JP2008144019A - Lubricating oil composition for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide lubricating oil composition for an internal combustion engine for a hybrid automobile, excellent in hydrolysis stability, also excellent in maintaining performance of a base value even under a condition of easily mingling and accumulating water content and having a good high temperature cleaning property. <P>SOLUTION: This lubricating oil composition for the internal combustion engine comprises (B1) 0.005 to 0.5 mass% salicylate-based cleaning agent based on the amount of a metal, (C) 0.005 to 0.4 mass% succinimide-based ashless dispersing agent consisting only of (C2) succinimide-based ashless dispersing agent without containing boron, and (D) 0.005 to 0.2 mass% metal salt of phosphorus-containing acid based on the amount of the phosphorus in (A) the base oil of lubricating oil, based on the total amount of the composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricating oil composition for an internal combustion engine of a hybrid vehicle, and more particularly to a lubricating oil composition for an internal combustion engine of a hybrid vehicle that includes both an electric motor and an engine and is driven by one or both of them. The composition for an internal combustion engine is excellent in the base number maintaining property even under the condition of being mixed and accumulated, can effectively function the metal-based detergent over a long period of time, and further has good high-temperature cleanability.

  In recent years, hybrid vehicles that include both an electric motor and an engine and are driven by one or both have come into practical use. Hybrid vehicles typically use an engine as the motive power for the generator and are driven by a motor only. They are driven mainly by the motor at low speeds and driven by the engine at high speeds. There is a parallel system that assists the engine drive by motor drive during acceleration, and a series / parallel system that distributes the engine drive and motor drive in a well-balanced manner as the speed increases, with the main drive being the motor drive at the start and low speed. In these hybrid vehicles, the engine is stopped when the vehicle is stopped, and control is performed such that the engine fuel system is stopped when the vehicle is driven only by motor driving or braking. Therefore, the engine is repeatedly stopped and operated. Therefore, it can be said that the engine oil used for these is in a unique usage environment as compared with the engine oil of an automobile driven only by a conventional engine. However, the study on the lubricating oil for internal combustion engines specialized for such hybrid vehicles has not been sufficiently conducted, and the knowledge is hardly obtained.

  The inventor examined the characteristics of the internal combustion engine of the hybrid vehicle, and found that the function of the metallic detergent was easily lost in a short period of time as compared with the conventional internal combustion engine. Further, when examined in more detail, it was found that moisture mixed in the lubricating oil easily accumulates under the conditions of use of an internal combustion engine of a hybrid vehicle, particularly a parallel type or series / parallel type hybrid vehicle. It has also been found that the deterioration due to causes the calcium carbonate to become coarser and the base number of the lubricating oil to decrease remarkably. Therefore, it is essential that the lubricating oil suitable for the internal combustion engine of the hybrid vehicle is excellent in hydrolysis stability and has a high base number maintenance performance, and also maintains engine performance and extends the life of the lubricating oil. In order to achieve this, it is necessary to have high-temperature cleanliness at the time of new oil and to maintain its performance.

  Usually, in internal combustion engine lubricants, zinc dithiophosphate as an antiwear and antioxidant agent is an overbased metal detergent or ashless dispersant to enhance oxidation stability, high temperature cleanability and acid neutralization ability. Various additives such as these are blended. For lubricating oil for internal combustion engines, low phosphorus and low ash are being studied in order to avoid the influence on exhaust gas purification devices as much as possible, but for the purpose of low ash, an overbased metal detergent is simply used. If reduced, high-temperature cleanability and acid neutralization performance become insufficient. Therefore, it is important to make the metal detergent function effectively in a limited blending amount and to maintain the high temperature cleanability and acid neutralization ability at a high level for a long period of time. However, in the case of low ash oil, which mainly uses zinc dithiophosphate, it is difficult to improve the cleanliness at high temperatures, especially in conditions where moisture is easily mixed and accumulated, such as in an internal combustion engine of a hybrid vehicle. It is difficult for a basic metallic detergent to function effectively over a long period of time.

In recent years, lubricating oil compositions with excellent long drain properties such as high-temperature cleanliness and base number maintenance have been proposed as lubricating oils containing no phosphorus such as zinc dialkyl phosphate or containing phosphorus compounds with reduced sulfur. (For example, Patent Documents 1 and 2).
JP 2002-294271 A Japanese Patent No. 3662228

  The lubricating oils described in Patent Documents 1 and 2 are low-sulfur compositions having good base number maintenance and high-temperature cleanability, and can be suitably used mainly for gas engine applications. However, even when zinc dithiophosphate is mainly used, when a metal detergent with a high metal ratio is used, or when the content of metal detergent is reduced, good high-temperature cleanability and base number maintainability are required. It has been. In particular, in consideration of use in an internal combustion engine of a hybrid vehicle, it is essential to improve the base number maintainability under use conditions where water is mixed and accumulated, that is, hydrolysis conditions. Also, it is desirable to keep the high temperature cleanliness higher.

  The first of the problems of the present invention is an electric motor and / or engine that is excellent in hydrolysis stability, has excellent base number maintenance performance even under conditions where water is easily mixed and accumulates, in view of the above circumstances. It is an object of the present invention to provide a lubricating oil composition for an internal combustion engine of a hybrid vehicle to be driven, in particular, an internal combustion engine of a parallel or series / parallel hybrid vehicle in which engine stop and operation are frequently repeated.

  The second object of the present invention is to provide a lubricating oil composition for an internal combustion engine that is excellent in the above-mentioned performance and excellent in high-temperature cleanliness.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the lubricating oil composition for an internal combustion engine containing a specific additive in the lubricating base oil is remarkably excellent in hydrolysis stability, It has been found that a high base number can be maintained even under conditions where water is mixed and easily accumulates. In addition, by further selecting and combining specific lubricating base oils and additives, it was found that the lubricating oil composition for internal combustion engines is excellent not only in hydrolytic stability but also in high-temperature cleanability, and the present invention has been completed. It came to do.

  That is, according to the first aspect of the present invention, (A) a lubricant base oil, based on the total amount of the composition, (B1) 0.005 to 0.5 mass% of a salicylate detergent as a metal amount, (C2) boron (C) Succinimide-based ashless dispersant containing no succinimide-based ashless dispersant (C) 0.005-0.4% by mass with a nitrogen content of (C) succinimide-based ashless dispersant, (D) Metal salt of phosphorus-containing acid with a phosphorus content The present invention solves the above problems by providing a lubricating oil composition for an internal combustion engine of a hybrid vehicle characterized by containing 0.005 to 0.2% by mass.

  Further, according to the second aspect of the present invention, (A) the lubricant base oil is based on the total amount of the composition, (B1) 0.005 to 0.5% by mass of the salicylate-based detergent as a metal amount, (C1) The boron-containing succinimide-based ashless dispersant is 0.001-0.03% by mass as the amount of boron, and (C2) the succinimide-based ashless dispersant containing no boron is 0.005-0.4% by mass as the amount of nitrogen. And (D) providing a lubricating oil composition for an internal combustion engine of a hybrid vehicle characterized by containing 0.005 to 0.2% by mass of a metal salt of a phosphorus-containing organic acid as a phosphorus amount. To do.

  2nd aspect WHEREIN: The mass ratio (B / N ratio) of the total nitrogen content resulting from the said (C1) component and (C2) component, and the boron content resulting from the said (C1) component is 0.05. It is preferable that it is -0.3.

  In the first and second embodiments, the component (B1) is preferably a metal salt of an alkyl salicylic acid including a dialkyl salicylic acid and / or a (over) basic salt thereof.

  The lubricating oil composition for an internal combustion engine of the present invention is very excellent in hydrolysis stability, and can maintain a high base number even under conditions where water is easily mixed and accumulated. Moreover, since the lubricating oil composition for internal combustion engines of the present invention has good high temperature cleanliness, it is possible to maintain engine performance and extend the life of the lubricating oil. Therefore, not only can it be suitably used for an internal combustion engine of a hybrid vehicle driven by an electric motor and / or an engine, in particular, a parallel or series-parallel hybrid vehicle in which engine stop and operation are frequently repeated, In addition, it is also suitable for use in marine internal combustion engines such as outboard motors that are operated under conditions in which moisture does not easily evaporate, gas engines that are likely to contain a large amount of moisture, gasoline engines that have idling stop control, diesel engines, etc. be able to.

  Such an operation and gain of the present invention will be made clear from the best mode for carrying out the invention described below.

Hereinafter, the lubricating oil composition of the present invention will be described in detail.
The component (A) in the lubricating oil composition of the present invention is a lubricating base oil, and a mineral base oil and / or a synthetic base oil used for ordinary lubricating oils can be used.

  Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Produced by a method of isomerizing wax isomerized mineral oil, GTL WAX (Gas Liquid Wax), refined by one or more treatments such as hydroisomerization, solvent dewaxing, catalytic dewaxing, hydrorefining, etc. Base oil and the like.

  Specific examples of synthetic base oils include polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate Diesters such as diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; neopentyl glycol ester, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol Examples thereof include polyol esters such as pelargonate; aromatic synthetic oils such as alkyl naphthalene, alkyl benzene, and aromatic esters, or mixtures thereof.

  As the (A) lubricating base oil in the present invention, the mineral base oil, the synthetic base oil, or an arbitrary mixture of two or more selected from these can be used. Examples thereof include one or more mineral base oils, one or more synthetic base oils, a mixed oil of one or more mineral base oils and one or more synthetic base oils, and the like.

As the (A) the lubricating base oil of the present invention is not particularly limited in its nature, a kinematic viscosity at 100 ° C. is preferably 1 to 8 mm ² / s, more preferably 3 to 6 mm ² / s The kinematic viscosity at 40 ° C. is preferably 5 to 100 mm ² / s, preferably 15 to 40 mm ² / s, and the viscosity index is preferably 90 or more, more preferably 100 or more, and its% C _P ( (Described later) is preferably 60 or more, more preferably 70 or more, and its% C _N (described later) is preferably 40 or less, more preferably 30 or less, and% C _P /% C _N is preferably 1.5. More preferably, it is 2 or more, its pour point is -10 ° C or lower, preferably -15 ° C or lower, and its NOACK evaporation (described later) is preferably 2 to 70% by mass, more preferably 5 to 25%. The aniline point is preferably 80 ° C. or more, more preferably 95 ° C. or more, and the sulfur content is preferably 0.3% by mass or less, more preferably 0.15% by mass or less. The nitrogen content is preferably 20 ppm by mass or less, more preferably 10 ppm by mass or less, and the iodine value thereof is preferably 10 or less, more preferably 6 or less.

As the (A) lubricating base oil of the present invention, (A1) a kinematic viscosity at 100 ° C. is 1 to 8 mm ² / s, a pour point is −15 ° C. or less, an aniline point is 100 ° C. or more, Is 40 mass% or more, the monocyclic naphthene content is 25 mass% or less, the 2-6 cyclic naphthene content is 35 mass% or less, and the iodine value is 2 or less. It is preferable to contain a lubricating base oil of 3% or more as a main component. In this case, the content of the component (A1) is preferably 50 to 100% by mass, more preferably 70% by mass or more, and further preferably 85% by mass or more, based on the total amount of the lubricating base oil.

(A1) a kinematic viscosity at 100 ° C. of component is 1 to 8 mm ² / s, preferably 3 to 6 mm ² / s, more preferably 3.5~5mm ² / s, more preferably from 3.8 to 4 Desirably, it is 5 mm ² / s. When the kinematic viscosity at 100 ° C. of the component (A1) exceeds 8 mm ² / s, the low-temperature viscosity characteristic deteriorates. On the other hand, when the kinematic viscosity is less than 1 mm ² / s, formation of an oil film at the lubrication site is not possible. Since it is sufficient, the lubricity is inferior, and the evaporation loss of the lubricating base oil increases, which is not preferable. Also, (A1) a kinematic viscosity at 40 ° C. of components, for the same reason, preferably 5 to 100 mm ² / s, more preferably 10 to 40 mm ² / s, more preferably 15 to 25 mm ² / s, in particular Preferably it is 16-22 mm < ² > / s.

  The pour point of the component (A1) is −15 ° C. or lower, preferably −17.5 ° C. or lower, and the lower limit is not particularly limited, but is preferable in terms of low temperature viscosity characteristics and economy in the dewaxing process. Is −45 ° C. or higher, more preferably −30 ° C. or higher, further preferably −25 ° C. or higher, particularly preferably −20 ° C. or higher. By setting the pour point of the component (A1) to −15 ° C. or less, a lubricating oil composition having excellent low-temperature viscosity characteristics can be obtained. As the dewaxing step, either solvent dewaxing or contact dewaxing may be applied, but the low temperature viscosity characteristics can be further improved even when the pour point is not less than the above particularly preferred lower limit, and the high temperature cleanliness. In particular, it is preferably a contact dewaxing step in terms of excellent hydrolytic stability.

  The aniline point of the component (A1) is 100 ° C. or higher, more preferably 104 ° C. or higher, more preferably 108 ° C. or higher in that a lubricating oil composition excellent in high-temperature cleanliness and hydrolysis stability can be obtained. The upper limit is not particularly limited, and may be 125 ° C. or higher as one embodiment of the present invention, but is preferably 125 ° C. or lower in terms of being excellent in solubility of additives and sludge, and being excellent in compatibility with a sealing material. Preferably it is 120 degrees C or less.

  The paraffin content in the saturated content of the component (A1) is 40% by mass or more, preferably 47% by mass or more, from the viewpoint of improving high-temperature cleanliness and hydrolysis stability, and there is no particular limitation on the upper limit value. However, it may be 70% by mass or more as one embodiment of the present invention, but it is preferably 70% by mass or less from the viewpoint of superior solubility of additives and sludge. In this case, low-temperature viscosity characteristics, high-temperature cleanliness and hydrolytic stability Is more preferably 65% by mass or less, still more preferably 60% by mass or less, and particularly preferably 57% by mass or less.

  The naphthene content (1-6 ring naphthene content) in the saturated content of the component (A1) is 60% by mass or less, preferably 53% by mass or less, depending on the paraffin content, and the lower limit thereof is not particularly limited. Although it may be 30% by mass or less as one embodiment of the present invention, it is preferably 30% by mass or more because it is more excellent in solubility of additives and sludges. In this case, low-temperature viscosity characteristics, high-temperature cleanability and hydrolysis stability are preferred. Is more preferably 35% by mass or more, further preferably 40% by mass or more, and further preferably 43% by mass or more.

  (A1) The monocyclic naphthene content in the saturated content of the component (A1) is 25% by mass or less, preferably 23% by mass or less, and the lower limit thereof is not particularly limited. Although it is good, it is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 18% by mass or more from the viewpoint of superior solubility in additives and sludge.

  The 2-6 ring naphthene content in the saturated component of the component (A1) is 35% by mass or less, preferably 32% by mass or less, and the lower limit thereof is not particularly limited, and 10% by mass as one embodiment of the present invention. However, it is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more in terms of excellent solubility in additives and sludge.

  The total amount of paraffin and monocyclic naphthene in the saturated component of component (A1) is not particularly limited, but is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 65% by mass. As described above, it is particularly preferably 68% by mass or more, and may be 90% by mass or more as one embodiment of the present invention, but is preferably 90% by mass or less, more preferably 80% by mass in terms of superior solubility of additives and sludge. % Or less, more preferably 76% by mass or less.

  Further, the ratio of the paraffin content in the saturated component (A1) to the monocyclic naphthene component in the saturated component (paraffin content / single-ring naphthene component) is not particularly limited, and is 10 or more as one aspect of the present invention. However, it is preferably 10 or less in terms of excellent solubility in additives and sludge, in this case, more preferably 5 or less, even more preferably 3.5 or less, particularly in terms of excellent low-temperature viscosity characteristics. Preferably it is 3.0 or less.

  In addition, the paraffin content and the naphthene content in the saturated content referred to in the present invention are an alkane content (unit: mass%) and a naphthene content (measurement target: 1 ring to 6) measured in accordance with ASTM D 2786-91, respectively. Ring naphthene, unit: mass%).

  Further, the iodine value of the component (A1) is 2 or less, preferably 1 or less, more preferably 0.7 or less, further preferably 0.5 or less, particularly preferably 0.1 or less, and 0 Although it may be less than .001, it is preferably 0.001 or more, and more preferably 0.01 or more, from the viewpoint of small effects that are commensurate with it and economy. By setting the iodine value of the lubricating base oil to 2 or less, high-temperature cleanability and hydrolysis stability can be improved. The “iodine value” in the present invention means an iodine value measured by an indicator titration method of JIS K 0070 “acid value, saponification value, iodine value, hydroxyl value, and unsaponification value of a chemical product”. .

  The proportion of tertiary carbon in the total amount of constituent carbon of component (A1) is 6.3% or more, preferably 12% or less, more preferably 6.6 to 10%, and still more preferably 7%. .2 to 9%, particularly preferably 7.5 to 8.5%. By setting the proportion of tertiary carbon within the above range, it is possible to obtain a lubricating base oil having excellent viscosity temperature characteristics, high temperature cleanability and hydrolysis stability. Here, the “ratio of tertiary carbon” is the ratio of carbon atoms due to> CH— (methine group bonded to three carbon atoms) in the total amount of constituent carbon, that is, due to branching or naphthene. It means the proportion of carbon atoms.

Here, “the ratio of the tertiary carbon to the total amount of the constituent carbon of the component (A1)” is the sum of the integrated intensities caused by the tertiary carbon with respect to the total integrated intensities of all the carbons measured by ¹³ C-NMR. Means the percentage of That is, (a) the total integrated intensity of about 10 to 50 ppm chemical shift (total integrated intensity attributable to all constituent carbons), and (c) 27.9 to 28.1 ppm chemical shift, 28.4 to 28.6 ppm chemical shift , 32.6 to 33.2 ppm, 34.4 to 34.6 ppm, 37.4 to 37.6 ppm, 38.8 to 39.1 ppm, 40.4 to 40.6 ppm of integrated intensity (methyl group, ethyl Is the ratio (%) of (c) when (a) is defined as 100%.

In this specification, the measurement of ¹³ C-NMR is carried out by dissolving a 0.5 g sample in 3 g of deuterated chloroform by a gated decoupling method at room temperature and a resonant frequency of 100 MHz. (A1) For the calculation of the ratio of tertiary carbon to the total amount of constituent carbon of the component, other measurement conditions may be used as long as the correct result is obtained, and even if not measured by ¹³ C-NMR, the same Other measurement methods may be used as long as the result is obtained.

Moreover,% C _A of Component (A1) is not particularly limited, heat and oxidation stability and viscosity-temperature characteristics, is 2 or less in viewpoint of increasing the high temperature detergency and hydrolytic stability, preferably 1 or less, more preferably 0.5 or less, particularly preferably 0.2 or less.

Furthermore, (A1)% C _P of the components is not particularly limited, heat and oxidation stability and viscosity-temperature characteristics, in that it is possible to further improve the high-temperature detergency and hydrolytic stability, preferably 70 or more, More preferably, it is 75 or more, more preferably 80 or more, and there is no particular limitation on the upper limit, and it may be 90 or more as one embodiment of the present invention, but preferably 90 or less from the viewpoint of superior solubility of additives and sludge. More preferably, it is 85 or less.

Furthermore, (A1)% C _N of the components is not particularly limited, heat and oxidation stability and viscosity-temperature characteristics, in that it is possible to further improve the high-temperature detergency and hydrolytic stability, preferably 28 or less, More preferably, it is 25 or less, and the lower limit thereof is not particularly limited, and may be less than 10 as one aspect of the present invention, but is preferably 10 or more, more preferably 15 or more in terms of excellent solubility of additives and sludge. It is.

Further, the _{(A1)% C P /%} C N of the components is not particularly limited, heat and oxidation stability and viscosity-temperature characteristics in that it can be increased, preferably 2 or more, more preferably 2 4 or more, particularly preferably 4.0 or more, and the upper limit thereof is not particularly limited, and may be 5 or more as one embodiment of the present invention, but is preferably from the viewpoint of superior solubility of additives and sludge. 5 or less, more preferably 4.5 or less.

Herein, the _term% C A,% _C A _P and% _{C N,} is determined by a method in accordance with ASTM D 3238-85, respectively (n-d-M ring analysis), the total number of carbon atoms of the aromatic carbon atoms Mean percentage of paraffin carbon to total carbon and percentage of naphthene carbon to total carbon.

  Although there is no restriction | limiting in particular about content of the saturated part of (A1) component, Preferably it is 90 mass% at the point which can improve thermal / oxidation stability, a viscosity temperature characteristic, high temperature detergency, and hydrolysis stability. More preferably, it is 94 mass% or more, More preferably, it is 98 mass% or more, Most preferably, it is 99 mass% or more.

  Further, the content of the aromatic component of the component (A1) is not particularly limited, but is preferably from the viewpoint that the heat / oxidation stability and the viscosity temperature characteristic, the high temperature cleanliness and the hydrolysis stability can be further improved. It is 10 mass% or less, More preferably, it is 6 mass% or less, More preferably, it is 2 mass% or less, Most preferably, it is 1 mass% or less.

  In addition, content of a saturated content and aromatic content as used in the field of this invention means the value (unit: mass%) measured based on ASTM D 2007-93.

  Although there is no restriction | limiting in particular about the sulfur content of (A1) component, Preferably it is 0.1 mass% or less, More preferably, it is 0.05 mass% or less, More preferably, it is 0.01 mass% or less, Most preferably, it is 0.001. It is desirable that it is less than mass%.

  Although there is no restriction | limiting in particular about the nitrogen content of (A1) component, Preferably it is 5 mass ppm or less at the point which can obtain the composition which is more excellent in thermal / oxidation stability, high temperature detergency, and hydrolysis stability. More preferably, it is 3 mass ppm or less.

  The viscosity index of the component (A1) is not particularly limited, but is preferably 100 or more, more preferably in view of obtaining a composition excellent in thermal / oxidative stability, high-temperature cleanability and hydrolysis stability. Is 110 or more, more preferably 115 or more, and particularly preferably 120 or more. One embodiment of the present invention may be 135 or more, but is preferably 135 or less, more preferably in terms of superior solubility of additives and sludge. 130 or less.

  Although it does not restrict | limit especially about the amount of NOACK evaporation of (A1) component, Preferably it is 2-25 mass%, More preferably, it is 5-20 mass%, More preferably, it is 10-15 mass%. Setting the amount of NOACK evaporation of the component (A1) in the above range is particularly preferable because high-temperature cleanliness, hydrolysis stability, low-temperature viscosity characteristics, wear prevention, and fatigue life can be improved in a balanced manner. In addition, the NOACK evaporation amount as used in the field of this invention means the evaporation loss amount measured based on ASTM D 5800-95.

As long as the component (A1) has the above properties, the production method is not particularly limited, but specific examples of the lubricating base oil according to the present invention include the following base oils (1) to (1) to (A1) List the base oil obtained by using (8) as a raw material, purifying the raw oil and / or the lubricating oil fraction recovered from the raw oil by a predetermined refining method, and recovering the lubricating oil fraction. Can do.
(1) Distilled oil by atmospheric distillation of paraffinic crude oil and / or mixed base crude oil (2) Distilled oil by vacuum distillation of atmospheric distillation residue of paraffinic crude oil and / or mixed base crude oil ( WVGO)
(3) Wax (slack wax, etc.) obtained by the lubricant dewaxing process and / or synthetic wax (Fischer-Tropsch wax, GTL wax, etc.) obtained by the gas-to-liquid (GTL) process, etc.
(4) One or two or more mixed oils selected from base oils (1) to (3) and / or mild hydrocracking treatment oils of the mixed oils (5) selected from base oils (1) to (4) 2 or more kinds of mixed oils (6) Base oil (1), (2), (3), (4) or (5) debris oil (DAO)
(7) Mild hydrocracking treatment oil (MHC) of base oil (6)
(8) Two or more mixed oils selected from base oils (1) to (7)

  The above-mentioned predetermined purification methods include hydrorefining such as hydrocracking and hydrofinishing; solvent refining such as furfural solvent extraction; dewaxing such as solvent dewaxing and catalytic dewaxing; acid clay and activated clay White clay purification; chemical (acid or alkali) cleaning such as sulfuric acid cleaning and caustic soda cleaning is preferable. In the present invention, one of these purification methods may be performed alone, or two or more may be combined. Moreover, when combining 2 or more types of purification methods, the order in particular is not restrict | limited, It can select suitably.

Furthermore, as the component (A1), the following base oil obtained by performing a predetermined treatment on a base oil selected from the above base oils (1) to (8) or a lubricating oil fraction recovered from the base oil ( 9) or (10) is particularly preferred.
(9) The base oil selected from the base oils (1) to (8) or the lubricating oil fraction recovered from the base oil is hydrocracked and recovered from the product or the product by distillation or the like. Hydrocracked mineral oil obtained by performing dewaxing treatment such as solvent dewaxing or catalytic dewaxing on the lubricating oil fraction, or distillation after the dewaxing treatment (10) The above base oils (1) to (8) ) Or a lubricating oil fraction recovered from the base oil is hydroisomerized, and the product or the lubricating oil fraction recovered from the product by distillation or the like is subjected to solvent dewaxing or catalytic dewaxing. Hydroisomerized mineral oil obtained by performing dewaxing treatment such as or by distillation after the dewaxing treatment

  When obtaining the lubricating base oil of (9) or (10) above, as the dewaxing step, the thermal / oxidative stability and low temperature viscosity characteristics can be further enhanced, and the fatigue prevention performance of the lubricating oil composition is further enhanced. It is particularly preferable to include a contact dewaxing step. Moreover, when obtaining the lubricating base oil of (9) or (10) above, a solvent refining treatment and / or a hydrofinishing treatment step may be further provided as necessary.

  The catalyst used for the hydrocracking / hydroisomerization is not particularly limited, but a composite oxide having cracking activity (for example, silica alumina, alumina boria, silica zirconia, etc.) or one or more of the composite oxides Hydrocracking catalyst in which a metal having a hydrogenation ability (for example, one or more metals such as Group VIa metal and Group VIII metal in the periodic table) supported by a binder combined with a binder is supported Or a hydroisomerization catalyst in which a support containing zeolite (for example, ZSM-5, zeolite beta, SAPO-11, etc.) is loaded with a metal having a hydrogenation ability including at least one of Group VIII metals. Preferably used. The hydrocracking catalyst and hydroisomerization catalyst may be used in combination by lamination or mixing.

The reaction conditions in the hydrocracking / hydroisomerization are not particularly limited, but the hydrogen partial pressure is 0.1 to 20 MPa, the average reaction temperature is 150 to 450 ° C., the LHSV is 0.1 to 3.0 hr ⁻¹ , the hydrogen / oil ratio. It is preferable to set it as 50-20000 scf / b.

  In the case of catalytic dewaxing (catalyst dewaxing), the hydrocracking / isomerization product oil is reacted with hydrogen in the presence of a suitable dewaxing catalyst under conditions effective to lower the pour point. In catalytic dewaxing, some of the high-boiling substances in the cracking / isomerization product are converted to low-boiling substances, the low-boiling substances are separated from the heavier base oil fraction, and the base oil fraction is fractionated. Two or more kinds of lubricating base oils are obtained. The low-boiling substances can be separated before obtaining the target lubricating base oil or during fractional distillation.

  The dewaxing catalyst is not particularly limited as long as it can lower the pour point of the cracked / isomerized product oil, but the desired lubricating base oil is obtained from the cracked / isomerized product oil in a high yield. Those that can be used are preferred. As such a dewaxing catalyst, a shape selective molecular sieve (molecular sieve) is preferable, and specifically, ferrierite, mordenite, ZSM-5, ZSM-11, ZSM-23, ZSM-35, ZSM-22 ( And thealuminophosphates (SAPO) and the like. These molecular sieves are preferably used in combination with a catalytic metal component, and more preferably in combination with a noble metal. A preferable combination includes, for example, a composite of platinum and H-mordenite.

The dewaxing conditions are not particularly limited, but the temperature is preferably 200 to 500 ° C., and the hydrogen pressure is preferably 10 to 200 bar (1 MPa to 20 MPa). Also, in the case of flow-through reactor, _{H 2} processing speed is preferably 0.1~10kg / l / hr, LHSV is preferably 0.1 to 10 ^-1, more preferably 0.2～2.0H ^-1 . Dewaxing refers to a substance having an initial boiling point of 350 to 400 ° C., usually 40% by mass or less, preferably 30% by mass or less, contained in the cracked / isomerized product oil, having a boiling point lower than the initial boiling point. It is preferable to carry out the conversion to a substance having the same.

The (A) lubricating base oil of the present invention is a lubricating base oil composed of the component (A1) or a mixed base oil of the component (A1) and the mineral base oil or synthetic base oil. preferably, a kinematic viscosity at 100 ° C., as described above, preferably 1 to 8 mm ² / s, more preferably at 3 to 6 mm ² / s, more preferably 3.5~6mm ² / s, further Preferably, the viscosity index is adjusted to 3.8 to 4.5 mm ² / s, and the viscosity index is preferably 90 or more, more preferably 100 or more, more preferably 110 or more, and further preferably 115 or more. .

  Component (B) in the lubricating oil composition of the present invention is a metallic detergent. In the present invention, it is necessary to use the (B1) salicylate detergent because it is particularly excellent in hydrolysis stability and also excellent in high temperature cleanability.

  (B1) The salicylate detergent is not particularly limited in its structure, but is a metal salt of salicylic acid having 1 to 2 alkyl groups having 1 to 40 carbon atoms, preferably an alkali metal salt or alkaline earth metal salt, In particular, a magnesium salt and / or a calcium salt is preferably used.

  As the component (B1) in the present invention, those containing a dialkyl salicylic acid metal salt are preferred in that they are superior in terms of high-temperature cleanability and hydrolysis stability, that is, the constituent ratio of the dialkyl salicylic acid metal salt exceeds 0 and is preferably 100 mol% or less. Is preferably 5 mol% or more, more preferably 10 mol% or more. On the other hand, as the component (B1) in the present invention, it is preferable that the component ratio of the monoalkyl salicylic acid metal salt is higher in terms of excellent low-temperature viscosity characteristics, for example, the component ratio of the monoalkyl salicylic acid metal salt is 85 to 100 mol%, It is an alkyl salicylic acid metal salt in which the constituent ratio of the dialkyl salicylic acid metal salt is 0 to 15 mol% and the constituent ratio of the 3-alkyl salicylic acid metal salt is 40 to 100 mol% and / or its (over) basic salt. Is preferred.

  The monoalkyl salicylic acid metal salt here means an alkyl salicylic acid metal salt having one alkyl group such as a 3-alkyl salicylic acid metal salt, a 4-alkyl salicylic acid metal salt, a 5-alkyl salicylic acid metal salt, and the like. The constituent ratio of the salt is 85 to 100 mol%, preferably 88 to 98 mol%, more preferably 90 to 95 mol% with respect to 100 mol% of the alkylsalicylic acid metal salt, and an alkylsalicylic acid metal salt other than the monoalkylsalicylic acid metal salt, for example, The composition ratio of the dialkyl salicylic acid metal salt is 0 to 15 mol%, preferably 2 to 12 mol%, and more preferably 5 to 10 mol%. Moreover, the structural ratio of 3-alkyl salicylic acid metal salt is 40-100 mol% with respect to 100 mol% of alkyl salicylic acid metal salt, Preferably it is 45-80 mol%, More preferably, it is 50-60 mol%. The total composition ratio of the 4-alkyl salicylic acid metal salt and the 5-alkyl salicylic acid metal salt corresponds to the composition ratio excluding the 3-alkyl salicylic acid metal salt and the dialkyl salicylic acid metal salt with respect to 100 mol% of the alkyl salicylic acid metal salt. And 0 to 60 mol%, preferably 20 to 50 mol%, more preferably 30 to 45 mol%. By containing a small amount of a metal salt of dialkyl salicylic acid, it is possible to obtain a composition that is excellent in high-temperature cleanliness and low-temperature characteristics and excellent in hydrolytic stability. By setting the composition ratio of 3-alkyl salicylate to 40 mol% or more, 5 -The composition ratio of the alkyl salicylic acid metal salt can be relatively lowered, and the oil solubility can be improved.

  Moreover, as an alkyl group in the alkyl salicylic acid metal salt which comprises a (B1) salicylate type detergent, it is C10-40, Preferably it is C10-19 or C20-30, More preferably, it is C14-18. Or it is a C20-C26 alkyl group, Most preferably, it is a C14-18 alkyl group. Examples of the alkyl group having 10 to 40 carbon atoms include decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, heicosyl, docosyl, Examples thereof include alkyl groups having 10 to 40 carbon atoms such as a tricosyl group, a tetracosyl group, a pentacosyl group, a hexacosyl group, a heptacosyl group, an octacosyl group, a nonacosyl group, and a triacontyl group. These alkyl groups may be linear or branched, and may be a primary alkyl group, a secondary alkyl group, or a tertiary alkyl group. In the present invention, the desired metal salicylate is used. A secondary alkyl group is particularly preferred from the viewpoint of easily obtaining a salt.

  Examples of the metal in the alkyl salicylic acid metal salt include alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, and are preferably calcium and magnesium, and particularly preferably calcium.

  Component (B1) can be produced by a known method and the like, and is not particularly limited. For example, 1 mol or more of a polymer or copolymer such as ethylene, propylene, or butene with respect to 1 mol of phenol. A method of alkylating with a C10-40 olefin, preferably a linear α-olefin such as an ethylene polymer, and carboxylating with carbon dioxide or the like, or 1 mol or more of the olefin per 1 mol of salicylic acid, preferably Reacts with a metal base such as an alkali metal or alkaline earth metal oxide or hydroxide to an alkyl salicylic acid mainly composed of a monoalkyl salicylic acid obtained by an alkylation method using the linear α-olefin. Or an alkali metal salt such as sodium salt or potassium salt, It can be obtained by replacing an alkali metal salt with an alkaline earth metal salt. Here, the reaction ratio of phenol or salicylic acid and olefin is preferably controlled to, for example, 1: 1 to 1.15 (molar ratio), more preferably 1: 1.05 to 1.1 (molar ratio). The composition ratio of the monoalkyl salicylic acid metal salt and the dialkyl salicylic acid metal salt can be controlled to a desired ratio, and by using a linear α-olefin as the olefin, a 3-alkyl salicylic acid metal salt and a 5-alkyl salicylic acid metal It is particularly preferable because the constituent ratio of the salt and the like can be easily controlled to a desired ratio of the present application and an alkyl salicylic acid metal salt having a secondary alkyl which is preferable in the present invention can be obtained as a main component. In addition, when a branched olefin is used as the olefin, it is easy to obtain only a 5-alkyl salicylic acid metal salt, but the oil solubility is improved by mixing a 3-alkyl salicylic acid metal salt or the like so as to have the desired configuration of the present application. This is an unfavorable method because the manufacturing process is diversified.

  The component (B1) is an alkali metal or alkaline earth gold salicylate (neutral salt) obtained as described above, an excess of an alkali metal or alkaline earth metal salt, an alkali metal or an alkaline earth metal base ( A basic salt obtained by heating an alkali metal or alkaline earth metal hydroxide or oxide) in the presence of water, or the neutral salt in the presence of carbon dioxide, boric acid or borate. Also included are overbased salts obtained by reacting with a base such as an alkali metal or alkaline earth metal hydroxide.

  These reactions are usually carried out in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricating base oil, etc.), and the metal content thereof is 1.0 to It is desirable to use 20% by mass, preferably 2.0 to 16% by mass.

  As the most preferable component (B1) in the present invention, the composition ratio of the monoalkyl salicylic acid metal salt is 85 to 95 mol%, and the metal dialkyl salicylate is superior in terms of the balance between high temperature cleanliness, hydrolysis stability and low temperature viscosity characteristics. Alkyl salicylic acid having a salt composition ratio of 5 to 15 mol%, a composition ratio of 3-alkyl salicylic acid metal salt of 50 to 60 mol%, and a composition ratio of 4-alkyl salicylic acid metal salt and 5-alkyl salicylic acid metal salt of 35 to 45 mol% Metal salts and / or their (over) basic salts. The alkyl group here is particularly preferably a secondary alkyl group.

  In the present invention, the base number of the component (B1) is usually 0 to 500 mgKOH / g, preferably 20 to 300 mgKOH / g, particularly preferably 100 to 200 mgKOH / g, particularly preferably 150 to 200 mgKOH / g. One or two or more selected from among them can be used in combination. The base number referred to here is 7. JIS K2501 “Petroleum products and lubricating oils-Neutralization number test method”. Means the base number measured by the perchloric acid method according to the above.

  In the present invention, as the component (B), other metal detergents can be used in combination with the component (B1) which is a salicylate detergent. Examples of other metal detergents include sulfonate detergents and phenates. System detergents, carboxylate detergents, and the like.

  The structure of the sulfonate detergent is not particularly limited. For example, an alkali metal salt of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 100 to 1,500, preferably 200 to 700. Alternatively, alkaline earth metal salts are exemplified, and particularly, magnesium salts and / or calcium salts are preferably used. Specific examples of alkyl aromatic sulfonic acids include so-called petroleum sulfonic acids and synthetic sulfonic acids. As the petroleum sulfonic acid, those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil or so-called mahoganic acid which is produced as a by-product when white oil is produced is used. Synthetic sulfonic acids include, for example, alkylbenzenes having linear or branched alkyl groups that are obtained as a by-product from an alkylbenzene production plant that is a raw material for detergents, or are obtained by alkylating polyolefin to benzene. As a raw material, a sulfonated one or a sulfonated dinonylnaphthalene is used. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but usually fuming sulfuric acid or sulfuric acid is used.

  Further, as the alkaline earth metal sulfonate, the above alkyl aromatic sulfonic acid can be directly reacted with an alkaline earth metal base such as magnesium and / or calcium alkaline earth metal oxide or hydroxide, or Not only neutral alkaline earth metal sulfonates obtained by replacing alkali metal salts such as sodium salts and potassium salts with alkaline earth metal salts, but also neutral alkaline earth metal sulfonates and excess alkaline earth. Of alkaline earth metal salts and alkaline earth metal bases (hydroxides and oxides) obtained by heating in the presence of water, basic alkaline earth metal sulfonates, carbon dioxide and / or boric acid or borates Obtained by reacting the neutral alkaline earth metal sulfonate with an alkaline earth metal base in the presence of Salts overbased alkaline earth metal sulfonate, it is also included borate overbased alkaline earth metal sulfonate.

  In the present invention, the neutral alkaline earth metal sulfonate, the basic alkaline earth metal sulfonate, the overbased alkaline earth metal sulfonate, a mixture thereof, and the like can be used as the sulfonate detergent. As the sulfonate detergent, calcium sulfonate detergent and magnesium sulfonate detergent are preferable, and calcium sulfonate detergent is particularly preferable.

  Sulfonate detergents are usually commercially available in a state diluted with a light lubricating base oil or the like, and are available, but generally the metal content is 1.0 to 20% by mass, preferably Is preferably 2.0 to 16% by mass.

  The base number of the sulfonate detergent used in the present invention is arbitrary, and is usually 0 to 500 mgKOH / g. However, the base number is 0 to 400 mgKOH / g, preferably 200 to 400 mgKOH / g from the viewpoint of excellent high-temperature cleanability. More preferably, it is desirable to use 250 to 350 mg KOH / g. The base number referred to here is JIS K2501 “Petroleum products and lubricating oils-Neutralization number test method”. It means the base number by the perchloric acid method measured according to the above.

  Specifically, the phenate detergent is obtained by reacting sulfur with an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. Alkali earth metal salts, particularly magnesium salts and / or calcium salts, of Mannich reaction products of alkylphenols obtained by reacting alkylphenol sulfides or alkylphenols with formaldehyde are preferably used. The base number of the phenate detergent is usually 0 to 500 mgKOH / g, preferably 20 to 450 mgKOH / g, more preferably 150 to 300 mgKOH / g.

  In the lubricating oil composition of the present invention, the content of the component (B) (the total amount in the case where a metallic detergent other than the component (B1) is also used) is 0.005 as a metal amount based on the total amount of the composition. It is -0.5 mass%, Preferably it is 0.01-0.3 mass%, More preferably, it is 0.04-0.25 mass%, Most preferably, it is 0.16-0.24 mass%.

  The component (C) in the lubricating oil composition of the present invention is a succinimide ashless dispersant. Examples of the succinimide-based ashless dispersant include succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms, more preferably 60 to 350 carbon atoms in the molecule, and boron in the succinimide. Acid or borate, 2-30 monocarboxylic acid (fatty acid, etc.), oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc., polycarboxylic acid having 2-30 carbons, phosphoric acid, phosphorous acid, The derivative | guide_body modified | denatured combining 1 type, or 2 or more types of modification | denaturation chosen from phosphorus containing acids, such as acidic (sub) phosphate ester, and a sulfur containing compound can be mentioned. The succinimide may be mono-type or bis-type, but bis-type is particularly preferable.

  The alkyl group or alkenyl group having 40 to 400 carbon atoms may be linear or branched, but is preferably branched, and more specifically, olefins such as propylene, 1-butene and isobutylene. And branched alkyl groups and branched alkenyl groups having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, derived from the above oligomers and ethylene / propylene co-oligomers. When the alkyl group or alkenyl group has less than 40 carbon atoms, it is difficult to obtain an effect as an ashless dispersant for the compound. On the other hand, when the alkyl group or alkenyl group has more than 400 carbon atoms, the composition has low temperature fluidity. It tends to get worse.

  The content of the component (C) in the lubricating oil composition of the present invention is preferably 0.005 to 0.4 as the amount of nitrogen on the basis of the total amount of the composition in that it is easy to achieve both high temperature cleanliness and hydrolysis stability. The mass% is more preferably 0.01 to 0.2 mass%, still more preferably 0.08 to 0.15 mass%.

  In the present invention, a succinimide-based ashless dispersant which does not contain at least (C2) boron is used as the component (C).

  When only the component (C2) is used as the component (C), it is possible to obtain a lubricating oil composition that is excellent in hydrolysis stability and has a significantly improved base number maintenance performance in the presence of moisture. In this case, the content of the component (C2) is 0.005 to 0.4% by mass as the amount of nitrogen on the basis of the total amount of the composition, but is preferably 0.01 to in terms of particularly excellent hydrolysis stability. It is 0.2% by mass, more preferably 0.08 to 0.18% by mass, and particularly preferably 0.12 to 0.15% by mass.

  In addition to the component (C2) as the component (C), it is also preferable to use (C1) a boron-containing succinimide ashless dispersant. By using the component (C2) and the component (C1) in combination, it is possible to improve the high-temperature cleanability as well as the base number maintenance performance in the presence of moisture, and to obtain a lubricating oil composition in which both performances are balanced. .

  Here, the boron content in the component (C1) is not particularly limited and is usually 0.01 to 4% by mass, but is preferably 0.1 to 2 in terms of the balance between hydrolysis stability and high temperature cleanliness. 0.5% by mass, more preferably 0.2-1% by mass, still more preferably 0.4-0.8% by mass, and for the same reason, the boron content and the nitrogen content in the component (C1) The mass ratio (B / N ratio) is generally 0.01 to 2, preferably 0.1 to 1, more preferably 0.2 to 0.5, and particularly preferably 0.3 to 0.4. It is desirable to use something.

  The content of the component (C1) when the component (C1) and the component (C2) are used in combination is 0.03% by mass or less as the boron content based on the total amount of the composition in terms of excellent hydrolysis stability. Is more preferably 0.025% by mass or less, and the amount of boron is preferably 0.001% by mass or more, more preferably 0.005% by mass or more in that the high-temperature cleanability can be further improved. More preferably, the content is 0.01% by mass or more, and particularly preferably 0.015% by mass or more. When the boron content exceeds 0.03% by mass, hydrolysis stability is greatly deteriorated, which is not preferable.

  In addition, when the component (C1) and the component (C2) are used in combination, the content of the component (C2) is 0.005 to 0.4% by mass as the amount of nitrogen on the basis of the total amount of the composition. In terms of superiority, it is preferably 0.01 to 0.2% by mass, more preferably 0.03 to 0.15% by mass, and particularly preferably 0.04 to 0.08% by mass.

  Mass ratio of boron content resulting from (C1) component and total nitrogen content resulting from (C1) component and (C2) component (B / N) when (C1) component and (C2) component are used in combination The ratio) is not particularly limited, but is preferably 0.05 to 1.2, more preferably 0.05 to 0.3, from the viewpoint of the balance between the base number maintenance performance in the presence of moisture and high temperature cleanliness. More preferably, it is 0.1-0.25, Most preferably, it is 0.15-0.2.

  Component (D) in the lubricating oil composition of the present invention is a metal salt of a phosphorus-containing acid. The metal salt of the phosphorus-containing acid is not particularly limited as long as it is a metal salt of an acidic compound containing phosphorus in the molecule. For example, the metal salt of the phosphorus compound represented by the general formula (1) or a derivative thereof, It is preferably at least one compound selected from the group consisting of a metal salt of a phosphorus compound represented by the general formula (2) or a derivative thereof, a salt or complex of a nitrogen-containing compound thereof, and a derivative thereof.

In Formula (1), X ¹ , X ² and X ³ each independently represent an oxygen atom or a sulfur atom, and R ¹⁰ , R ¹¹ and R ¹² each independently represent a hydrogen atom or a carbon atom having 1 to 30 carbon atoms. Indicates a hydrogen group.

In the formula (2), X ⁴ , X ⁵ , X ⁶ and X ⁷ are each independently an oxygen atom or a sulfur atom (one or two of X ⁴ , X ⁵ and X ⁶ are a single bond or (poly) oxyalkylene) R ¹³ , R ¹⁴ and R ¹⁵ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.

Examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ^{10 to} R ¹⁵ include an alkyl group, a cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkyl group, an aryl group, an alkyl-substituted aryl group, and an arylalkyl group. Preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms, and more preferably an alkyl group having 4 to 12 carbon atoms. is there. These hydrocarbon groups may contain any one of an oxygen atom, a nitrogen atom and a sulfur atom in the molecule, but a hydrocarbon composed of carbon and hydrogen is desirable.

  Examples of the phosphorus compound represented by the general formula (1) include phosphorous acid, monothiophosphorous acid, dithiophosphorous acid, trithiophosphorous acid; and a nitrous acid having one hydrocarbon group having 1 to 30 carbon atoms. Phosphoric acid monoester, monothiophosphorous acid monoester, dithiophosphorous acid monoester, trithiophosphorous acid monoester; phosphorous acid diester having two hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphorous acid diester , Dithiophosphite diester, trithiophosphite diester; phosphite triester having three hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphite triester, dithiophosphite triester, trithiophosphite And acid triesters; and mixtures thereof.

  Examples of the phosphorus compound represented by the general formula (2) include phosphoric acid, monothiophosphoric acid, dithiophosphoric acid, trithiophosphoric acid, tetrathiophosphoric acid; and phosphoric acid monoester having one hydrocarbon group having 1 to 30 carbon atoms. Monothiophosphoric acid monoester, dithiophosphoric acid monoester, trithiophosphoric acid monoester, tetrathiophosphoric acid monoester; phosphoric acid diester having two hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphoric acid diester, dithiophosphoric acid diester, trithiophosphoric acid Diesters, tetrathiophosphoric acid diesters; phosphoric acid triesters having three hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphoric acid triesters, dithiophosphoric acid triesters, trithiophosphoric acid triesters, tetrathiophosphoric acid triesters; 1-30 hydrocarbon groups ~ 3 phosphonic acid, phosphonic acid monoester, phosphonic acid diester; the above phosphorus compound having a (poly) oxyalkylene group having 1 to 4 carbon atoms; β-dithiophosphorylated propionic acid or dithiophosphoric acid and olefin cyclopentadiene or ( (Methyl) Derivatives of the above phosphorus compounds such as reaction products with methacrylic acid; and mixtures thereof.

  As the metal salt of the phosphorus compound represented by the general formula (1) or (2), the phosphorus compound may be a metal base such as a metal oxide, metal hydroxide, metal carbonate, metal chloride, ammonia, carbon number 1 Examples thereof include salts obtained by allowing a nitrogen compound such as an amine compound having only 30 hydrocarbon groups or hydroxyl group-containing hydrocarbon groups in the molecule to act to neutralize a part or all of the remaining acidic hydrogen.

  Specific examples of the metal in the metal base include alkali metals such as lithium, sodium, potassium and cesium, alkaline earth metals such as calcium, magnesium and barium, zinc, copper, iron, lead, nickel, silver and manganese. And heavy metals such as molybdenum. Among these, alkaline earth metals such as calcium and magnesium and zinc are preferable.

  Specific examples of the nitrogen-containing compound include nitrogen such as ammonia, an amine compound having a hydrocarbon group having 1 to 30 carbon atoms or a hydroxyl group-containing hydrocarbon group in the molecule, an amide bond-containing compound, and an imide bond-containing compound. Examples of the compound include the above-described component (C) and other ashless dispersants. Examples thereof include amine-based nitrogen-containing compounds such as monoamine, diamine, polyamine, and alkanolamine, nitrogen-containing compounds having an amide bond, and nitrogen-containing compounds having an imide bond. Among these nitrogen compounds, nitrogen-containing compounds having an alkyl group or alkenyl group having 10 to 20 carbon atoms such as decylamine, dodecylamine, dimethyldodecylamine, tridecylamine, heptadecylamine, octadecylamine, oleylamine and stearylamine (these are It may be linear or branched)).

As the component (D) of the present invention, the lubricating oil composition of the present invention contains, as a main component, at least one selected from the following (D1) and (D2) as the metal salt of the phosphorus-containing acid. Is particularly desirable.
(D1) zinc dialkyldithiophosphate (D2) a salt of a phosphorus-containing acid and a metal base having a sulfur content less than the component (D1) or containing no sulfur atom

  Examples of the component (D1) include those represented by the following general formula (3).

In the formula, R ¹ , R ² , R ³ and R ⁴ may be the same or different, and each of them is individually a secondary alkyl group or primary alkyl group having 1 to 30 carbon atoms, preferably 3 to 8 carbon atoms, preferably Represents a secondary alkyl group having 3 to 6 carbon atoms or a primary alkyl group having 6 to 8 carbon atoms, and has an alkyl group having a different carbon number and an alkyl group having different structure (secondary or primary) in the same molecule. You may do it.

  In the present invention, among the components (D1), it has a secondary alkyl group selected from 3 to 8 carbon atoms, more preferably a secondary alkyl group having 4 and / or 6 carbon atoms, from the viewpoint of superior wear prevention properties. It is preferable to contain zinc dialkyldithiophosphate, and zinc dialkyldithiophosphate having a primary alkyl group selected from 3 to 8 carbon atoms can be used in that oxidation stability can be further improved and base number maintenance performance can be improved. It is preferable to contain. These may be used in combination.

In addition, any conventional method can be adopted as a method for producing zinc dithiophosphate and is not particularly limited. Specifically, for example, an alkyl group corresponding to R ¹ , R ² , R ^3, and R ⁴ may be used. It can be synthesized by reacting the alcohol with diphosphorus pentasulfide to produce dithiophosphoric acid and neutralizing it with zinc oxide.

In the component (D2), all of X ^{1 to} X ³ in the general formula (1) are oxygen atoms (one or two of X ¹ , X ² and X ³ are single bonds or (poly) oxyalkylene groups). All of X ^{4 to} X ⁷ in the general formula (2) are oxygen atoms (one or two of X ⁴ , X ⁵ and X ⁶ are single bonds or (poly). A typical example is a metal salt of a phosphorus compound, which may be an oxyalkylene group. These components (D2) can be preferably used in that the long drain performance such as high temperature cleanliness, oxidation stability, and base number maintenance can be remarkably enhanced.

  The structure of the metal salt of the phosphorus compound varies depending on the valence of the metal and the number of OH groups of the phosphorus compound, and therefore the structure is not limited at all. For example, when 1 mol of zinc oxide and 2 mol of phosphoric acid diester (one OH group) are reacted, a compound having a structure represented by the following general formula (4) is considered to be obtained as a main component. It is thought that there are some molecules

  For example, when 1 mol of zinc oxide and 1 mol of phosphoric acid monoester (having two OH groups) are reacted, a compound having a structure represented by the following general formula (5) is considered to be obtained as a main component. However, polymerized molecules are also thought to exist.

  Among these (D2) components, a salt of phosphorous acid diester having two alkyl groups or aryl groups having 3 to 18 carbon atoms and zinc, one alkyl group or aryl group having 3 to 18 carbon atoms Salt of phosphoric acid monoester and zinc, diester of phosphoric acid having two alkyl groups or aryl groups having 3 to 18 carbon atoms and zinc, two alkyl groups or aryl groups having 1 to 18 carbon atoms A salt of phosphonic acid monoester and zinc is preferable. Among these, use of a phosphoric acid monoester and / or a phosphoric acid diester zinc salt having an alkyl group having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms, is excellent in a good balance in oil solubility, antiwear properties and economic efficiency. Particularly desirable in terms. These components can be arbitrarily blended in one kind or two or more kinds.

  The metal salt of the phosphorus-containing acid in the lubricating oil composition of the present invention, preferably the upper limit of at least one content selected from the above (D1) and (D2) is 0.2% by mass or less, preferably as phosphorus content 0.1% by mass or less, more preferably 0.08% by mass or less, particularly preferably 0.06% by mass or less, and the lower limit is 0.005% by mass as the amount of phosphorus in that it is easy to suppress wear. Or more, preferably 0.02% by mass or more, particularly preferably 0.04% by mass or more.

  The lubricating oil composition for an internal combustion engine of the present invention has the above-described configuration to provide a composition having excellent hydrolysis stability, excellent base number maintenance performance in the presence of moisture, and excellent high-temperature cleanliness. However, a known lubricating oil additive can be added for the purpose of further enhancing the performance or for the purpose of further imparting the performance required as a lubricating oil composition for an internal combustion engine. Examples of additives that can be added include ashless dispersants other than component (C), extreme pressure additives other than component (D), viscosity index improvers, friction modifiers, antioxidants, metal deactivators, and rust inhibitors. Agents, corrosion inhibitors, pour point depressants, rubber swelling agents, antifoaming agents, colorants and the like. These can be used alone or in combination of several kinds.

  Examples of the ashless dispersant other than the component (C) include nitrogen-containing compounds such as benzylamine and polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms in the molecule, Alternatively, derivatives or modified products thereof may be mentioned. The alkyl group or alkenyl group having 40 to 400 carbon atoms may be linear or branched. Specifically, preferred examples include olefin oligomers such as propylene, 1-butene and isobutylene, and ethylene and propylene. Examples include branched alkyl groups and branched alkenyl groups derived from co-oligomers. In the lubricating oil composition of the present invention, one or two or more compounds arbitrarily selected from these can be used in any amount, but the content is usually the total amount of the lubricating oil composition. It is 0.1-10 mass% on the basis, Preferably it is 1-6 mass%.

  As the extreme pressure additive other than the component (D), any compound usually used as an extreme pressure additive for lubricating oil can be used. For example, dithiocarbamates, sulfides, sulfurized olefins, sulfurized fats and oils. And sulfur compounds such as phosphoric acid, phosphoric acid esters, phosphorous acid, phosphorous acid esters and amine salts thereof, and metal salts of phosphorus-containing acids containing sulfur. In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these can be contained in any amount, and the content is usually 0.01 to based on the total amount of the lubricating oil composition. 5.0% by mass.

  As specific examples of the viscosity index improver, specifically, a so-called non-dispersion type viscosity index improver such as a copolymer of one or more monomers selected from various methacrylates or a hydrogenated product thereof, Or what is called a dispersion-type viscosity index improver etc. which copolymerized various methacrylic acid ester containing a nitrogen compound can be illustrated. Specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α-olefin copolymers (the α-olefin can be exemplified by propylene, 1-butene, 1-pentene, etc.) or hydrogen thereof. And polyisobutylene or a hydrogenated product thereof, a styrene-diene hydrogenated copolymer, a styrene-maleic anhydride ester copolymer, and a polyalkylstyrene. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be contained in any amount, but the low temperature viscosity characteristics and fatigue prevention performance are further improved. Non-dispersed or dispersed polymethacrylate is preferable, and non-dispersed polymethacrylate is particularly preferable.

  The weight average molecular weight (Mw) of the viscosity index improver used in the present invention is usually 10,000 to 1,000,000, but preferably 100,000 to 600,000 in view of excellent shear stability and a fuel saving effect. More preferably, it is 200,000 to 500,000. In addition, the content of the viscosity index improver in the lubricating oil composition of the present invention is 0.01 to 20% by mass, preferably 5 to 15% by mass.

  As the friction modifier, any compound usually used as a friction modifier for lubricating oils can be used, and specifically, an alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly 6 to 30 carbon atoms. Ashless friction modifiers having at least one linear alkyl group or linear alkenyl group in the molecule, such as amine friction modifiers, imide friction modifiers, amide friction modifiers, fatty acid friction modifiers, etc. Is mentioned.

  As the amine friction modifier, straight chain or branched, preferably linear aliphatic monoamine having 6 to 30 carbon atoms, preferably linear or branched, preferably straight chain having 6 to 30 carbon atoms. Aliphatic aliphatic alkanolamines, linear or branched, preferably linear aliphatic polyamines, or aliphatic amine friction modifiers such as alkylene oxide adducts of these aliphatic amines.

  Examples of the imide-based friction modifier include mono- and / or mono- and / or bicyclic hydrocarbon groups having 6 to 30 carbon atoms, preferably 8 to 18 carbon atoms, and preferably having 1 or 2 branched hydrocarbon groups. Or a succinimide modified compound obtained by reacting one or more selected from bissuccinimide, boric acid, (phosphorous) phosphoric acid, carboxylic acid having 1 to 20 carbon atoms, or a sulfur-containing compound with the succinimide, etc. Examples thereof include succinimide friction modifiers.

  Examples of the amide friction modifier include fatty acid amide friction modifiers such as amides of linear or branched, preferably linear fatty acids and ammonia, aliphatic monoamines or aliphatic polyamines having 7 to 31 carbon atoms. Etc. can be illustrated.

  Examples of the fatty acid friction modifier include linear or branched, preferably linear fatty acids having 7 to 31 carbon atoms, and fatty acids such as esters of the fatty acids with aliphatic monohydric alcohols or aliphatic polyhydric alcohols. Examples include esters, fatty acid metal salts such as alkaline earth metal salts (magnesium salts, calcium salts, etc.) and zinc salts of the fatty acids.

  In the present invention, one or two or more compounds arbitrarily selected from these friction modifiers can be contained in any proportion, but the content is usually based on the total amount of the lubricating oil composition. 0.01 to 5.0 mass%, preferably 0.03 to 3.0 mass%.

  As the antioxidant, any phenolic compound or amine compound that is generally used in lubricating oils can be used. Specifically, alkylphenols such as 2,6-di-tert-butyl-4-methylphenol and bisphenols such as methylene-4,4-bisphenol (2,6-di-tert-butyl-4-methylphenol) , Naphthylamines such as phenyl-α-naphthylamine, dialkyldiphenylamines, (3,5-di-tert-butyl-4-hydroxyphenyl) fatty acid (propionic acid etc.) and mono- or polyhydric alcohols such as methanol, Esters with octadecanol, 1,6 hexadiol, neopentyl glycol, thiodiethylene glycol, triethylene glycol, pentaerythritol, etc., organometallic antioxidants such as phenothiazines, molybdenum, copper and zinc, and mixtures thereof Can be mentioned. In the present invention, an amine-based antioxidant is particularly preferable in that it is excellent in high-temperature cleanability and can further enhance the base number maintenance performance in the presence of moisture. In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these can be contained in any amount, and the content is usually 0.01 to based on the total amount of the lubricating oil composition. 5.0% by mass.

  Examples of the metal deactivator include thiazole compounds and thiadiazole compounds, and thiadiazole compounds are preferably used. The thiadiazole compound includes 2,5-bis (alkylthio) -1,3,4-thiadiazole having 6 to 24 carbon atoms or a straight or branched alkyl group having 6 to 24 carbon atoms. 2,5-bis (alkyldithio) -1,3,4-thiadiazole having a group, 2- (alkylthio) -5-mercapto-1, having a linear or branched alkyl group having 6 to 24 carbon atoms, Examples include 3,4-thiadiazole, 2- (alkyldithio) -5-mercapto-1,3,4-thiadiazole having a linear or branched alkyl group having 6 to 24 carbon atoms, and a mixture thereof. Among these, 2,5-bis (alkyldithio) -1,3,4-thiadiazole is particularly preferable. The content of these metal deactivators is 0.005 to 0.5% by mass based on the total amount of the composition.

  Examples of the rust inhibitor include alkenyl succinic acid, alkenyl succinic acid ester, polyhydric alcohol ester, petroleum sulfonate, dinonyl naphthalene sulfonate and the like. Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, and imidazole compounds. Examples of the pour point depressant include polymethacrylate polymers that are compatible with the lubricating base oil used. Examples of rubber swelling agents include aromatic and ester rubber swelling agents. Examples of the antifoaming agent include silicones such as dimethyl silicone and fluorosilicone. The content of these additives is arbitrary, but the content of the corrosion inhibitor is usually 0.005 to 0.2% by mass and the content of the antifoaming agent is 0.0005 to 0.00 based on the total amount of the composition. The content of 01% by mass and other additives is about 0.005 to 10% by mass, respectively.

Kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention is usually 2 to 25 mm ² / s, preferably 4 to 15 mm ² / s, more preferably 5 to 10 mm ² / s, more preferably 6.5~8mm ² / s. The viscosity index of the lubricating oil composition of the present invention is usually 160 or higher, preferably 180 or higher, more preferably 200 or higher.

  The lubricating oil composition for an internal combustion engine of the present invention is very excellent in hydrolysis stability, and can maintain a high base number even under conditions where water is mixed and easily accumulates. Moreover, since the lubricating oil composition for internal combustion engines of the present invention has good high temperature cleanliness, it is possible to maintain engine performance and extend the life of the lubricating oil. Therefore, it can be suitably used for an internal combustion engine of a hybrid vehicle driven by an electric motor and / or an engine, particularly a parallel or series-parallel hybrid vehicle in which engine stop and operation are frequently repeated. It is also suitable for use in marine internal combustion engines such as outboard motors that are operated under conditions in which moisture does not easily evaporate, gas engines that are likely to contain a large amount of moisture, gasoline engines that have idling stop control, diesel engines, etc. be able to.

  The lubricating oil composition of the present invention can also be used for applications other than those for the internal combustion engine, for automatic transmissions such as automobiles, construction machines, and agricultural machines, for continuously variable transmissions, or for manual transmissions. Also, it can be suitably used for lubricating oil for differential gear, industrial gear oil, turbine oil, compressor oil, and the like.

  Hereinafter, the content of the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Table 1 shows the properties of the lubricating base oils 1 to 3 used in the examples of the present invention. Using these lubricating base oils, a total of 8 lubricating oil compositions of Sample Nos. 1 to 8 were prepared so as to have the compositions shown in Table 2. The ratio of the base oil is based on the total amount of the base oil, and the amount of each additive is based on the total amount of the composition. These lubricating oil compositions were evaluated for high-temperature cleanliness and hydrolysis stability by the following evaluation methods. The evaluation results are also shown in Table 2.
(1) Hydrolysis test Hydrolysis test was performed in accordance with ASTM D 2619, and base number (hydrochloric acid method) was measured for the test oil after hydrolysis test. Was measured, and the reduction rate of the base number relative to the base number of the new oil was determined.

(2) High temperature cleanliness seen in hot tube test A hot tube test was performed in accordance with JPI-5S-5599. The score was 10 points for colorless and transparent (no stain) and 0 point for black opaque, and the evaluation was made with reference to a standard tube prepared in advance by 1 interval. If the said score is 6.0 or more in 290 degreeC, it can be said that it is what was excellent in the cleanliness as a lubricating oil, and it can be said that the cleanliness is especially excellent in the thing whose score is 8.0 or more.

  As is apparent from Table 2, the lubricating oil compositions of Sample Nos. 1 to 5 according to the present invention have a very low base number reduction rate after the hydrolysis test while exhibiting high fresh oil high temperature cleanliness, It can be seen that the performance of the metallic detergent can be easily maintained for a long time even under mixing. In particular, the lubricating oil compositions of Sample Nos. 2 to 4, especially Sample Nos. 2 and 3, showed very excellent results in both the hydrolysis test and the high temperature cleanability test.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. In addition, the lubricating oil composition for an internal combustion engine accompanying such a change can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the lubricating oil composition for such an internal combustion engine is also included in the technical scope of the present invention. Must be understood as being.

Claims (4)

(A) To the lubricating base oil, based on the total amount of the composition,
(B1) 0.005 to 0.5% by mass of a salicylate detergent as a metal amount,
(C2) 0.005 to 0.4% by mass of (C) succinimide-based ashless dispersant comprising only succinimide-based ashless dispersant containing no boron as the amount of nitrogen,
(D) 0.005 to 0.2% by mass with a metal salt of a phosphorus-containing acid as the amount of phosphorus,
A lubricating oil composition for an internal combustion engine of a hybrid vehicle, comprising: (A) To the lubricating base oil, based on the total amount of the composition,
(B1) 0.005 to 0.5% by mass of a salicylate detergent as a metal amount,
(C1) 0.001 to 0.03% by mass of boron-containing succinimide ashless dispersant as the amount of boron,
(C2) 0.005 to 0.4 mass% of succinimide-based ashless dispersant containing no boron as the amount of nitrogen,
(D) 0.005 to 0.2% by mass with a metal salt of phosphorus-containing organic acid as the amount of phosphorus,
A lubricating oil composition for an internal combustion engine of a hybrid vehicle, comprising: The mass ratio (B / N ratio) of the total nitrogen content attributable to the (C1) component and the (C2) component and the boron content attributable to the (C1) component is 0.05 to 0.3. The lubricating oil composition for an internal combustion engine according to claim 2. 3. The internal combustion engine according to claim 1, wherein the component (B1) is a metal salt of an alkyl salicylic acid containing a dialkyl salicylic acid and / or a (over) basic salt thereof. Lubricating oil composition.