopropyl piperazine, aminobutyl piperazine, amino(diethylenediamino) piperazine, amino(dipropyldiamino) piperazine and the like. Among the above, aminoethyl piperazine is particularly preferable in view of its availability. [0018] On the other hand, polyalkylene polyamine having no terminal ring structure means polyalkylene polyamine having no ring structure or polyalkylene polyamine having a non-terminal ring structure. Representative examples of polyalkylene polyamine having no ring structure are polyethylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine, propylenediamine, dibutylenetriamine, tributylenetriamine and the like. A representative example of polyalkylene polyamine having non-terminal ring structure is di(aminoalkyl) piperazine such as di(aminoethyl) piperazine. [0019] A mixture of polyalkylene polyamine and polyethylene polyamine such as triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine among the above listed polyalkylene polyamine that may have a ring structure is particularly preferable because of its enhanced high-temperature detergency for engine-parts and its availability. [0020] As the material (c), a boron compound is used. Examples of the boron compound are boracic acid, boric anhydride, borate ester, boric oxide and boron halogenide. Among the above, boracic acid is particularly preferable. [0021] The component (A) according to the present invention can be obtained by reacting the materials (a), (b) and (c). Without special limitations, any known methods of reacting can be used. For instance, by reacting the materials by the following manner, the target substance can be obtained. The materials (a) and (b) are initially reacted with each other, then its reaction product is reacted with the material (c). A mixing ratio of the materials (a) to (b) in the reaction of the material (a) and (b) is preferably 0.1-to-10 to 1 (mole ratio), more preferably 0.5-to-2 to 1 (mole ratio). A reaction temperature of the materials (a) and (b) is preferably in a range of approximately 80 to 250 degrees C, more preferably in a range of approximately 100 to 200 degrees C. At the time of reacting, depending on the materials, or in order to adjust the reaction, solvents such as an organic solvent exemplified by hydrocarbon oil may be used as necessary. [0022] Subsequently, the thus-obtained reaction product of the materials (a) and (b) is reacted with the material (c). A mixing ratio of polyalkylene polyamine to the boron compound as the reaction material (c) is typically 1 to 0.05-to-10, preferably 1 to 0.5-to-5 (mole ratio). A reaction temperature therefor is typically approximately 50 to 250 degrees C, preferably 100 to 200 degrees C. At the time of reacting, as in the reaction of the materials (a) and (b), depending on the materials or in order to adjust the reaction, solvents such as an organic solvent exemplified by hydrocarbon oil may be used as necessary. As a product of the above reaction, a boron derivative of a succinimide compound substituted by an alkyl or alkenyl group having a number average molecular weight of 200 to 5000 (the (A) component) is obtained. In the present invention, one of the component (A) may be singularly used or a combination of two or more thereof may be used. [0023] The content of the component (A) in the lubricating oil composition according to the present invention is 0.01 to 0.2 mass% in terms of boron (atoms) of the total amount of the composition, preferably 0.01 to 0.15 mass%, more preferably 0.01 to 0.1 mass%. Since a predetermined amount or more of boron is contained in the component (A), even when biofuel is mixed into the lubricating oil composition, pistons can be favorably cleaned in the high-temperature internal combustion engine. When the content of boron is less than 0.01 mass%, sufficient high-temperature detergency is not obtained. When the content of boron exceeds 0.2 mass%, no further improvement is made on the high-temperature detergency, which is of little practical use. A mass ratio (B/N) of boron (B) and nitrogen (N) contained in the component (A) is preferably 0.5 or more, more preferably 0.6 or more, much more preferably 0.8 or more. When B/N is 0.5 or more, high-temperature detergency for engine parts is greatly enhanced. Although a boronated succinimide-based compound can be obtained by initially reacting the materials (a) and (b) and subsequently reacting the reaction product thereof with the material (c), the reaction order may be changed such that the materials (a) and (c) are initially reacted and the reaction product thereof is subsequently reacted with the material (b). With this reaction order, the target boronated succinimide compound may also be likewise obtained. [0024] The component (B) of the lubricating oil composition according to the present invention is an alkaline earth metal-based detergent. For example, one selected from a group consisting of alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate and a mixture of two or more selected from the group may be preferably used. An example of alkaline earth metal sulfonate is alkaline earth metal salt of alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 300 to 1500 (preferably 400 to 700). The alkaline earth metal salt is exemplified by magnesium salt and/or calcium salt and the like, among which calcium salt is preferably used. An example of alkaline earth metal phenate is alkaline earth metal salt of alkylphenol, alkylphenol sulfide and a Mannich reaction product of alkylphenol. The alkaline earth metal salt is exemplified by magnesium salt and/or calcium salt and the like, among which calcium salt is preferably used. An example of alkaline earth metal salicylate is alkaline earth metal salt of alkyl salicylic acid. The alkaline earth metal salt is exemplified by magnesium salt and/or calcium salt and the like, among which calcium salt is preferably used. An alkyl group forming the alkaline earth metal-based detergent preferably has 4 to 30 carbon atoms. The alkyl group is more preferably a linear or branched alkyl group having 6 to 18 carbon atoms, in which 6 to 18 carbon atoms may be in a linear chain or in a branched chain. The alkyl group may be a primary alkyl group, a secondary alkyl group or a tertiary alkyl group. [0025] In addition, alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate may be neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate obtained by: directly reacting the above-described alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, a Mannich reaction product of alkylphenol, alkyl salicylic acid or the like with alkaline earth metal base exemplified by an oxide or a hydroxide of alkaline earth metal such as magnesium and/or calcium; or converting the above-described substance into alkali metal salt such as sodium salt or potassium salt and subsequently substituting the alkali metal salt with alkaline earth metal salt. Alternatively, alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate may be: basic alkaline earth metal sulfonate, basic alkaline earth metal phenate and basic alkaline earth metal salicylate obtained by heating neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate with excess alkaline earth metal salt or alkaline earth metal base under the presence of water; or overbased alkaline earth metal sulfonate, overbased alkaline earth metal phenate and overbased alkaline earth metal salicylate obtained by reacting neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate with carbonate or borate of alkaline earth metal under the presence of carbon dioxide gas. [0026] In the present invention, the content of the alkaline earth metal-based detergent is 0.35 mass% or less in terms of alkyl earth metal, preferably 0.01 to 0.35 mass%, more preferably 0.1 to 0.35 mass%. When the content of the alkaline earth metal-based detergent is 0.01 mass% or more, the lubricating oil composition exhibits more excellent oxidation stability, base-number retention and high-temperature detergency. On the other hand, when the content of the alkaline earth metal-based detergent exceeds 0.35 mass%, performance of catalyst for purifying exhaust gas may be deteriorated. In addition, when such a detergent is used in a diesel engine with a DPF, an amount of ash content adhering to the DPF may be increased, thereby shorting the life of the DPF. [0027] The lubricating oil composition according to the present invention preferably contains a phenol-based antioxidant and/or an amine-based antioxidant as the antioxidant. Examples of the phenol-based antioxidant are: octadecyl-3 -(3,5 -di-tert-butyl-4-hydroxyphenyl)propionate; 4,4'-methylenebis(2,6-di-t-butylphenol); 4,4'-bis(2,6-di-t-butylphenol); 4,4'-bis(2-methyl-6-t-butylfhenol); 2,2'-methylenebis(4-ethyl-6-t-butylphenol); 2,2' -methylenebis(4-methyl-6-t-butylphenol); 4,4' -butylidenebis(3 -methyl-6-t-butylphenol); 4,4'-isopropylidenebis(2,6-di-t-butylphenol); 2,2'-methylenebis(4-methyl-6-nonylphenol); 2,2' -isobutylidenebis(4,6-dimethylphenol); 2,2'-methylenebis(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-amyl-p-cresol; 2,6-di-t-butyl-4-(N,N'-dimemylaminomethylphenol); 4,4'-thiobis(2-methyl-6-t-butylphenol); 4,4'-thiobis(3-methyl-6-t-butylphenol); 2,2' -thiobis(4-methyl-6-t-butylphenol); bis(3 -methyl-4-hydroxy-5-t-butylbenzyl)sulfide; bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide; n-octyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate; n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate; 2,2'-thio[diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and the like. Among the above, bisphenyl-based antioxidant and ester group-containing phenol-based antioxidant are preferable. [0028] Examples of the amine-based antioxidant are: an antioxidant based on monoalkyldiphenylamine such as monooctyldiphenylamine and monononyldiphenylamine; an antioxidant based on dialkyl diphenylamine such as 4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine, 4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine and 4,4'-dinonyldiphenylamine; an antioxidant based on polyalkyldiphenylamine such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine and tetranonyldiphenylamine; and an antioxidant based on naphthylamine, specifically alkyl-substituted phenyl-a-naphtylamine such as α-naphthylamine, phenyl-a-naphthylamine, butylphenyl-a-naphthylamine, pentylphenyl-α-naphthylamine, hexylphenyl-a-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-a-naphthylamine and nonylphenyl-α-naphthylamine. Among the above, a dialkyl diphenylamine-based antioxidant and a naphthylamine-based antioxidant are preferable. [0029] As another antioxidant, a molybdenum-amine complex-based antioxidant may be used. As the molybdenum-amine complex-based antioxidant, a hexahydric molybdenum compound, an example of which is a reaction product obtained by reacting molybdenum trioxide and/or molybdenum acid with an amine compound, may be used. The reaction product may be, for example, a compound obtained by the manufacturing method disclosed in JP-A-2003-252887. The anime compound to be reacted with the hexahydric molybdenum compound subjects to no particular limitation, and examples thereof are monoamine, diamine, polyamine and alkanolamine. Specific examples of the amine compound are: alkyl amine having an alkyl group of 1 to 30 carbon atoms (the alkyl group may contain a linear chain or a branched chain), exemplified by methylamine, ethylamine, dimethylamine, diethylamine, methylethylamine, methylpropylamine and the like; alkenyl amine having an alkenyl group of 2 to 30 carbon atoms (the alkenyl group may contain a linear chain or a branched chain), exemplified by ethenylamine, propenylamine, butenylamine, octenylamine and oleylamine; alkanol amine having an alkanol group of 1 to 30 carbon atoms (the alkanol group may contain a linear chain or a branched chain), exemplified by methanolamine, ethanolamine, methanolethanolamine and methanolpropanolamine; alkylenediamine having an alkylene group of 1 to 30 carbon atoms, exemplified by methylenediamine, ethylenediamine, propylenediamine and butylenediamine; polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine; a heterocyclic compound obtained by reacting monoamine, diamine and polyamine with a compound having an alkyl or alkenyl group of 8 to 20 carbon atoms or imidazoline, monoamine, diamine and polyamine being exemplified by undecyldiethylamine, undecyldiethanolamine, dodecyldipropanolamine, oleyldiethanolamine, oleylpropylenediamine and stearyltetraethylenepentamine; an alkylene-oxide adduct of the compounds; and a mixture thereof. In addition, sulfur-containing molybdenum complexes of succinimide as disclosed in JP-B-03-22438 and JP-A-2004-2866 may be used. A content of the antioxidant is preferably 0.3 mass% or more of the total amount of the composition, more preferably 0.5 mass% or more. On the other hand, when the content exceeds 2 mass%, the antioxidant may not be dissolved in the base oil of the lubricating oil. Accordingly, the contents of the antioxidant is preferably in a range from 0.3 to 2 mass% of the total amount of the composition. [0030] The lubricating oil composition according to the present invention may be added as necessary with other additives such as a viscosity index improver, a pour point depressant, antiwear agent, an ashless-type friction modifier, a rust inhibitor, a metal deactivator, a surfactant and antifoaming agent as long as effects of the present invention are not hampered. [0031] Examples of the viscosity index improver are polymethacrylate, dispersed polymethacrylate, an olefin-based copolymer (such as an ethylene-propylene copolymer), a dispersed olefin-based copolymer, a styrene-based copolymer (such as a styrene-diene copolymer and a styrene-isoprene copolymer) and the like. In view of blending effects, a content of the viscosity index improver is 0.5 to 15 mass% of the total amount of the composition, preferably 1 to 10 mass%. [0032] An example of the pour point depressant is polymethacrylate having a weight-average molecular weight of 5000 to 50000. Examples of the antiwear agent are: sulfur-containing compounds such as zinc dithiophosphate, zinc dithiocarbamate, zinc phosphate, disulfides, sulfurized olefins, sulfurized fats and oils, sulfurized esters, thiocarbonates, thiocarbamates (such as Mo-DTC) and the like; phosphorus-containing compounds such as phosphite esters, phosphate esters, phosphonate esters and amino salts or metal salts thereof; and a sulfur and phosphorus-containing antiwear agent such as thiophosphite esters, thiophosphate esters (such as Mo-DTP), thiophosphonate esters and amino salts or metal salts thereof. [0033] As the ashless-type friction modifier, any compounds generally used as the ashless-type friction modifier for lubricating oil may be used, examples of which are fatty acid, aliphatic alcohol, aliphatic ether, aliphatic ester, aliphatic amine and aliphatic amide that have at least one alkyl or alkenyl group of 6 to 30 carbon atoms in the molecule. [0034] Examples of the rust inhibitor are petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic ester, multivalent alcohol ester and the like. In view of blending effects, a content of the rust inhibitor is typically 0.01 to 1 mass% of the total amount of the composition, preferably 0.05 to 0.5 mass%. [0035] Examples of the metal deactivator (copper corrosion inhibitor) are benzotriazole-based compounds, tolyltriazole-based compounds, thiadiazole-based compounds and imidazole-based compounds. Among the above, the benzotriazole-based compounds are preferable. By adding the metal deactivator, the engine parts can be prevented from being metallically corroded and degraded due to oxidation. In view of blending effects, a content of the metal deactivator is preferably 0.01 to 0.1 mass% of the total amount of the composition, more preferably 0.03 to 0.05 mass%. [0036] Examples of the surfactant are nonionic surfactants based on polyalkylene glycol such as polyoxyethylenealkylether, polyoxyethylenealkylphenylether and polyoxyethylenealkylnaphthylether. [0037] Examples of the antifoaming agent are silicone oil, fluorosilicone oil, fluoroalkylether and the like. In view of a balance between antifoaming effects and economics, a content of the antifoaming agent is preferably approximately 0.005 to 0.1 mass% of the total amount of the compound. [0038] Sulfur content of the lubricating oil composition according to the present invention is preferably 0.5 mass% or less of the total amount of the composition, more preferably 0.3 mass% or less, much more preferably 0.2 mass% or less. When the sulfur content is 0.5 mass% or less, deterioration of the catalyst performance for purifying exhaust gas can be effectively prevented. Phosphorus content of the lubricating oil composition according to the present invention is preferably 0.12 mass% or less of the total amount of the composition, more preferably 0.1 mass% or less. When the phosphorus content is 0.12 mass% or less, deterioration of the catalyst performance for purifying exhaust gas can be effectively prevented. Sulfated ash content of the lubricating oil composition according to the present invention is preferably 1.1 mass% or less, more preferably 1 mass% or less. When the sulfated ash content is 1.1 mass% or less, deterioration of the catalyst performance for purifying exhaust gas can be effectively prevented. In addition, in a case of a diesel engine, the ash content accumulated on the filter of the DPF can be reduced, thereby preventing the filter blockage due to the ash content and contributing to a long life of the DPF. The sulfated ash content means ash content obtained by adding sulfuric acid carbonized residue caused by combustion of samples for heating so that the residue has a constant mass. The sulfated ash is generally used to know a rough amount of metal-based additives contained in the lubricating oil composition. Specifically, the sulfated ash is measured by a method prescribed in "5. Experiment Method of Sulfated Ash" of JIS K 2272. [0039] Since the lubricating oil composition according to the present invention contains the predetermined amounts of the components (A) and (B), even when used in the internal combustion engine that consumes biofuel, the lubricating oil composition exhibits excellent detergency for the engine parts such as pistons. In addition, when the lubricating oil composition is combusted, exhaust gas produced by the combustion contains less ash content. Accordingly, the lubricating oil composition is favorably applicable especially to a diesel engine with DPF. Examples [0040] Next, the present invention will be further described in detail based on Examples, which by no means limit the present invention. [0041] [Examples 1 to 9 and Comparatives 1 to 3] Lubricating oil compositions containing components shown in Tables 1 and 2 respectively were prepared, which were then subjected to such a hot tube test as follows. The components used for preparing the lubricating oil compositions are as follows. (1) Base Oil of Lubricating Oil: hydrorefined base oil; kinematic viscosity at 40 degrees C of 21 mm2/s; kinematic viscosity at 100 degrees C of 4.5 mm2/s; viscosity index of 127; %CA of 0.1 or less; sulfur content of less than 20 mass ppm; and NOACK evaporation of 13.3 mass%. [0042] (2) Polybutenyl Succinic Monoimide A (Component A): number average molecular weight of the polybutenyl group being 1000; nitrogen content of 1.76 mass%; boron content of 2.0 mass%; and B/N of 1.1. The above polybutenyl succinic monoimide A was manufactured by the following method. 550 g of polybutene (Mn: 980), 1.5 g (0.005 mol) of cetyl bromide and 59 g (0.6 mol) of maleic acid anhydride were put into an autoclave of 1 litter, which were then subjected to nitrogen substitution and reacted with one another at 240 degrees C for five hours. After the temperature was lowered to 215 degrees C, unreacted maleic acid anhydride and unreacted cetyl bromide were distilled away therefrom under a low pressure. After the temperature was further lowered to 140 degrees C, filtration was conducted. An yield of obtained polybutenyl succicic anhydride was 550 g and its saponification number was 86 mg KOH/g. 500 g of obtained polybutenyl succicic anhydride, 17.4 g (0.135 mol) of aminoethyl piperazine (AEP), 10.3 g (0.10 mol) of diethylene triamine (DETA), 14.6 g (0.10 mol) of triethylene tetramine (TETA) and 250 g of mineral oil were put into a separable flask of 1 litter and reacted with one another in nitrogen gas stream at 150 degrees C for two hours. After the temperature was raised to 200 degrees C, unreacted AEP, DETA and TETA and generated water were distilled away therefrom under a low pressure. An yield of obtained polybutenyl succicic imide was 750 g and its base number was 51 mg KOH/g (by a perchloric acid method). 150 g of obtained polybutenyl succicic imide and 20 g of boric acid were put into a separable flask of 500 milliliter and reacted with each other in nitrogen gas stream at 150 degrees C for four hours. After generated water was distilled away therefrom under a low pressure at 150 degrees C, the temperature was lowered to 140 degrees C and filtration was conducted. An yield of generated polybutenyl succinic monoimide A was 165 g and its boron content was 2.0 mass%. Polyalkylene polyamine having a terminal ring structure was approximately 40 mol% of the total polyalkylene polyamine. (3) Polybutenyl Succinic Bisimide B: number average molecular weight of the polybutenyl group being 2000; nitrogen content of 0.99 mass%; and B/N of 0. (4) Polybutenyl Succinic Monoimide C (Component A): number average molecular weight of the polybutenyl group being 1000; nitrogen content of 1.95 mass%; boron content of 0.67 mass%; and B/N of 0.3. Polybutenyl succicic monoimide C was reacted and manufactured by the same method as polybutenyl succicic monoimide A, except that 18 g (0.17 mol) of diethylene triamine (DETA) and 25 g (0.17 mol) of triethylene tetramine (TETA) were used in place of 17.4 g (0.135 mol) of aminoethyl piperazine (AEP), 10.3 g (0.10 mol) of diethylene triamine (DETA) and 14.6 g (0.10 mol) of triethylene tetramine (TETA) and that boric acid was added by 13 g. An yield of generated polybutenyl succinic monoimide C was 161 g. No polyalkylene polyamine having a terminal ring structure was contained therein. [0043] (5) Metal-Based Detergent A (Component B): overbased calcium salicylate; base number of 225 mg KOH/g (perchloric acid method); calcium content of 7.8 mass%; and sulfur content of 0.3 mass%. (6) Metal-Based Detergent B (Component B): overbased calcium phenate; base number of 255 mg KOH/g (perchloric acid method); calcium content of 9.3 mass%; and sulfur content of 3.0 mass%. (7) Metal-Based Detergent C (Component B): calcium sulfonate; base number of 17 mg KOH/g (perchloric acid method); calcium content of 2.4 mass%; and sulfur content of 2.8 mass%. [0044] (8) Phenol-Based Antioxidant: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. (9) Amine-Based Antioxidant: dialkyl diphenylamine; nitrogen content of 4.62 mass%. (10) Viscosity Index Improver: olefin copolymer; mass average molecular weight of 90000; and resin content of 11.1 mass%. (11) Pour Point Depressant: polymethacrylate; and mass average molecular weight of 6000. (12) Zinc Dialkyl Dithio Phosphate: Zn content of 9.0 mass%; phosphorus content of 8.2 mass%; sulfur content of 17.1 mass%; and the alkyl group being a mixture of a secondary butyl group and a secondary hexyl group. (13) Copper Corrosion Inhibitor: l-[N,N-bis(2-ethylhexyl) aminomethyl] methyl benzotriazole. (14) Other Additives: a rust inhibitor, a surfactant and an antifoaming agent. [0045] Measurement of properties of the lubricating oil compositions and the hot tube test were conducted in the following manner. (Calcium Content) Measurement was conducted based on JIS-5S-38-92. (Boron Content) Measurement was conducted based on JIS-5S-38-92. (Nitrogen Content) Measurement was conducted based on JIS K2609. (Phosphorus Content) Measurement was conducted based on JPI-5S-38-92. (Sulfur Content) Measurement was conducted based on JIS K2541. (Sulfated Ash Content) Measurement was conducted based on JIS K2272. [0046] (Hot Tube Test) As the lubricating oil composition to be tested, mixed oil in which biofuel (fuel obtained by transesterifying canola oil with methyl alcohol) was mixed by 5 mass% of each of the lubricating oil compositions (new oil) was used, assuming a mixing ratio of the fuel and the lubricating oil in an internal combustion engine. The measurement was conducted with the test temperature being set at 280 degrees C and other conditions being based on JPI-5S-55-99. For reference, the same test was also conducted using only new oil. In addition, since the hot tube test may be affected by the amount of the viscosity index improver, the mixing amount of the viscosity index improver was made constant among Examples and Comparatives. The smaller an amount of fouling on the glass tube after the test was, the more favorable the detergency is. The properties of the lubricating oil compositions and the results of the hot tube test are shown in Tables 1 and 2. [0047] [Table 1] [0049] [Evaluation Result] As is understood from the results of the hot tube test shown in Tables 1 and 2, Examples 1 to 9, where the lubricating oil composition according to the present invention was used, produced almost as small an amount of fouling as the new oil (i.e., a lubricating oil composition to which no biofuel was added), irrespective of the addition of the biofuel. In contrast, Comparatives 1 and 2, where the component (A) according to the present invention was not contained, produced a much larger amount of fouling than the new oil, thereby exhibiting inferior detergency for the engine. In addition, Comparative 3, where the component (B) according to the present invention was not contained, produced a much larger amount of fouling than the new oil as did Comparatives 1 and 2, thereby exhibiting inferior detergency for the engine. Industrial Applicability [0050] The lubricating oil composition according to the present invention is favorably applicable to an internal combustion engine in which biofuel or fuel mixed with the biofuel is employed. CLAIMS 1. A lubricating oil composition used in an internal combustion engine, the internal combustion engine using a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat and oil and hydrotreated transesterified natural fat and oil, the lubricating oil composition comprising: base oil of lubricating oil; a component (A) containing a boron derivative of a succinimide compound substituted by an alkyl or alkenyl group having a number average molecular weight of 200 to 5000; and a component (B) containing an alkaline earth metal-based detergent, wherein the component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the composition. 2. The lubricant oil composition according to Claim 1, wherein a mass ratio (B/N) of boron (B) and nitrogen (N) contained in the component (A) is 0.5 or more. 3. The lubricant oil composition according to Claim 1 or 2, wherein a phenol-based antioxidant and/or an amine-based antioxidant are contained by 0.3 mass% or more of the total amount of the composition. 4. The lubricant oil composition according to any one of Claims 1 to 3, wherein a sulfur content is 0.5 mass% or less of the total amount of the composition. 5. The lubricant oil composition according to any one of Claims 1 to 4, wherein a phosphorus content is 0.12 mass% or less of the total amount of the composition. 6. The lubricant oil composition according to any one of Claims 1 to 5, wherein a sulfated ash content is 1.1 mass% or less. A lubricating oil composition used in an internal combustion engine is provided. The internal combusting engine uses a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat, and oil and hydrotreated transesterified natural fat and oil. The lubricating oil composition includes: base oil of lubricating oil; a component (A) containing a boron derivative of an alkyl or alkenyl-substituted succinimide compound having a number average molecular weight of 200 to 5000; and a component (B) containing an alkaline earth metal-based detergent. The component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the composition.

Full Text

DESCRIPTION
LUBRICANT COMPOSITION
TECHNICAL FIELD
[0001]
The present invention relates to a lubricant oil composition to be used in an
internal combustion engine that uses a fuel originating from natural fat and oil.
BACKGROUND ART
[0002]
These days, environmental regulations are being increasingly tightened on a
global scale, among which fuel efficiency regulations and exhaust emission regulations for
automobiles are especially being further tightened. Demands for tightening of the
regulations are derived from environmental issues such as global warming and resource
conservation due to a concern for depletion of petroleum resources.
Meanwhile, plants living on the earth absorb carbon dioxide in the air, water and
sunlight to photosynthetically generate carbohydrate and oxygen. What is called, biofuel,
which is manufactured from plant-based plant oil, has been gathering remarkable
attentions because of its effects on reduction of carbon dioxide (a main cause of global
warming) and reduction of atmospheric contaminants emitted from automobiles. In line
with an idea of carbon neutral advocating that carbon dioxide generated due to combustion
of plant biomass is not counted as a contributor to an increase of the global warming gas,
ratio at which the biofuel is mixed in hydrocarbon fuel is expected to be increased in the
future (cf. Non-Patent Document 1:).
[0003]
Non-Patent Document 1: Koji YAMANE, From Biodiesel Deep Fryer to Fuel
Tank, (Tokyo-Tosho-Shuppankai, May of 2006)
DISCLOSURE OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0004]

An important problem in an internal combustion engine, especially in a diesel
engine, has been how to reduce environment pollution caused by such emission gas
components as particulate matters (PM such as soot) and NOx. An effective solution is to
mount such an exhaust purifying device as a diesel particulate filter (DPF) or an exhaust
purifying catalyst (oxidization or reduction catalyst) on an automobile. For example, soot
generated in the diesel engine adheres to the DPF to be removed by oxidization and
combustion.
When the DPF is mounted on the diesel engine, post-injection of fuel is generally
conducted so as to combust the soot accumulated on the filter. Engine oil is diluted by the
fuel due to the post-injection, so that performance of the engine oil is expected to be
deteriorated. Particularly, since biofuel can be easily accumulated in the engine oil due to
its property and generates polar compounds when degraded and decomposed, the biofuel
may adversely affect detergency of engine parts such as a piston. Such a defective
phenomenon greatly depends on properties of lubricating oil used in the internal
combustion engine.
An object of the present invention is to provide a lubricating oil composition that
is excellent in lubricity and engine-parts detergency even when biofuel or fuel mixed with
the biofuel is employed in an internal combustion engine such as a diesel engine, and that
imposes less adverse effects on the environment.
MEANS FOR SOLVING THE PROBLEMS
[0005]
In order to solve the above-mentioned problems, according to an aspect of the
present invention, lubricating oil compositions as follows are provided:
(1) a lubricating oil composition used in an internal combustion engine, the internal
combustion engine using a fuel that contains at least one fat and oil selected from a group
consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat
and oil and hydrotreated transesterified natural fat and oil, the lubricating oil composition
containing: base oil of lubricating oil; a component (A) containing a boron derivative of a
succinimide compound substituted by an alkyl or alkenyl group having a number average

molecular weight of 200 to 5000; and a component (B) containing an alkaline earth
metal-based detergent, in which the component (A) is contained by 0.01 to 0.2 mass% in
terms of boron of a total amount of the composition while the component (B) is contained
by 0.35 mass% or less in terms of the alkaline earth metal of the total amount of the
composition. ;
[0006]
(2) the above-described lubrication oil composition, in which a mass ratio (B/N) of
boron (B) and nitrogen (N) contained in the component (A) is 0.5 or more;
(3) the above-described lubrication oil composition, in which a phenol-based
antioxidant and/or an amine-based antioxidant are contained by 0.3 mass% or more of the
total amount of the composition;
(4) the above-described lubrication oil composition, in which a sulfur content is 0.5
mass% or less of the total amount of the composition;
(5) the above-described lubrication oil composition, in which a phosphorus content is
0.12 mass% or less of the total amount of the composition; and
(6) the above-described lubrication oil composition, in which a sulfated ash content
is 1.1 mass% or less.
[0007]
The lubricating oil composition according to the aspect of the present invention
exhibits excellent detergency for engine parts such as a piston in the internal combustion
engine using what is called biofuel made of natural fat and oil and the like even when the
biofuel is mixed into the engine oil. Especially, the lubricating oil is excellent in
high-temperature detergency when the engine reaches a high temperature. Even when used
in a diesel engine with a DPF, the lubricating oil composition can reduce residual ash
content on the DPF, thereby preventing performance of the DPF from being deteriorated.
Natural fat and oil used in the present invention is not limited to plant-derived fat
and oil but may include animal-derived fat and oil.
BEST MODE FOR CARRYING OUT THE INVENTION

[0008]
An embodiment of the present invention will be described in detail below.
A lubricating oil composition according to the present invention is used in an
internal combustion engine, the internal combustion engine using a fuel that contains at
least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated
natural fat and oil, transesterified natural fat and oil and hydrotreated transesterified
natural fat and oil.
[0009]
Although the natural fat and oil may be a variety of animal-derived or
plant-derived fat and oil that is generally available in nature, the natural fat and oil is
preferably plant oil that contains ester of fatty acid and glycerin as a major ingredient,
examples of which are safflower oil, soybean oil, canola oil, palm oil, palm kernel oil,
cotton oil, cocoanut oil, rice bran oil, benne oil, castor oil, linseed oil, olive oil, wood oil,
camellia oil, earthnut oil, kapok oil, cacao oil, haze wax, sunflower seed oil, corn oil and
the like.
The hydrotreated natural fat and oil is formed by hydrogenating the above fat and
oil under the presence of a suitable hydrogenating catalyst.
The hydrogenating catalyst is exemplified by a nickel-based catalyst, a platinum
family (Pt, Pd, Rh, Ru) catalyst, a cobalt-based catalyst, a chrome-oxide based catalyst, a
copper-based catalyst, an osmium-based catalyst, an iridium-based catalyst, a
molybdenum-based catalyst and the like. A combination of two or more of the catalysts
may also be preferably used as the hydrogenating catalyst.
The transesterified natural fat and oil is ester formed by transesterifying
triglyceride contained in the natural fat and oil under the presence of a suitable
ester-synthesis catalyst. For instance, by transesterifying lower alcohol and the fat and oil
under the presence of the ester-synthesis catalyst, fatty acid ester usable as biofuel is
manufactured. The lower alcohol, which is used as an esterifying agent, is exemplified by
alcohol having 5 or less carbon atoms such as methanol, ethanol, propanol, butanol,
pentanol and the like. In view of reactivity and cost, methanol is preferable. The lower

alcohol is generally used in an amount equivalent to the fat and oil or more.
The hydrotreated transesterified natural fat and oil is formed by hydrogenating
the above transesterified fat and oil under the presence of a suitable hydrogenating
catalyst.
The natural fat and oil, the hydrotreated natural fat and oil, the transesterified
natural fat and oil, and the hydrotreated transesterified natural fat and oil can be preferably
used as mixed fuel by adding the above to fuel formed of hydrocarbon such as light oil.
[0010]
The lubricating base oil used in the lubricating oil composition according to the
present invention is not particularly limited but may be suitably selected from any mineral
oil and synthetic oil that have been conventionally used as base oil of the lubricating oil
for the internal combustion engine.
Examples of the mineral oil are mineral oil refined by processing lubricating oil
fractions by at least one of solvent-deasphalting, solvent-extracting, hydrocracking,
solvent-dewaxing, catalytic-dewaxing and hydrorefining (the lubricating oil fractions are
obtained by vacuum-distilling atmospheric residual oil obtained by atmospherically
distilling crude oil) and mineral oil manufactured by isomerizing wax and GTL WAX.
On the other hand, examples of the synthetic oil are polybutene, polyolefin
(α-olefin homopolymer or copolymer such as ethylene-α-olefin copolymer), various esters
(such as polyol ester, diacid ester and phosphoric ester), various ethers (such as
polyphenylether), polyglycol, alkylbenzene, alkyl naphthalene and the like. Among the
above, polyolefin and polyol ester are particularly preferable.
In the present invention, one of the above mineral oil may be singularly used or a
combination of two or more thereof may be used as the base oil. In addition, one of the
above synthetic oil may be singularly used or a combination of two or more thereof may
be used. Further, a combination of at least one of the above mineral oil and at least one of
the above synthetic oil may be used.
[0011]
Although viscosity of the base oil subjects to no specific limitation and varies

depending on usage of the lubricating oil composition, kinematic viscosity thereof at 100
degrees C is generally preferably 2 to 30 mm /s, more preferably 3 to 15 mm /s, much
more preferably 4 to 10 mm /s. When the kinematic viscosity at 100 degrees C is 2 mm /s
or more, evaporation loss is small. When the kinematic viscosity at 100 degrees C is 30
mm2/s or less, power loss due to viscosity resistance is restricted, thereby improving fuel
efficiency.
[0012]
As the base oil, oil whose %CA measured by a ring analysis is 3 or less and
whose sulfur content is 50 ppm by mass or less can be preferably used. The %CA
measured by the ring analysis means a proportion (percentage) of aromatic content
calculated by the n-d-M method (a ring analysis). The sulfur content is measured based on
Japanese Industrial Standard (hereinafter called, JIS) K 2541.
The base oil whose %CA is 3 or less and whose sulfur content is 50 ppm by mass
or less exhibits a favorable oxidation stability. Such base oil can restrict an increase of acid
number and a generation of sludge, thereby providing a lubricating oil composition that is
less corrosive to metal. The sulfur content is more preferably 30 ppm by mass or less.
The %CA is more preferably 1 or less, much more preferably 0.5 or less.
In addition, viscosity index of the base oil is preferably 70 or more, more
preferably 100 or more, much more preferably 120 or more. In the base oil whose
viscosity index is 70 or more, a viscosity change due to a temperature change is small.
[0013]
The component (A) of the lubricating oil composition according to the present
invention is a boron derivative of a succinimide compound substituted by an alkyl or
alkenyl group having a number average molecular weight of 200 to 5000.
Such a boron derivative of the succinimide compound can be obtained by
exemplarily reacting (a) a succinic acid substituted by an alkyl or alkenyl group having the
number average molecular weight of 200 to 5000 or an anhydride of the succinic acid, (b)
polyalkylene polyamine and (c) a boron compound.
Materials (a), (b) and (c) and synthetic methods therefor will be described below.

As the material (a), the succinic acid substituted by the alkyl or alkenyl group or
an anhydride of the succinic acid is used. The number average molecular weight
(hereinafter may be abbreviated as molecular weight or Mn) of the alkyl or alkenyl group
is typically 200 to 5000, preferably 500 to 2000. When the molecular weight of the alkyl
or alkenyl group is less than 200, the eventually-obtained boron derivative of the
succinimide compound may not be sufficiently dissolved in the base oil of the lubricating
oil. When the molecular weight is more than 5000, the succinimide compound may
become so highly viscous as to impair the usability.
[0014]
As the alkyl or alkenyl group having such a molecular weight, a polymer or a
copolymer of monoolefin and diolefin having 2 to 16 carbon atoms or a hydride of the
polymer or the copolymer is typically used. Examples of monoolefin are ethylene,
propylene, butene, butadiene, decene, dodecene, hexadecene and the like. Among the
above-listed monoolefin, butene is particularly preferable in the present invention because
of its enhanced high-temperature detergency for the engine parts and its availability. A
polybutenyl group (a polymer of the butene) and a hydrogenated polybutenyl group (an
alkyl group obtained by hydrogenating the polybutenyl group) are more preferable.
[0015]
The alkyl or alkenyl substituted succinic acid or an anhydride of the succinic acid
as the material (a) may be obtained by reacting a substance such as polybutene having the
molecular weight equivalent to that of the alkyl or alkenyl group with a substance such as
maleic anhydride by a conventional method.
[0016]
Although polyalkylene polyamine is used for the material (b), 5 mol% or more of
the total material is preferably formed from polyalkylene polyamine having a terminal
ring structure. The entirety of the material (b) may be formed from polyalkylene
polyamine having a terminal ring structure, or the material may be a mixture of
polyalkylene polyamine having a terminal ring structure and polyalkylene polyamine
having no terminal ring structure. When polyalkylene polyamine having a terminal ring

structure is contained by 5 mol% or more, engine-parts detergency is further improved,
which is an object of the present invention. When the content of the polyalkylene
polyamine is 10 mol% or more, further 20 mol% or more, the detergency is further
improved, especially detergency at a high temperature is enhanced.
In the present invention, the upper limit on the content of polyalkylene polyamine
having a terminal ring structure is preferably 95 mol% or less, more preferably 90 mol%
or less. When the content exceeds 95 mol%, the manufactured boronated succinimide
compound may become so highly viscous as to impair manufacturing efficiency of the
compound and solubility of the product in the base oil of the lubricating oil may be
deteriorated. Accordingly, the content of polyalkylene polyamine having a terminal ring
structure is preferably 5 to 95 mol%, more preferably 10 to 90 mol%.
The terminal ring structure of polyalkylene polyamine having a terminal ring
structure is preferably represented by a formula (1) as follows.
[0017]

In the formula (1), p and q each represent an integer in a range of 2 to 4.
Particularly, a group where both p and q are 2, i.e., piperazinyl group is preferable. A
representative example of polyalkylene polyamine having a terminal ring structure is
aminoalkyl piperazine having a terminal piperazinyl structure such as aminoethyl
piperazine, aminopropyl piperazine, aminobutyl piperazine, amino(diethylenediamino)
piperazine, amino(dipropyldiamino) piperazine and the like. Among the above,
aminoethyl piperazine is particularly preferable in view of its availability.
[0018]
On the other hand, polyalkylene polyamine having no terminal ring structure
means polyalkylene polyamine having no ring structure or polyalkylene polyamine having
a non-terminal ring structure. Representative examples of polyalkylene polyamine having

no ring structure are polyethylene polyamines such as ethylenediamine,
diethylenetriamine, triethylenetetramine, tetraethylenepentamine and
pentaethylenehexamine, propylenediamine, dibutylenetriamine, tributylenetriamine and
the like. A representative example of polyalkylene polyamine having non-terminal ring
structure is di(aminoalkyl) piperazine such as di(aminoethyl) piperazine.
[0019]
A mixture of polyalkylene polyamine and polyethylene polyamine such as
triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine among the above
listed polyalkylene polyamine that may have a ring structure is particularly preferable
because of its enhanced high-temperature detergency for engine-parts and its availability.
[0020]
As the material (c), a boron compound is used. Examples of the boron compound
are boracic acid, boric anhydride, borate ester, boric oxide and boron halogenide. Among
the above, boracic acid is particularly preferable.
[0021]
The component (A) according to the present invention can be obtained by
reacting the materials (a), (b) and (c). Without special limitations, any known methods of
reacting can be used. For instance, by reacting the materials by the following manner, the
target substance can be obtained. The materials (a) and (b) are initially reacted with each
other, then its reaction product is reacted with the material (c). A mixing ratio of the
materials (a) to (b) in the reaction of the material (a) and (b) is preferably 0.1-to-10 to 1
(mole ratio), more preferably 0.5-to-2 to 1 (mole ratio). A reaction temperature of the
materials (a) and (b) is preferably in a range of approximately 80 to 250 degrees C, more
preferably in a range of approximately 100 to 200 degrees C. At the time of reacting,
depending on the materials, or in order to adjust the reaction, solvents such as an organic
solvent exemplified by hydrocarbon oil may be used as necessary.
[0022]
Subsequently, the thus-obtained reaction product of the materials (a) and (b) is
reacted with the material (c). A mixing ratio of polyalkylene polyamine to the boron

compound as the reaction material (c) is typically 1 to 0.05-to-10, preferably 1 to 0.5-to-5
(mole ratio). A reaction temperature therefor is typically approximately 50 to 250 degrees
C, preferably 100 to 200 degrees C. At the time of reacting, as in the reaction of the
materials (a) and (b), depending on the materials or in order to adjust the reaction, solvents
such as an organic solvent exemplified by hydrocarbon oil may be used as necessary.
As a product of the above reaction, a boron derivative of a succinimide
compound substituted by an alkyl or alkenyl group having a number average molecular
weight of 200 to 5000 (the (A) component) is obtained. In the present invention, one of
the component (A) may be singularly used or a combination of two or more thereof may
be used.
[0023]
The content of the component (A) in the lubricating oil composition according to
the present invention is 0.01 to 0.2 mass% in terms of boron (atoms) of the total amount of
the composition, preferably 0.01 to 0.15 mass%, more preferably 0.01 to 0.1 mass%.
Since a predetermined amount or more of boron is contained in the component (A), even
when biofuel is mixed into the lubricating oil composition, pistons can be favorably
cleaned in the high-temperature internal combustion engine. When the content of boron is
less than 0.01 mass%, sufficient high-temperature detergency is not obtained. When the
content of boron exceeds 0.2 mass%, no further improvement is made on the
high-temperature detergency, which is of little practical use.
A mass ratio (B/N) of boron (B) and nitrogen (N) contained in the component (A)
is preferably 0.5 or more, more preferably 0.6 or more, much more preferably 0.8 or more.
When B/N is 0.5 or more, high-temperature detergency for engine parts is greatly
enhanced.
Although a boronated succinimide-based compound can be obtained by initially
reacting the materials (a) and (b) and subsequently reacting the reaction product thereof
with the material (c), the reaction order may be changed such that the materials (a) and (c)
are initially reacted and the reaction product thereof is subsequently reacted with the
material (b). With this reaction order, the target boronated succinimide compound may

also be likewise obtained.
[0024]
The component (B) of the lubricating oil composition according to the present
invention is an alkaline earth metal-based detergent. For example, one selected from a
group consisting of alkaline earth metal sulfonate, alkaline earth metal phenate and
alkaline earth metal salicylate and a mixture of two or more selected from the group may
be preferably used.
An example of alkaline earth metal sulfonate is alkaline earth metal salt of alkyl
aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a
molecular weight of 300 to 1500 (preferably 400 to 700). The alkaline earth metal salt is
exemplified by magnesium salt and/or calcium salt and the like, among which calcium salt
is preferably used.
An example of alkaline earth metal phenate is alkaline earth metal salt of
alkylphenol, alkylphenol sulfide and a Mannich reaction product of alkylphenol. The
alkaline earth metal salt is exemplified by magnesium salt and/or calcium salt and the like,
among which calcium salt is preferably used.
An example of alkaline earth metal salicylate is alkaline earth metal salt of alkyl
salicylic acid. The alkaline earth metal salt is exemplified by magnesium salt and/or
calcium salt and the like, among which calcium salt is preferably used. An alkyl group
forming the alkaline earth metal-based detergent preferably has 4 to 30 carbon atoms. The
alkyl group is more preferably a linear or branched alkyl group having 6 to 18 carbon
atoms, in which 6 to 18 carbon atoms may be in a linear chain or in a branched chain. The
alkyl group may be a primary alkyl group, a secondary alkyl group or a tertiary alkyl
group.
[0025]
In addition, alkaline earth metal sulfonate, alkaline earth metal phenate and
alkaline earth metal salicylate may be neutral alkaline earth metal sulfonate, neutral
alkaline earth metal phenate and neutral alkaline earth metal salicylate obtained by:
directly reacting the above-described alkyl aromatic sulfonic acid, alkylphenol,

alkylphenol sulfide, a Mannich reaction product of alkylphenol, alkyl salicylic acid or the
like with alkaline earth metal base exemplified by an oxide or a hydroxide of alkaline
earth metal such as magnesium and/or calcium; or converting the above-described
substance into alkali metal salt such as sodium salt or potassium salt and subsequently
substituting the alkali metal salt with alkaline earth metal salt. Alternatively, alkaline earth
metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate may be:
basic alkaline earth metal sulfonate, basic alkaline earth metal phenate and basic alkaline
earth metal salicylate obtained by heating neutral alkaline earth metal sulfonate, neutral
alkaline earth metal phenate and neutral alkaline earth metal salicylate with excess
alkaline earth metal salt or alkaline earth metal base under the presence of water; or
overbased alkaline earth metal sulfonate, overbased alkaline earth metal phenate and
overbased alkaline earth metal salicylate obtained by reacting neutral alkaline earth metal
sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate
with carbonate or borate of alkaline earth metal under the presence of carbon dioxide gas.
[0026]
In the present invention, the content of the alkaline earth metal-based detergent is
0.35 mass% or less in terms of alkyl earth metal, preferably 0.01 to 0.35 mass%, more
preferably 0.1 to 0.35 mass%. When the content of the alkaline earth metal-based
detergent is 0.01 mass% or more, the lubricating oil composition exhibits more excellent
oxidation stability, base-number retention and high-temperature detergency. On the other
hand, when the content of the alkaline earth metal-based detergent exceeds 0.35 mass%,
performance of catalyst for purifying exhaust gas may be deteriorated. In addition, when
such a detergent is used in a diesel engine with a DPF, an amount of ash content adhering
to the DPF may be increased, thereby shorting the life of the DPF.
[0027]
The lubricating oil composition according to the present invention preferably
contains a phenol-based antioxidant and/or an amine-based antioxidant as the antioxidant.
Examples of the phenol-based antioxidant are:
octadecyl-3 -(3,5 -di-tert-butyl-4-hydroxyphenyl)propionate;

4,4'-methylenebis(2,6-di-t-butylphenol); 4,4'-bis(2,6-di-t-butylphenol);
4,4'-bis(2-methyl-6-t-butylfhenol); 2,2'-methylenebis(4-ethyl-6-t-butylphenol);
2,2' -methylenebis(4-methyl-6-t-butylphenol);
4,4' -butylidenebis(3 -methyl-6-t-butylphenol);
4,4'-isopropylidenebis(2,6-di-t-butylphenol); 2,2'-methylenebis(4-methyl-6-nonylphenol);
2,2' -isobutylidenebis(4,6-dimethylphenol);
2,2'-methylenebis(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-amyl-p-cresol;
2,6-di-t-butyl-4-(N,N'-dimemylaminomethylphenol);
4,4'-thiobis(2-methyl-6-t-butylphenol); 4,4'-thiobis(3-methyl-6-t-butylphenol);
2,2' -thiobis(4-methyl-6-t-butylphenol); bis(3 -methyl-4-hydroxy-5-t-butylbenzyl)sulfide;
bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide;
n-octyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate;
n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate;
2,2'-thio[diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and the like. Among
the above, bisphenyl-based antioxidant and ester group-containing phenol-based
antioxidant are preferable.
[0028]
Examples of the amine-based antioxidant are: an antioxidant based on
monoalkyldiphenylamine such as monooctyldiphenylamine and
monononyldiphenylamine; an antioxidant based on dialkyl diphenylamine such as
4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine, 4,4'-dihexyldiphenylamine,
4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine and 4,4'-dinonyldiphenylamine;
an antioxidant based on polyalkyldiphenylamine such as tetrabutyldiphenylamine,
tetrahexyldiphenylamine, tetraoctyldiphenylamine and tetranonyldiphenylamine; and an
antioxidant based on naphthylamine, specifically alkyl-substituted phenyl-a-naphtylamine
such as α-naphthylamine, phenyl-a-naphthylamine, butylphenyl-a-naphthylamine,
pentylphenyl-α-naphthylamine, hexylphenyl-a-naphthylamine,
heptylphenyl-α-naphthylamine, octylphenyl-a-naphthylamine and

nonylphenyl-α-naphthylamine. Among the above, a dialkyl diphenylamine-based
antioxidant and a naphthylamine-based antioxidant are preferable.
[0029]
As another antioxidant, a molybdenum-amine complex-based antioxidant may be
used. As the molybdenum-amine complex-based antioxidant, a hexahydric molybdenum
compound, an example of which is a reaction product obtained by reacting molybdenum
trioxide and/or molybdenum acid with an amine compound, may be used. The reaction
product may be, for example, a compound obtained by the manufacturing method
disclosed in JP-A-2003-252887. The anime compound to be reacted with the hexahydric
molybdenum compound subjects to no particular limitation, and examples thereof are
monoamine, diamine, polyamine and alkanolamine. Specific examples of the amine
compound are: alkyl amine having an alkyl group of 1 to 30 carbon atoms (the alkyl group
may contain a linear chain or a branched chain), exemplified by methylamine, ethylamine,
dimethylamine, diethylamine, methylethylamine, methylpropylamine and the like; alkenyl
amine having an alkenyl group of 2 to 30 carbon atoms (the alkenyl group may contain a
linear chain or a branched chain), exemplified by ethenylamine, propenylamine,
butenylamine, octenylamine and oleylamine; alkanol amine having an alkanol group of 1
to 30 carbon atoms (the alkanol group may contain a linear chain or a branched chain),
exemplified by methanolamine, ethanolamine, methanolethanolamine and
methanolpropanolamine; alkylenediamine having an alkylene group of 1 to 30 carbon
atoms, exemplified by methylenediamine, ethylenediamine, propylenediamine and
butylenediamine; polyamine such as diethylenetriamine, triethylenetetramine,
tetraethylenepentamine and pentaethylenehexamine; a heterocyclic compound obtained by
reacting monoamine, diamine and polyamine with a compound having an alkyl or alkenyl
group of 8 to 20 carbon atoms or imidazoline, monoamine, diamine and polyamine being
exemplified by undecyldiethylamine, undecyldiethanolamine, dodecyldipropanolamine,
oleyldiethanolamine, oleylpropylenediamine and stearyltetraethylenepentamine; an
alkylene-oxide adduct of the compounds; and a mixture thereof. In addition,
sulfur-containing molybdenum complexes of succinimide as disclosed in JP-B-03-22438

and JP-A-2004-2866 may be used.
A content of the antioxidant is preferably 0.3 mass% or more of the total amount
of the composition, more preferably 0.5 mass% or more. On the other hand, when the
content exceeds 2 mass%, the antioxidant may not be dissolved in the base oil of the
lubricating oil. Accordingly, the contents of the antioxidant is preferably in a range from
0.3 to 2 mass% of the total amount of the composition.
[0030]
The lubricating oil composition according to the present invention may be added
as necessary with other additives such as a viscosity index improver, a pour point
depressant, antiwear agent, an ashless-type friction modifier, a rust inhibitor, a metal
deactivator, a surfactant and antifoaming agent as long as effects of the present invention
are not hampered.
[0031]
Examples of the viscosity index improver are polymethacrylate, dispersed
polymethacrylate, an olefin-based copolymer (such as an ethylene-propylene copolymer),
a dispersed olefin-based copolymer, a styrene-based copolymer (such as a styrene-diene
copolymer and a styrene-isoprene copolymer) and the like. In view of blending effects, a
content of the viscosity index improver is 0.5 to 15 mass% of the total amount of the
composition, preferably 1 to 10 mass%.
[0032]
An example of the pour point depressant is polymethacrylate having a
weight-average molecular weight of 5000 to 50000.
Examples of the antiwear agent are: sulfur-containing compounds such as zinc
dithiophosphate, zinc dithiocarbamate, zinc phosphate, disulfides, sulfurized olefins,
sulfurized fats and oils, sulfurized esters, thiocarbonates, thiocarbamates (such as
Mo-DTC) and the like; phosphorus-containing compounds such as phosphite esters,
phosphate esters, phosphonate esters and amino salts or metal salts thereof; and a sulfur
and phosphorus-containing antiwear agent such as thiophosphite esters, thiophosphate
esters (such as Mo-DTP), thiophosphonate esters and amino salts or metal salts thereof.

[0033]
As the ashless-type friction modifier, any compounds generally used as the
ashless-type friction modifier for lubricating oil may be used, examples of which are fatty
acid, aliphatic alcohol, aliphatic ether, aliphatic ester, aliphatic amine and aliphatic amide
that have at least one alkyl or alkenyl group of 6 to 30 carbon atoms in the molecule.
[0034]
Examples of the rust inhibitor are petroleum sulfonate, alkylbenzene sulfonate,
dinonylnaphthalene sulfonate, alkenyl succinic ester, multivalent alcohol ester and the like.
In view of blending effects, a content of the rust inhibitor is typically 0.01 to 1 mass% of
the total amount of the composition, preferably 0.05 to 0.5 mass%.
[0035]
Examples of the metal deactivator (copper corrosion inhibitor) are
benzotriazole-based compounds, tolyltriazole-based compounds, thiadiazole-based
compounds and imidazole-based compounds. Among the above, the benzotriazole-based
compounds are preferable. By adding the metal deactivator, the engine parts can be
prevented from being metallically corroded and degraded due to oxidation. In view of
blending effects, a content of the metal deactivator is preferably 0.01 to 0.1 mass% of the
total amount of the composition, more preferably 0.03 to 0.05 mass%.
[0036]
Examples of the surfactant are nonionic surfactants based on polyalkylene glycol
such as polyoxyethylenealkylether, polyoxyethylenealkylphenylether and
polyoxyethylenealkylnaphthylether.
[0037]
Examples of the antifoaming agent are silicone oil, fluorosilicone oil,
fluoroalkylether and the like. In view of a balance between antifoaming effects and
economics, a content of the antifoaming agent is preferably approximately 0.005 to 0.1
mass% of the total amount of the compound.
[0038]
Sulfur content of the lubricating oil composition according to the present

invention is preferably 0.5 mass% or less of the total amount of the composition, more
preferably 0.3 mass% or less, much more preferably 0.2 mass% or less. When the sulfur
content is 0.5 mass% or less, deterioration of the catalyst performance for purifying
exhaust gas can be effectively prevented.
Phosphorus content of the lubricating oil composition according to the present
invention is preferably 0.12 mass% or less of the total amount of the composition, more
preferably 0.1 mass% or less. When the phosphorus content is 0.12 mass% or less,
deterioration of the catalyst performance for purifying exhaust gas can be effectively
prevented.
Sulfated ash content of the lubricating oil composition according to the present
invention is preferably 1.1 mass% or less, more preferably 1 mass% or less. When the
sulfated ash content is 1.1 mass% or less, deterioration of the catalyst performance for
purifying exhaust gas can be effectively prevented. In addition, in a case of a diesel engine,
the ash content accumulated on the filter of the DPF can be reduced, thereby preventing
the filter blockage due to the ash content and contributing to a long life of the DPF. The
sulfated ash content means ash content obtained by adding sulfuric acid carbonized
residue caused by combustion of samples for heating so that the residue has a constant
mass. The sulfated ash is generally used to know a rough amount of metal-based additives
contained in the lubricating oil composition. Specifically, the sulfated ash is measured by a
method prescribed in "5. Experiment Method of Sulfated Ash" of JIS K 2272.
[0039]
Since the lubricating oil composition according to the present invention contains
the predetermined amounts of the components (A) and (B), even when used in the internal
combustion engine that consumes biofuel, the lubricating oil composition exhibits
excellent detergency for the engine parts such as pistons. In addition, when the lubricating
oil composition is combusted, exhaust gas produced by the combustion contains less ash
content. Accordingly, the lubricating oil composition is favorably applicable especially to
a diesel engine with DPF.
Examples

[0040]
Next, the present invention will be further described in detail based on Examples,
which by no means limit the present invention.
[0041]
[Examples 1 to 9 and Comparatives 1 to 3]
Lubricating oil compositions containing components shown in Tables 1 and 2
respectively were prepared, which were then subjected to such a hot tube test as follows.
The components used for preparing the lubricating oil compositions are as follows.
(1) Base Oil of Lubricating Oil: hydrorefined base oil; kinematic viscosity at 40
degrees C of 21 mm2/s; kinematic viscosity at 100 degrees C of 4.5 mm2/s; viscosity index
of 127; %CA of 0.1 or less; sulfur content of less than 20 mass ppm; and NOACK
evaporation of 13.3 mass%.
[0042]
(2) Polybutenyl Succinic Monoimide A (Component A): number average molecular
weight of the polybutenyl group being 1000; nitrogen content of 1.76 mass%; boron
content of 2.0 mass%; and B/N of 1.1.
The above polybutenyl succinic monoimide A was manufactured by the following
method. 550 g of polybutene (Mn: 980), 1.5 g (0.005 mol) of cetyl bromide and 59 g (0.6
mol) of maleic acid anhydride were put into an autoclave of 1 litter, which were then
subjected to nitrogen substitution and reacted with one another at 240 degrees C for five
hours. After the temperature was lowered to 215 degrees C, unreacted maleic acid
anhydride and unreacted cetyl bromide were distilled away therefrom under a low pressure.
After the temperature was further lowered to 140 degrees C, filtration was conducted. An
yield of obtained polybutenyl succicic anhydride was 550 g and its saponification number
was 86 mg KOH/g. 500 g of obtained polybutenyl succicic anhydride, 17.4 g (0.135 mol)
of aminoethyl piperazine (AEP), 10.3 g (0.10 mol) of diethylene triamine (DETA), 14.6 g
(0.10 mol) of triethylene tetramine (TETA) and 250 g of mineral oil were put into a
separable flask of 1 litter and reacted with one another in nitrogen gas stream at 150
degrees C for two hours. After the temperature was raised to 200 degrees C, unreacted

AEP, DETA and TETA and generated water were distilled away therefrom under a low
pressure. An yield of obtained polybutenyl succicic imide was 750 g and its base number
was 51 mg KOH/g (by a perchloric acid method). 150 g of obtained polybutenyl succicic
imide and 20 g of boric acid were put into a separable flask of 500 milliliter and reacted
with each other in nitrogen gas stream at 150 degrees C for four hours. After generated
water was distilled away therefrom under a low pressure at 150 degrees C, the temperature
was lowered to 140 degrees C and filtration was conducted. An yield of generated
polybutenyl succinic monoimide A was 165 g and its boron content was 2.0 mass%.
Polyalkylene polyamine having a terminal ring structure was approximately 40 mol% of
the total polyalkylene polyamine.
(3) Polybutenyl Succinic Bisimide B: number average molecular weight of the
polybutenyl group being 2000; nitrogen content of 0.99 mass%; and B/N of 0.
(4) Polybutenyl Succinic Monoimide C (Component A): number average molecular
weight of the polybutenyl group being 1000; nitrogen content of 1.95 mass%; boron
content of 0.67 mass%; and B/N of 0.3.
Polybutenyl succicic monoimide C was reacted and manufactured by the same
method as polybutenyl succicic monoimide A, except that 18 g (0.17 mol) of diethylene
triamine (DETA) and 25 g (0.17 mol) of triethylene tetramine (TETA) were used in place
of 17.4 g (0.135 mol) of aminoethyl piperazine (AEP), 10.3 g (0.10 mol) of diethylene
triamine (DETA) and 14.6 g (0.10 mol) of triethylene tetramine (TETA) and that boric
acid was added by 13 g. An yield of generated polybutenyl succinic monoimide C was 161
g. No polyalkylene polyamine having a terminal ring structure was contained therein.
[0043]
(5) Metal-Based Detergent A (Component B): overbased calcium salicylate; base
number of 225 mg KOH/g (perchloric acid method); calcium content of 7.8 mass%; and
sulfur content of 0.3 mass%.
(6) Metal-Based Detergent B (Component B): overbased calcium phenate; base
number of 255 mg KOH/g (perchloric acid method); calcium content of 9.3 mass%; and
sulfur content of 3.0 mass%.

(7) Metal-Based Detergent C (Component B): calcium sulfonate; base number of 17
mg KOH/g (perchloric acid method); calcium content of 2.4 mass%; and sulfur content of
2.8 mass%.
[0044]
(8) Phenol-Based Antioxidant:
octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.
(9) Amine-Based Antioxidant: dialkyl diphenylamine; nitrogen content of 4.62
mass%.
(10) Viscosity Index Improver: olefin copolymer; mass average molecular weight of
90000; and resin content of 11.1 mass%.
(11) Pour Point Depressant: polymethacrylate; and mass average molecular weight
of 6000.
(12) Zinc Dialkyl Dithio Phosphate: Zn content of 9.0 mass%; phosphorus content
of 8.2 mass%; sulfur content of 17.1 mass%; and the alkyl group being a mixture of a
secondary butyl group and a secondary hexyl group.
(13) Copper Corrosion Inhibitor: l-[N,N-bis(2-ethylhexyl) aminomethyl] methyl
benzotriazole.
(14) Other Additives: a rust inhibitor, a surfactant and an antifoaming agent.
[0045]
Measurement of properties of the lubricating oil compositions and the hot tube
test were conducted in the following manner.
(Calcium Content)
Measurement was conducted based on JIS-5S-38-92.
(Boron Content)
Measurement was conducted based on JIS-5S-38-92.
(Nitrogen Content)
Measurement was conducted based on JIS K2609.
(Phosphorus Content)
Measurement was conducted based on JPI-5S-38-92.

(Sulfur Content)
Measurement was conducted based on JIS K2541.
(Sulfated Ash Content)
Measurement was conducted based on JIS K2272.
[0046]
(Hot Tube Test)
As the lubricating oil composition to be tested, mixed oil in which biofuel (fuel
obtained by transesterifying canola oil with methyl alcohol) was mixed by 5 mass% of
each of the lubricating oil compositions (new oil) was used, assuming a mixing ratio of the
fuel and the lubricating oil in an internal combustion engine. The measurement was
conducted with the test temperature being set at 280 degrees C and other conditions being
based on JPI-5S-55-99. For reference, the same test was also conducted using only new oil.
In addition, since the hot tube test may be affected by the amount of the viscosity index
improver, the mixing amount of the viscosity index improver was made constant among
Examples and Comparatives. The smaller an amount of fouling on the glass tube after the
test was, the more favorable the detergency is.
The properties of the lubricating oil compositions and the results of the hot tube
test are shown in Tables 1 and 2.
[0047]
[Table 1]

[0049]
[Evaluation Result]
As is understood from the results of the hot tube test shown in Tables 1 and 2,
Examples 1 to 9, where the lubricating oil composition according to the present invention
was used, produced almost as small an amount of fouling as the new oil (i.e., a lubricating
oil composition to which no biofuel was added), irrespective of the addition of the biofuel.
In contrast, Comparatives 1 and 2, where the component (A) according to the present
invention was not contained, produced a much larger amount of fouling than the new oil,
thereby exhibiting inferior detergency for the engine. In addition, Comparative 3, where
the component (B) according to the present invention was not contained, produced a much
larger amount of fouling than the new oil as did Comparatives 1 and 2, thereby exhibiting
inferior detergency for the engine.
Industrial Applicability
[0050]
The lubricating oil composition according to the present invention is favorably
applicable to an internal combustion engine in which biofuel or fuel mixed with the
biofuel is employed.

CLAIMS
1. A lubricating oil composition used in an internal combustion engine, the internal
combustion engine using a fuel that contains at least one fat and oil selected from a group
consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat
and oil and hydrotreated transesterified natural fat and oil, the lubricating oil composition
comprising:
base oil of lubricating oil;
a component (A) containing a boron derivative of a succinimide compound
substituted by an alkyl or alkenyl group having a number average molecular weight of 200
to 5000; and
a component (B) containing an alkaline earth metal-based detergent, wherein
the component (A) is contained by 0.01 to 0.2 mass% in terms of boron of a total
amount of the composition while the component (B) is contained by 0.35 mass% or less in
terms of the alkaline earth metal of the total amount of the composition.
2. The lubricant oil composition according to Claim 1, wherein a mass ratio (B/N)
of boron (B) and nitrogen (N) contained in the component (A) is 0.5 or more.
3. The lubricant oil composition according to Claim 1 or 2, wherein a phenol-based
antioxidant and/or an amine-based antioxidant are contained by 0.3 mass% or more of the
total amount of the composition.
4. The lubricant oil composition according to any one of Claims 1 to 3, wherein a
sulfur content is 0.5 mass% or less of the total amount of the composition.
5. The lubricant oil composition according to any one of Claims 1 to 4, wherein a
phosphorus content is 0.12 mass% or less of the total amount of the composition.
6. The lubricant oil composition according to any one of Claims 1 to 5, wherein a

sulfated ash content is 1.1 mass% or less.

A lubricating oil composition used in an internal combustion engine is provided.
The internal combusting engine uses a fuel that contains at least one fat and oil selected
from a group consisting of natural fat and oil, hydrotreated natural fat and oil,
transesterified natural fat, and oil and hydrotreated transesterified natural fat and oil. The
lubricating oil composition includes: base oil of lubricating oil; a component (A)
containing a boron derivative of an alkyl or alkenyl-substituted succinimide compound
having a number average molecular weight of 200 to 5000; and a component (B)
containing an alkaline earth metal-based detergent. The component (A) is contained by
0.01 to 0.2 mass% in terms of boron of a total amount of the composition while the
component (B) is contained by 0.35 mass% or less in terms of the alkaline earth metal of
the total amount of the composition.

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Patent Number

270244

Indian Patent Application Number

3294/KOLNP/2009

PG Journal Number

49/2015

Publication Date

04-Dec-2015

Grant Date

04-Dec-2015

Date of Filing

16-Sep-2009

Name of Patentee

IDEMITSU KOSAN CO., LTD.

Applicant Address

1-1, MARUNOUCHI 3-CHOME, CHIYODA-KU, TOKYO 1008321 JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	KAMANO, HIDEKI	24-4, ANESAKIKAIGAN, ICHIHARA-SHI, CHIBA 2990107 JAPAN
2	TESHIMA, KAZUHIRO	24-4, ANESAKIKAIGAN, ICHIHARA-SHI, CHIBA 2990107 JAPAN

PCT International Classification Number

C10M169/04; C10M143/00; C10N20/02

PCT International Application Number

PCT/JP2008/055436

PCT International Filing date

2008-03-24

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2007-084307	2007-03-28	Japan