JP5695815B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition, and in particular, a lubricating oil composition, particularly an automatic transmission and / or a continuously variable transmission, having excellent fuel economy and low-temperature fluidity and excellent metal fatigue resistance. And a lubricating oil composition suitable for an internal combustion engine.

  Conventionally, lubricating oils used in automatic transmissions, manual transmissions, and internal combustion engines have viscosity temperature characteristics to improve various durability such as thermal oxidation stability, wear resistance, and fatigue resistance and to improve fuel efficiency. Improvement of low-temperature viscosity characteristics such as improvement of low temperature, reduction of low-temperature viscosity, improvement of low-temperature fluidity is required. In order to improve such performance, various additives such as antioxidants, detergent dispersants, antiwear agents, friction modifiers, seal swelling agents, viscosity index improvers, antifoaming agents, colorants, etc., are appropriately added to the base oil. Lubricating oil blended with an agent is used.

  Recent transmissions and engine oils are required to save fuel, be lighter, smaller, and have higher output. In addition, transmissions have been pursued to improve their power transmission capabilities as the combined output of engines increases. Yes. For this reason, the lubricating oil used in these products is required to maintain high lubrication performance and reduce wear and fatigue on the surfaces of bearings, gears, etc. while reducing product viscosity and base oil viscosity. . In addition, automatic transmissions and continuously variable transmissions are assumed to be used in cold regions of -10 ° C or lower, and further improvements in low-temperature performance are aimed at improving low-temperature startability and fuel consumption at low temperatures. It has been demanded.

  As a general technique for improving fuel economy, there is a technique for improving viscosity temperature characteristics by reducing the base oil viscosity and increasing the viscosity index improver. However, the fatigue resistance is deteriorated due to the reduction in the base oil viscosity. Further, the improvement of the low temperature viscosity characteristics can be achieved by reducing the base oil viscosity or the product viscosity, but if the base oil viscosity is reduced, the wear prevention property and the fatigue prevention property are deteriorated.

Therefore, methods to improve fuel economy, low temperature viscosity characteristics and fatigue life at the same time are being studied. Use of base oils with good low temperature performance, combined use of low and high viscosity base oils, phosphorus-based electrodes Techniques such as addition of appropriate amounts of pressure agents and sulfur-based extreme pressure agents have been proposed (for example, Patent Documents 1 to 3).
Japanese Patent Application Laid-Open No. 2004-262979 Japanese Patent Laid-Open No. 11-286696 Special table 2003-514099 gazette

  However, even with the above-described method, it is difficult to sufficiently improve both the viscosity-temperature characteristics, the low-temperature performance, and the metal fatigue life, and there is still room for improvement as it can be put to practical use.

  The present invention has been made in view of such circumstances, and has a lubricating oil composition, particularly an automatic transmission and / or a continuously variable transmission, having excellent viscosity-temperature characteristics and low-temperature performance, and having an excellent metal fatigue life. It is an object to provide a lubricating oil composition suitable for a machine.

  In order to solve the above problems, the present invention contains a mineral oil base oil having a urea adduct value of 4% by mass or less and a viscosity index of 100 or more, an ester base oil, and a viscosity index improver. A lubricating oil composition is provided.

  The mineral base oil contained in the lubricating oil composition of the present invention is excellent in thermal and oxidation stability because the urea adduct value and viscosity index satisfy the above conditions. Furthermore, when the additive is blended, the mineral oil-based base oil can exhibit its function at a higher level while stably dissolving and holding the additive. And, by using the mineral base oil having such excellent characteristics together with the ester base oil and the viscosity index improver, it is possible to achieve both low temperature viscosity characteristics and metal fatigue resistance, and as a result, sufficient savings can be achieved. It becomes possible to achieve fuel efficiency.

  Further, since the mineral base oil contained in the lubricating oil composition of the present invention satisfies the above conditions in terms of the urea adduct value and the viscosity index, it itself has excellent viscosity-temperature characteristics and friction characteristics. According to the mineral oil base oil, it is possible to reduce viscosity resistance and stirring resistance in a practical temperature range due to excellent viscosity-temperature characteristics. Since the effect can be exhibited by drastically reducing, energy loss in the apparatus can be reduced and energy saving can be achieved. Further, the mineral base oil is excellent in terms of solubility and effectiveness of the additive as described above, and when a friction modifier is blended, the friction reducing effect can be obtained at a high level. is there. Therefore, according to the lubricating oil composition of the present invention including such an excellent mineral oil base oil, energy loss due to frictional resistance, stirring resistance and the like in the sliding portion is reduced, and sufficient energy saving is achieved. be able to.

  Furthermore, in the case of conventional mineral base oils, it has been difficult to achieve both low temperature viscosity characteristics improvement and prevention of volatilization. However, according to the mineral oil base oil according to the present invention, low temperature viscosity characteristics and volatilization prevention can be achieved. Both can be achieved at a high level and in a well-balanced manner. Therefore, the lubricating oil composition of the present invention is useful not only for energy saving but also for improving startability at low temperatures.

  The urea adduct value as used in the present invention is measured by the following method. 100 g of weighed sample oil (lubricating base oil) is placed in a round bottom flask, 200 mg of urea, 360 ml of toluene and 40 ml of methanol are added and stirred at room temperature for 6 hours. As a result, white granular crystals are produced as urea adducts in the reaction solution. The reaction solution is filtered through a 1 micron filter to collect the produced white granular crystals, and the obtained crystals are washed 6 times with 50 ml of toluene. The collected white crystals are put into a flask, 300 ml of pure water and 300 ml of toluene are added, and the mixture is stirred at 80 ° C. for 1 hour. The aqueous phase is separated and removed with a separatory funnel, and the toluene phase is washed three times with 300 ml of pure water. A desiccant (sodium sulfate) is added to the toluene phase for dehydration, and then toluene is distilled off. The ratio (mass percentage) of the urea adduct thus obtained to the sample oil is defined as the urea adduct value.

  Moreover, the viscosity index as used in the present invention and the kinematic viscosity at 40 ° C. or 100 ° C. described later mean the viscosity index measured according to JIS K 2283-1993 and the kinematic viscosity at 40 ° C. or 100 ° C., respectively. .

  In the meantime, as described above, improvement of the isomerization rate from normal paraffin to isoparaffin has been studied in the refining method of mineral oil base oil by hydrocracking / hydroisomerization as described above. According to the above study, it is difficult to sufficiently improve the low-temperature viscosity characteristics simply by reducing the residual amount of normal paraffin. That is, the isoparaffin produced by hydrocracking / hydroisomerization contains components that adversely affect the low-temperature viscosity characteristics, but this point is not fully recognized in conventional evaluation methods. Analytical methods such as gas chromatography (GC) and NMR are applied to the analysis of normal paraffin and isoparaffin. In these analytical methods, components that adversely affect the low-temperature viscosity characteristics are separated or specified from isoparaffin. This cannot be said to be practically effective because it requires complicated work and a lot of time.

  On the other hand, in the measurement of the urea adduct value in the present invention, as urea adduct, a component that adversely affects low-temperature viscosity characteristics among isoparaffins, and further, when normal paraffin remains in the mineral oil base oil Since the normal paraffin can be collected accurately and reliably, it is excellent as an evaluation index for the low-temperature viscosity characteristics of mineral oil base oils. In addition, as a result of analysis using GC and NMR, the present inventors have found that the main component of the urea adduct is normal paraffin and isoparaffin urea adduct having 6 or more carbon atoms from the end of the main chain to the branch position. It is confirmed that.

  In the present invention, the mineral oil-based base oil is hydrocracked so that the raw material oil containing normal paraffin has a urea adduct value of 4% by mass or less and a viscosity index of 100 or more. It is preferable that it was obtained by the process of performing hydroisomerization. As a result, it is possible to more reliably obtain a lubricating oil composition in which thermal / oxidation stability, viscosity-temperature characteristics, and low-temperature viscosity characteristics are compatible at a high level.

  In addition, the above-mentioned mineral base oil is a hydrocracking / hydroisomerization so that the raw material oil containing normal paraffin has a urea adduct value of 4% by mass or less and a viscosity index of 100 or more in the obtained product. In the case where the raw material oil is obtained by the step of converting, the raw material oil preferably contains 50% by mass or more of slack wax obtained by solvent dewaxing of the mineral oil base oil.

  As described above, according to the present invention, it is possible to realize a lubricating oil composition excellent in thermal / oxidation stability or further in viscosity-temperature characteristics / low temperature viscosity characteristics, metal fatigue prevention properties and volatilization prevention properties. Then, by applying the lubricating oil composition of the present invention to an automatic transmission and / or a continuously variable transmission, it becomes possible to achieve fuel saving.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The lubricating oil composition of the present invention comprises (A) a mineral oil base oil having a urea adduct value of 4% by mass or less and a viscosity index of 100 or more (hereinafter sometimes referred to as “mineral oil base oil according to the present invention”). "(A) component"), (B) ester base oil (hereinafter sometimes referred to as "(B) component"), and (C) viscosity index improver (hereinafter sometimes referred to as "(C)"). Component ").

  The urea adduct value of the mineral base oil according to the present invention is required to be 4% by mass or less as described above from the viewpoint of improving the low temperature viscosity characteristics without impairing the viscosity-temperature characteristics, and preferably 3. 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 2.5 mass% or less. Further, the urea adduct value of the mineral oil base oil may be 0% by mass. However, it is possible to obtain a mineral oil base oil having sufficient low-temperature viscosity characteristics and a higher viscosity index, and more preferably 0.1% by mass or more, in terms of excellent economic efficiency by relaxing dewaxing conditions. Preferably it is 0.5 mass% or more, Most preferably, it is 0.8 mass% or more.

  From the viewpoint of viscosity-temperature characteristics, the viscosity index of the mineral base oil according to the present invention needs to be 100 or more as described above, preferably 110 or more, more preferably 120 or more, and still more preferably 125 or more. Especially preferably, it is 130 or more.

  In producing the mineral base oil according to the present invention, a raw oil containing normal paraffin or a wax containing normal paraffin can be used. The raw material oil may be either mineral oil or synthetic oil, or a mixture of two or more of these.

  The raw material oil used in the present invention is preferably a wax-containing raw material that boils in the lubricating oil range specified in ASTM D86 or ASTM D2887. The wax content of the raw material oil is preferably 50% by mass or more and 100% by mass or less based on the total amount of the raw material oil. The wax content of the raw material can be measured by analytical techniques such as nuclear magnetic resonance spectroscopy (ASTM D5292), correlated ring analysis (ndM) method (ASTM D3238), solvent method (ASTM D3235) and the like.

  Examples of the wax-containing raw material include oils derived from solvent refining methods such as raffinate, partial solvent dewaxed oil, dewaxed oil, distillate, reduced pressure gas oil, coker gas oil, slack wax, foots oil, and fisher Tropsch wax and the like are mentioned, and among these, slack wax and Fischer-Tropsch wax are preferable.

  Slack waxes are typically derived from hydrocarbon feedstocks by solvent or propane dewaxing. Slack wax may contain residual oil, which can be removed by deoiling. Foots oil corresponds to deoiled slack wax.

  Fischer-Tropsch wax is produced by a so-called Fischer-Tropsch synthesis method.

  Furthermore, you may use a commercial item as raw material oil containing normal paraffin. Specific examples include Paraflint 80 (hydrogenated Fischer-Tropsch wax) and Shell MDS Waxy Raffinate (hydrogenated and partially isomerized middle distillate synthetic waxy raffinate). It is done.

  Moreover, the raw material oil derived from solvent extraction is obtained by sending a high-boiling petroleum fraction from atmospheric distillation to a vacuum distillation apparatus and solvent-extracting the distillation fraction from this apparatus. The residue from the vacuum distillation may be denitrified. In the solvent extraction method, aromatic components are dissolved in the extraction phase while leaving more paraffinic components in the raffinate phase. Naphthene is partitioned into the extraction phase and the raffinate phase. As the solvent for solvent extraction, phenol, furfural, N-methylpyrrolidone and the like are preferably used. By controlling the solvent / oil ratio, the extraction temperature, the method of contacting the distillate to be extracted with the solvent, etc., the degree of separation between the extraction phase and the raffinate phase can be controlled. Furthermore, a bottom fraction obtained from a fuel oil hydrocracking apparatus may be used as a raw material by using a fuel oil hydrocracking apparatus having higher hydrogenation resolution.

The raw material oil is subjected to hydrocracking / hydroisomerization so that the urea adduct value of the material to be treated is 4% by mass or less and the viscosity index is 100 or more. Such a mineral oil base oil can be obtained. The hydrocracking / hydroisomerization step is not particularly limited as long as the urea adduct value and the viscosity index of the obtained workpiece satisfy the above conditions. The preferred hydrocracking / hydroisomerization step in the present invention is:
A first step of hydrotreating a raw oil containing normal paraffin using a hydrotreating catalyst;
A second step of hydrodewaxing the object to be treated obtained in the first step using a hydrodewaxing catalyst;
The to-be-processed object obtained by a 2nd process is equipped with the 3rd process of hydrotreating using a hydrotreating catalyst.

  In the conventional hydrocracking / hydroisomerization, a hydrotreating step is provided before the hydrodewaxing step for the purpose of desulfurization / denitrogenation for the prevention of poisoning of the hydrodewaxing catalyst. There is a thing. On the other hand, in the first step (hydrotreating step) in the present invention, a part of the normal paraffin in the feedstock (for example, about 10% by mass, preferably in the previous stage of the second step (hydrodewaxing step), 1 to 10% by mass), and desulfurization / denitrogenation is possible in the first step, but the purpose is different from that of the conventional hydrotreatment. Providing such a first step is preferable in order to ensure that the urea adduct value of the workpiece (mineral oil base oil) obtained after the third step is 4% by mass or less.

  Examples of the hydrogenation catalyst used in the first step include a catalyst containing a Group 6 metal, a Group 8-10 metal, and a mixture thereof. Preferred metals include nickel, tungsten, molybdenum, cobalt, and mixtures thereof. The hydrogenation catalyst can be used in a form in which these metals are supported on a refractory metal oxide support, and the metal is usually present as an oxide or sulfide on the support. When a metal mixture is used, the metal may be present as a bulk metal catalyst in which the amount of metal is 30% by mass or more based on the total amount of the catalyst. Examples of the metal oxide support include oxides such as silica, alumina, silica-alumina, and titania, and among these, alumina is preferable. Preferred alumina is γ-type or β-type porous alumina. The amount of metal supported is preferably in the range of 0.5 to 35% by mass based on the total amount of the catalyst. Also, when using a mixture of Group 9-10 metal and Group 6 metal, either Group 9 or Group 10 metal is present in an amount of 0.1-5% by weight, based on the total amount of catalyst, The Group 6 metal is preferably present in an amount of 5 to 30% by mass. Metal loading may be measured by atomic absorption spectroscopy, inductively coupled plasma emission spectroscopy, or other methods specified by ASTM for individual metals.

  The acidity of the metal oxide support can be controlled by adding additives, controlling the nature of the metal oxide support (eg, controlling the amount of silica incorporated into the silica-alumina support), and the like. Examples of additives include halogens, especially fluorine, phosphorus, boron, yttria, alkali metals, alkaline earth metals, rare earth oxides, and magnesia. Cocatalysts such as halogen generally increase the acidity of the metal oxide support, but weakly basic additives such as yttria or magnesia tend to weaken the acidity of such support.

Regarding the hydrotreatment conditions, the treatment temperature is preferably 150 to 450 ° C., more preferably 200 to 400 ° C., the hydrogen partial pressure is preferably 1400 to 20000 kPa, more preferably 2800 to 14000 kPa, and the liquid space velocity (LHSV) is preferably 0.1 to 10 ^-1, more preferably 0.1～5Hr ^-1, a hydrogen / oil ratio is preferably 50~1780m ³ / ^{m 3,} more preferably 89～890M ³ / M ³ . In addition, said conditions are an example and the hydrotreating conditions in the 1st process for the urea adduct value and viscosity index of the to-be-processed object obtained after a 3rd process satisfy | fill said conditions respectively are a raw material, a catalyst, an apparatus, etc. It is preferable to select appropriately according to the difference.

  The object to be processed after the hydrogenation treatment in the first step may be used as it is in the second step, but the object to be processed is stripped or distilled to generate gas from the object to be processed (liquid product). It is preferable to provide a step of separating and removing the object between the first step and the second step. Thereby, the nitrogen content and the sulfur content contained in the workpiece can be reduced to a level without affecting the long-term use of the hydrodewaxing catalyst in the second step. The object of separation and removal by stripping or the like is mainly gaseous foreign matters such as hydrogen sulfide and ammonia, and stripping can be performed by ordinary means such as a flash drum and a fractionator.

  Moreover, when the conditions of the hydrogenation treatment in the first step are mild, there is a possibility that the remaining polycyclic aromatics may pass through depending on the raw materials used. It may be removed by purification.

  Further, the hydrodewaxing catalyst used in the second step may contain either crystalline or amorphous material. Examples of the crystalline material include molecular sieves having a 10- or 12-membered ring passage mainly composed of aluminosilicate (zeolite) or silicoaluminophosphate (SAPO). Specific examples of zeolite include ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, ferrierite, ITQ-13, MCM-68, MCM-71 and the like. Moreover, ECR-42 is mentioned as an example of an aluminophosphate. Examples of molecular sieves include zeolite beta and MCM-68. Among these, it is preferable to use 1 type, or 2 or more types selected from ZSM-48, ZSM-22, and ZSM-23, and ZSM-48 is particularly preferable. The molecular sieve is preferably in the hydrogen form. Although the reduction of the hydrodewaxing catalyst can occur in situ at the time of hydrodewaxing, a hydrodewaxing catalyst that has been subjected to a reduction treatment in advance may be subjected to hydrodewaxing.

  Examples of the amorphous material of the hydrodewaxing catalyst include alumina doped with a group 3 metal, fluorided alumina, silica-alumina, fluorided silica-alumina, silica-alumina, and the like.

  Preferred embodiments of the dewaxing catalyst include those equipped with bifunctional, ie, metal hydrogenation components that are at least one Group 6 metal, at least one Group 8-10 metal, or mixtures thereof. Preferred metals are group 9-10 noble metals such as Pt, Pd or mixtures thereof. The mounting amount of these metals is preferably 0.1 to 30% by mass based on the total amount of the catalyst. Examples of the catalyst preparation and the metal mounting method include an ion exchange method and an impregnation method using a decomposable metal salt.

  When molecular sieves are used, they may be combined with a binder material having heat resistance under hydrodewaxing conditions, or may be without a binder (self-bonding). As binder materials, silica, alumina, silica-alumina, combinations of two components of silica and other metal oxides such as titania, magnesia, tria, zirconia, silica-alumina-tria, silica-alumina-magnesia, etc. Inorganic oxides such as a combination of three components of oxides such as The amount of the molecular sieve in the hydrodewaxing catalyst is preferably 10 to 100% by mass, more preferably 35 to 100% by mass, based on the total amount of the catalyst. The hydrodewaxing catalyst is formed by a method such as spray drying or extrusion. The hydrodewaxing catalyst can be used in a sulfided or non-sulfided form, and a sulfided form is preferred.

Regarding hydrodewaxing conditions, the temperature is preferably 250-400 ° C., more preferably 275-350 ° C., and the hydrogen partial pressure is preferably 791-20786 kPa (100-3000 psig), more preferably 1480-17339 kPa (200- a 2500 psig), liquid hourly space velocity is preferably 0.1 to 10 ^-1, more preferably 0.1~5hr ^-1, a hydrogen / oil ratio is preferably 45~1780m ³ / ^{m 3} (250~10000scf / B), more preferably ^{89~890m 3 / m 3 (500~5000scf /} B). In addition, said conditions are an example and the hydrodewaxing conditions in the 2nd process for the urea adduct value and viscosity index of the to-be-processed object obtained after a 3rd process satisfy | fill the said conditions are a raw material, a catalyst, and an apparatus, respectively. It is preferable to select appropriately according to the difference.

  The object to be treated that has been hydrodewaxed in the second step is subjected to hydrorefining in the third step. Hydrorefining is a form of mild hydrotreating that aims to saturate olefins and residual aromatic compounds by hydrogenation in addition to removal of residual heteroatoms and hues. The hydrorefining in the third step can be carried out in cascade with the dewaxing step.

  The hydrorefining catalyst used in the third step is preferably a catalyst obtained by supporting a Group 6 metal, a Group 8-10 metal or a mixture thereof on a metal oxide support. Preferred metals include noble metals, especially platinum, palladium and mixtures thereof. If a mixture of metals is used, it may be present as a bulk metal catalyst where the amount of metal is 30% by weight or more based on the catalyst. The metal content of the catalyst is preferably 20% by mass or less for non-noble metals and 1% by mass or less for noble metals. The metal oxide support may be either amorphous or crystalline oxide. Specific examples include low acid oxides such as silica, alumina, silica-alumina or titania, and alumina is preferred. From the viewpoint of saturation of the aromatic compound, it is preferable to use a hydrorefining catalyst in which a metal having a relatively strong hydrogenation function is supported on a porous support.

  Preferred hydrorefining catalysts include mesoporous materials belonging to the M41S class or family of catalysts. M41S series catalysts are mesoporous materials with high silica content, and specifically include MCM-41, MCM-48 and MCM-50. Such a hydrorefining catalyst has a pore diameter of 15 to 100 mm, and MCM-41 is particularly preferable. MCM-41 is an inorganic porous non-layered phase having a hexagonal arrangement of uniformly sized pores. The physical structure of MCM-41 is like a bundle of straws where the opening of the straw (cell diameter of the pores) is in the range of 15-100 angstroms. MCM-48 has cubic symmetry, and MCM-50 has a layered structure. MCM-41 can be manufactured with pore openings of different sizes in the mesoporous range. The mesoporous material may have a metal hydrogenation component that is at least one of Group 8, Group 9 or Group 10 metal, and the metal hydrogenation component is preferably a noble metal, particularly a Group 10 noble metal, Pt , Pd or mixtures thereof are most preferred.

Regarding the hydrorefining conditions, the temperature is preferably 150-350 ° C, more preferably 180-250 ° C, the total pressure is preferably 2859-20786 kPa (about 400-3000 psig), and the liquid space velocity is preferably 0. 0.1 to 5 hr ⁻¹ , more preferably 0.5 to ³ hr ⁻¹ , and the hydrogen / oil ratio is preferably 44.5 to 1780 m ³ / m ³ (250 to 10,000 scf / B). The above conditions are only examples, and the hydrogenation conditions in the third step for satisfying the above conditions for the urea adduct value and the viscosity index of the object to be processed obtained after the third step are the differences in raw materials and processing equipment. It is preferable to select appropriately according to.

  Moreover, about the to-be-processed object obtained after a 3rd process, you may separate and remove a predetermined component by distillation etc. as needed.

  In the mineral base oil according to the present invention obtained by the above production method, the other properties are not particularly limited as long as the urea adduct value and the viscosity index satisfy the above conditions, respectively, but the mineral base oil according to the present invention is It is preferable that the following conditions are further satisfied.

  The content of the saturated component in the mineral base oil according to the present invention is preferably 90% by mass or more, more preferably 93% by mass or more, and still more preferably 95% by mass or more, based on the total amount of the mineral oil base oil. Moreover, the ratio of the cyclic | annular saturated part to the said saturated part becomes like this. Preferably it is 0.1-50 mass%, More preferably, it is 0.5-40 mass%, More preferably, it is 1-30 mass%, Most preferably, it is 5-20. % By mass. When the content of the saturated component and the ratio of the cyclic saturated component in the saturated component satisfy the above conditions, viscosity-temperature characteristics and thermal / oxidative stability can be achieved. When the additive is blended, the function of the additive can be expressed at a higher level while the additive is sufficiently stably dissolved and held in the mineral oil base oil. Furthermore, when the content of the saturated component and the ratio of the cyclic saturated component in the saturated component satisfy the above conditions, the friction characteristics of the mineral oil base oil itself can be improved, and as a result, the friction reducing effect is improved. As a result, energy saving can be improved.

  In addition, when content of a saturated part is less than 90 mass%, it exists in the tendency for a viscosity-temperature characteristic, thermal / oxidation stability, and a friction characteristic to become inadequate. Further, when the ratio of the cyclic saturated component to the saturated component is less than 0.1% by mass, when the additive is added to the mineral oil base oil, the solubility of the additive becomes insufficient, and the mineral oil base Since the effective amount of the additive dissolved and retained in the oil is reduced, the function of the additive tends to be unable to be obtained effectively. Furthermore, when the ratio of the cyclic saturated component in the saturated component exceeds 50% by mass, the effectiveness of the additive tends to decrease when the additive is blended with the mineral oil base oil.

  In the present invention, the ratio of the cyclic saturated component in the saturated component being 0.1 to 50% by mass is equivalent to the non-cyclic saturated component in the saturated component being 99.9 to 50% by mass. Here, the acyclic saturated component includes both normal paraffin and isoparaffin. The ratio of normal paraffin and isoparaffin in the mineral base oil according to the present invention is not particularly limited as long as the urea adduct value satisfies the above conditions, but the ratio of isoparaffin is preferably 50 to 99 based on the total amount of mineral oil base oil. 9.9% by mass, more preferably 60 to 99.9% by mass, still more preferably 70 to 99.9% by mass, and particularly preferably 80 to 99.9% by mass. When the ratio of isoparaffin in the mineral base oil satisfies the above conditions, viscosity-temperature characteristics and thermal / oxidative stability can be further improved, and when an additive is added to the mineral base oil Therefore, the function of the additive can be expressed at a higher level while the additive is sufficiently stably dissolved and held.

  In addition, content of the saturated part said by this invention means the value (unit: mass%) measured based on ASTM D 2007-93.

  In addition, the ratio of the cyclic saturated component and the non-cyclic saturated component in the saturated component referred to in the present invention is a naphthene component measured according to ASTM D 2786-91, respectively (measuring object: 1 ring to 6 ring naphthene, unit : Mass%) and alkane content (unit: mass%).

In addition, the ratio of normal paraffin in the mineral oil base oil referred to in the present invention is the gas chromatographic analysis of the saturated fraction separated and fractionated by the method described in ASTM D 2007-93 under the following conditions. This is a value obtained by converting the measured value when the ratio of normal paraffin in the saturated content is identified and quantified, based on the total amount of mineral oil base oil. In the identification and quantification, a normal paraffin mixed sample having 5 to 50 carbon atoms is used as a standard sample, and the normal paraffin occupying the saturated component is the total peak area value of the chromatogram (the peak derived from the diluent). Is obtained as a ratio of the sum of peak area values corresponding to each normal paraffin.
(Gas chromatography conditions)
Column: liquid phase nonpolar column (length 25 mm, inner diameter 0.3 mmφ, liquid phase film thickness 0.1 μm) Temperature rising condition: 50 ° C. to 400 ° C. (temperature rising rate: 10 ° C./min)
Carrier gas: helium (linear velocity: 40 cm / min)
Split ratio: 90/1
Sample injection amount: 0.5 μL (injection amount of sample diluted 20 times with carbon disulfide)

  Further, the ratio of isoparaffin in the mineral oil base oil means a value obtained by converting the difference between the acyclic saturated content in the saturated content and the normal paraffin in the saturated content, based on the total amount of the mineral oil base oil. .

  In the method of separating saturated components, or in analyzing the composition of cyclic saturated components, non-cyclic saturated components, etc., a similar method can be used in which similar results can be obtained. For example, in addition to the above, a method described in ASTM D 2425-93, a method described in ASTM D 2549-91, a method using high performance liquid chromatography (HPLC), a method obtained by improving these methods, and the like can be given.

  In addition, in the mineral oil base oil according to the present invention, when a bottom fraction obtained from a fuel oil hydrocracking apparatus is used as a raw material, the content of the saturated component is 90% by mass or more and occupies the saturated component. The proportion of the cyclic saturated component is 30 to 50% by mass, the proportion of the non-cyclic saturated component in the saturated component is 50 to 70% by mass, the proportion of isoparaffin in the mineral oil base oil is 40 to 70% by mass, and the viscosity index is A base oil of 100 to 135, preferably 120 to 130 can be obtained. When the urea adduct value satisfies the above conditions, the effect of the present invention, in particular, the MRV viscosity at −40 ° C. is 20000 mPa · s or less, particularly 10000 mPa · s. A lubricating oil composition having the following excellent low-temperature viscosity characteristics can be obtained. Further, in the mineral base oil according to the present invention, when slack wax or Fischer-Tropsch wax, which is a raw material having a high wax content (for example, a normal paraffin content of 50% by mass or more) is used as a raw material, The content of min is 90% by mass or more, the proportion of cyclic saturated component in the saturated component is 0.1 to 40% by mass, the proportion of non-cyclic saturated component in the saturated component is 60 to 99.9% by mass, A base oil having a ratio of isoparaffin in the mineral base oil of 60 to 99.9% by mass and a viscosity index of 100 to 170, preferably 135 to 160 is obtained. The effect of the invention, in particular, the MRV viscosity at −40 ° C. is 12000 mPa · s or less, particularly 7000 mPa · s or less, and has a very excellent characteristic in high viscosity index and low temperature viscosity characteristics. It is possible to obtain a lubricating oil composition.

  In addition, the aromatic content in the mineral base oil according to the present invention is preferably 5% by mass or less, more preferably 0.05 to 3% by mass, and still more preferably 0.1 to 0.1% by mass based on the total amount of the mineral oil base oil. 1% by mass, particularly preferably 0.1 to 0.5% by mass. If the aromatic content exceeds the above upper limit, viscosity-temperature characteristics, thermal / oxidative stability, friction characteristics, volatilization prevention characteristics, and low-temperature viscosity characteristics tend to decrease. When an additive is blended with the additive, the effectiveness of the additive tends to decrease. Further, the mineral oil base oil according to the present invention may not contain an aromatic component, but by making the content of the aromatic component 0.05% by mass or more, the solubility of the additive is further increased. Can be increased.

  In addition, content of an aromatic content here means the value measured based on ASTM D 2007-93. In general, the aromatic component includes alkylbenzene, alkylnaphthalene, anthracene, phenanthrene and alkylated products thereof, as well as compounds in which four or more benzene rings are condensed, pyridines, quinolines, phenols and naphthols. Aromatic compounds having atoms are included.

Moreover,% _{C p} of mineral base oil according to the present invention is preferably 80 or more, more preferably 82 to 99, more preferably 85 to 98, particularly preferably 90 to 97. When the% C _p of the mineral base oil is less than 80, the viscosity-temperature characteristics, thermal / oxidative stability and friction characteristics tend to be reduced, and when the additive is added to the mineral base oil The effectiveness of the additive tends to decrease. In addition, when% C _p of mineral base oil exceeds 99, the additive solubility will tend to be lower.

Moreover,% _{C N} of the mineral base oil used in the present invention is preferably 20 or less, more preferably 15 or less, more preferably 1 to 12, more preferably 3 to 10. If the% C _N value of the mineral base oil exceeds 20, the viscosity - temperature characteristic, thermal and oxidation stability and frictional properties will tend to be reduced. Moreover, when% _CN is less than 1, the solubility of the additive tends to decrease.

Moreover,% _{C A} of the mineral base oil used in the present invention is preferably 0.7 or less, more preferably 0.6 or less, more preferably 0.1 to 0.5. If the% C _A value of the mineral base oil exceeds 0.7, the viscosity - temperature characteristic, thermal and oxidation stability and frictional properties will tend to be reduced. Moreover,% C _A of the mineral base oil used in the present invention may be 0% by 0.1 or more C _A, it is possible to further increase the solubility of additives.

Furthermore, the ratio of the mineral base% in oil _{C P} and% _{C N} of the present _invention,% C is preferably P /% _{C N} is 7 or more, more preferably 7.5 or more, More preferably, it is 8 or more. When% C _P /% _CN is less than 7, viscosity-temperature characteristics, thermal / oxidative stability and friction characteristics tend to be reduced, and further, when an additive is blended in mineral oil base oil The effectiveness of the additive tends to decrease. _{Moreover,% C} P /% C _N is preferably 200 or less, more preferably 100 or less, more preferably 50 or less, particularly preferably 25 or less. By setting% C _P /% _CN to 200 or less, the solubility of the additive can be further increased.

Incidentally, _say% C P in the present invention,% _C A _N and% _{C A,} obtained by a method in accordance with ASTM D 3238-85, respectively (n-d-M ring analysis), the total carbon number of the paraffin carbon number The percentage of the total number of naphthene carbons to the total number of carbons, and the percentage of aromatic carbons to the total number of carbons. That is, the preferable ranges of% C _P ,% C _N and% C _A described above are based on the values obtained by the above method. For example, even a mineral base oil containing no naphthene is obtained by the above method. is% C _N may indicate a value greater than zero.

  Further, the iodine value of the mineral base oil according to the present invention is preferably 0.5 or less, more preferably 0.3 or less, still more preferably 0.15 or less, and less than 0.01. However, it is preferably 0.001 or more, and more preferably 0.05 or more, from the viewpoint of a small effect corresponding to that and economic efficiency. By setting the iodine value of the mineral base oil to 0.5 or less, the thermal and oxidation stability can be dramatically improved. In addition, the iodine value as used in the field of this invention means the iodine value measured by the indicator titration method of JISK0070 "the acid value of a chemical product, the saponification value, the iodine value, the hydroxyl value, and the unsaponification value."

  Further, the sulfur content in the mineral oil base oil according to the present invention depends on the sulfur content of the raw material. For example, when using a raw material that does not substantially contain sulfur, such as a synthetic wax component obtained by a Fischer-Tropsch reaction or the like, a mineral oil base oil that does not substantially contain sulfur can be obtained. In addition, when using raw materials containing sulfur such as slack wax obtained in the refining process of mineral oil base oil and micro wax obtained in the refined wax process, the sulfur content in the obtained mineral oil base oil is usually 100 mass ppm. That's it. In the mineral base oil according to the present invention, the content of sulfur content is preferably 10 mass ppm or less, from the viewpoint of further improving thermal and oxidation stability and reducing sulfur, and is 5 mass ppm or less. More preferred is 3 ppm by mass or less.

  Further, from the viewpoint of cost reduction, it is preferable to use slack wax or the like as a raw material. In that case, the sulfur content in the resulting mineral oil base oil is preferably 50 ppm by mass or less, and preferably 10 ppm by mass or less. More preferred. In addition, the sulfur content as used in the field of this invention means the sulfur content measured based on JISK2541-1996.

  The nitrogen content in the mineral oil base oil according to the present invention is not particularly limited, but is preferably 5 ppm by mass or less, more preferably 3 ppm by mass or less, and further preferably 1 ppm by mass or less. If the nitrogen content exceeds 5 ppm by mass, the thermal and oxidation stability tends to decrease. In addition, the nitrogen content as used in the field of this invention means the nitrogen content measured based on JISK2609-1990.

Moreover, as for the kinematic viscosity of the mineral base oil according to the present invention, the kinematic viscosity at 100 ° C. is preferably 1.5 to ²⁰ mm ² / s, more preferably 2.0 to 11 mm ² / s. When the kinematic viscosity at 100 ° C. of the mineral oil base oil is less than 1.5 mm ² / s, it is not preferable in terms of evaporation loss. Moreover, when trying to obtain a mineral base oil having a kinematic viscosity at 100 ° C. exceeding 20 mm ² / s, the yield is lowered, and the decomposition rate is increased even when heavy wax is used as a raw material. Since it becomes difficult, it is not preferable.

In the present invention, it is preferable to use a mineral oil base oil having a kinematic viscosity at 100 ° C. in the following range by distillation or the like.
(I) less than the kinematic viscosity at 100 ° C. is 1.5 mm ² / s or more 3.5 mm ² / s, more preferably 2.0 to 3.0 mm ² / s mineral base oils (II) a kinematic viscosity at 100 ° C. There 3.0 mm ² / s or more 4.5mm less than ² / s, more preferably a kinematic viscosity at 3.5~4.1mm ² / s mineral base oils (III) 100 ℃ 4.5~20mm ² / s, more preferably 4.8 to 11 mm ² / s, particularly preferably 5.5 to 8.0 mm ² / s.

Moreover, the kinematic viscosity at 40 ° C. of the mineral oil base oil according to the present invention is preferably 6.0 to 80 mm ² / s, more preferably 8.0 to 50 mm ² / s. In the present invention, it is preferred that a lubricating oil fraction having a kinematic viscosity at 40 ° C. in the following range is fractionated by distillation or the like and used.
(IV) below 40 kinematic viscosity at ° C. is 6.0 mm ² / s or more 12 mm ² / s, more preferably kinematic viscosity at 8.0~12mm ² / s mineral base oil (V) 40 ° C. is 12 mm ² / s or more 28mm less than ² / s, more preferably 13~19mm ² / s mineral base oils (VI) 40 kinematic viscosity at ℃ is 28～50Mm ² / s, more preferably 29~45mm ² / s, particularly preferably Is a mineral base oil of 30-40 mm ² / s.

  The mineral base oils (I) and (IV) have a viscosity-temperature characteristic and a low temperature compared with the conventional mineral base oils having the same viscosity grade because the urea adduct value and the viscosity index satisfy the above conditions, respectively. Viscosity characteristics can be achieved at a high level, in particular, low temperature viscosity characteristics are excellent, and viscosity resistance and stirring resistance can be significantly reduced. Moreover, the BF viscosity in -40 degreeC can be 2000 mPa * s or less by mix | blending a pour point depressant. The BF viscosity at −40 ° C. means the viscosity measured according to JPI-5S-26-99.

  Further, the mineral base oils (II) and (V) have viscosity-temperature characteristics compared to the conventional mineral base oils having the same viscosity grade because the urea adduct value and the viscosity index satisfy the above conditions. And low-temperature viscosity characteristics can be achieved at a high level. In particular, the low-temperature viscosity characteristics are excellent, and further, volatilization prevention and lubricity are excellent. For example, in the mineral oil base oils (II) and (V), the CCS viscosity at −35 ° C. can be set to 3000 mPa · s or less.

  In addition, the mineral base oils (III) and (VI) have viscosity-temperature characteristics compared to conventional mineral base oils having the same viscosity grade by satisfying the above conditions for the urea adduct value and the viscosity index, respectively. And low-temperature viscosity characteristics can be achieved at a high level, in particular, excellent low-temperature viscosity characteristics, and further excellent volatilization prevention, thermal / oxidative stability, and lubricity.

  Further, the refractive index at 20 ° C. of the mineral base oil according to the present invention depends on the viscosity grade of the mineral base oil, but for example, the refractive index at 20 ° C. of the mineral base oils (I) and (IV). Is preferably 1.455 or less, more preferably 1.453 or less, and still more preferably 1.451 or less. Moreover, the refractive index at 20 ° C. of the mineral oil base oils (II) and (V) is preferably 1.460 or less, more preferably 1.457 or less, and further preferably 1.455 or less. The refractive index at 20 ° C. of the mineral oil base oils (III) and (VI) is preferably 1.465 or less, more preferably 1.463 or less, and further preferably 1.460 or less. When the refractive index exceeds the above upper limit, the viscosity-temperature characteristics and thermal / oxidative stability of the mineral oil base oil tend to be reduced, and further, the volatilization prevention property and low-temperature viscosity characteristics tend to deteriorate. When an additive is blended with the additive, the effectiveness of the additive tends to decrease.

  Further, the pour point of the mineral base oil according to the present invention depends on the viscosity grade of the mineral base oil. For example, the pour point of the mineral base oils (I) and (IV) is preferably −10. ° C or lower, more preferably -12.5 ° C or lower, still more preferably -15 ° C or lower. The pour point of the mineral oil base oils (II) and (V) is preferably −10 ° C. or lower, more preferably −15 ° C. or lower, and further preferably −17.5 ° C. or lower. The pour point of the mineral oil base oils (III) and (VI) is preferably −10 ° C. or lower, more preferably −12.5 ° C. or lower, and further preferably −15 ° C. or lower. When the pour point exceeds the upper limit, the low temperature fluidity of the entire lubricating oil using the mineral oil base oil tends to be lowered. In addition, the pour point as used in the field of this invention means the pour point measured based on JISK2269-1987.

  Moreover, although the CCS viscosity at -35 ° C of the mineral base oil according to the present invention depends on the viscosity grade of the mineral base oil, for example, the mineral base oils (I) and (IV) at -35 ° C are described above. The CCS viscosity is preferably 1000 mPa · s or less. The CCS viscosity at −35 ° C. of the mineral base oils (II) and (V) is preferably 3000 mPa · s or less, more preferably 2400 mPa · s or less, still more preferably 2000 mPa · s or less, and further preferably 1800 mPas. · S or less, particularly preferably 1600 mPa · s or less. Moreover, the CCS viscosity at −35 ° C. of the mineral oil base oils (III) and (VI) is preferably 15000 mPa · s or less, more preferably 10000 mPa · s or less. When the CCS viscosity at −35 ° C. exceeds the upper limit, the low-temperature fluidity of the entire lubricating oil using the mineral oil base oil tends to decrease. In addition, the CCS viscosity at −35 ° C. in the present invention means a viscosity measured according to JIS K 2010-1993.

  In addition, the Brukfield (BF) viscosity at −40 ° C. of the mineral oil base oil according to the present invention depends on the viscosity grade of the mineral oil base oil. For example, the mineral base oils (I) and (IV) The BF viscosity at −40 ° C. is preferably 10,000 mPa · s or less, more preferably 8000 mPa · s, and still more preferably 6000 mPa · s or less. Moreover, the BF viscosity at −40 ° C. of the mineral oil base oils (II) and (V) is preferably 1500,000 mPa · s or less, more preferably 1000000 mPa · s or less. When the BF viscosity at −40 ° C. exceeds the upper limit, the low-temperature fluidity of the entire lubricating oil using the mineral oil base oil tends to decrease.

  In addition, the brook field viscosity in -40 degreeC said by this invention means the value measured based on JPI-5S-26-99.

Further, the density (ρ ₁₅ ) at 15 ° C. of the mineral base oil according to the present invention depends on the viscosity grade of the mineral oil base oil, but is not more than the value of ρ represented by the following formula (1), that is, ρ It is preferable that ₁₅ ≦ ρ.
ρ = 0.0025 × kv100 + 0.816 (1)
[Wherein, kv100 represents the kinematic viscosity (mm ² / s) at 100 ° C. of the mineral oil base oil. ]

When ρ ₁₅ > ρ, viscosity-temperature characteristics and thermal / oxidation stability, volatilization prevention properties and low-temperature viscosity characteristics tend to decrease, and additives are added to mineral oil base oils. In some cases, the effectiveness of the additive tends to decrease.

For example, ρ ₁₅ of the mineral oil base oils (I) and (IV) is preferably 0.825 or less, more preferably 0.820 or less. Moreover, ρ ₁₅ of the mineral base oils (II) and (V) is preferably 0.835 or less, more preferably 0.830 or less. Moreover, ρ ₁₅ of the mineral base oils (III) and (VI) is preferably 0.840 or less, more preferably 0.835 or less.

  In addition, the density in 15 degreeC said by this invention means the density measured in 15 degreeC based on JISK2249-1995.

The aniline point (AP (° C.)) of the mineral base oil according to the present invention depends on the viscosity grade of the mineral oil base oil, but is not less than the value of A represented by the following formula (2), that is, AP It is preferable that ≧ A.
A = 4.3 × kv100 + 100 (2)
[Wherein, kv100 represents the kinematic viscosity (mm ² / s) at 100 ° C. of the mineral oil base oil. ]

  When AP <A, viscosity-temperature characteristics and thermal / oxidative stability, volatilization prevention properties and low-temperature viscosity characteristics tend to decrease, and additives are added to mineral base oils In addition, the effectiveness of the additive tends to decrease.

  For example, the AP of the mineral oil base oils (I) and (IV) is preferably 108 ° C or higher, more preferably 110 ° C or higher. The AP of the mineral oil base oils (II) and (V) is preferably 113 ° C or higher, more preferably 119 ° C or higher. The AP of the mineral oil base oils (III) and (VI) is preferably 125 ° C. or higher, more preferably 128 ° C. or higher. In addition, the aniline point as used in the field of this invention means the aniline point measured based on JISK2256-1985.

  Further, the NOACK evaporation amount of the mineral oil base oil according to the present invention is not particularly limited. For example, the NOACK evaporation amount of the mineral oil base oils (I) and (IV) is preferably 20% by mass or more, more preferably. Is 25% by mass or more, more preferably 30 or more, preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less. Further, the NOACK evaporation amount of the mineral oil base oils (II) and (V) is preferably 5% by mass or more, more preferably 8% by mass or more, still more preferably 10% by mass or more, and preferably 20%. It is at most mass%, more preferably at most 16 mass%, still more preferably at most 15 mass%. The NOACK evaporation amount of the mineral base oils (III) and (VI) is preferably 0% by mass or more, more preferably 1% by mass or more, and preferably 6% by mass or less, more preferably 5% by mass. It is at most 4% by mass, more preferably at most 4% by mass. When the NOACK evaporation amount is the lower limit value, it tends to be difficult to improve the low temperature viscosity characteristics. Further, when the NOACK evaporation amount exceeds the upper limit, when the mineral oil base oil is used for the lubricating oil for the internal combustion engine, the evaporation loss amount of the lubricating oil increases, and the catalyst poisoning is promoted accordingly. Therefore, it is not preferable. 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.

  The mineral base oil according to the present invention having the above structure is excellent in viscosity-temperature characteristics and low-temperature viscosity characteristics, has low viscosity resistance and stirring resistance, and further has improved thermal / oxidation stability and friction characteristics. Yes, it is possible to improve the friction reducing effect, and thus improve the energy saving property. In addition, when an additive is added to the mineral base oil according to the present invention, the function of the additive (the effect of improving the low temperature viscosity characteristics by the pour point depressant, the effect of improving the heat / oxidation stability by the antioxidant, the friction The friction reducing effect by the adjusting agent and the wear resistance improving effect by the antiwear agent can be expressed at a higher level. Therefore, the present invention is a lubricating oil (oil for a drive transmission device) mainly used for a drive transmission device such as an automatic transmission, a manual transmission, a continuously variable transmission, and a final reduction gear. Hydraulic oil, compressor oil, turbine oil, industrial gear oil, refrigerating machine oil, rust preventive oil, heat medium oil, gas holder seal oil, bearing oil, paper machine used in hydraulic equipment such as oil, shock absorbers and construction machinery It can also be suitably used for industrial oils, machine tool oils, sliding guide surface oils, electrical insulating oils, cutting oils, press oils, rolling oils, heat treatment oils, and the like.

  In the lubricating oil composition of the present invention, the mineral base oil according to the present invention may be used alone, and the mineral base oil according to the present invention is used as one or more of other mineral base oils. You may use together. In addition, when using together mineral oil base oil which concerns on this invention, and other mineral oil base oil, the ratio of the mineral oil base oil which concerns on this invention in those mixed base oils is 30 mass% or more Is more preferable, it is more preferable that it is 50 mass% or more, and it is still more preferable that it is 70 mass% or more.

The other mineral oil base oil used in combination with the mineral oil base oil according to the present invention is not particularly limited. For example, a solvent refined mineral oil, hydrocracked mineral oil having a kinematic viscosity at 100 ° C. of 1 to 100 mm ² / s, hydrogen Chemical refined mineral oil, solvent dewaxing base oil and the like.

  The lubricating oil composition of the present invention contains an ester base oil.

  The alcohol constituting the ester base oil may be a monohydric alcohol or a polyhydric alcohol, and the acid constituting the ester base oil may be a monobasic acid or a polybasic acid. The ester base oil may be a polymer of an ester of an unsaturated acid and an alcohol.

  As the monohydric alcohol, those having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms are usually used. Such alcohols may be linear or branched, It may be saturated or unsaturated. Specific examples of the alcohol having 1 to 24 carbon atoms include methanol, ethanol, linear or branched propanol, linear or branched butanol, and linear or branched pentanol. , Linear or branched hexanol, linear or branched heptanol, linear or branched octanol, linear or branched nonanol, linear or branched decanol , Linear or branched undecanol, linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol, linear or branched Pentadecanol, linear or branched hexadecanol, linear or branched heptadecanol, linear or branched octadecanol, linear or branched nonade Nord, linear or branched icosanol, linear or branched heicosanol, linear or branched docosanol, linear or branched tricosanol, linear or branched Examples thereof include tetracosanol and a mixture thereof.

  As the polyhydric alcohol, those having 2 to 10 valences, preferably 2 to 6 valences are usually used. Specific examples of the divalent to 10-valent polyhydric alcohol include, for example, ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, and polypropylene glycol (3 to 3 of propylene glycol). 15-mer), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1, Dihydric alcohols such as 3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentylglycol; glycerin, polyglycerin (glycerin 2 ~ Octamer, eg diglycerin, trig Serine, tetraglycerin, etc.), trimethylol alkanes (trimethylol ethane, trimethylol propane, trimethylol butane, etc.) and their 2-to 8-mer, pentaerythritol and their 2-to 4-mer, 1,2,4- Butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, etc. Polyhydric alcohols; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, and mixtures thereof And the like.

  Among these polyhydric alcohols, ethylene glycol, diethylene glycol, polyethylene glycol (ethylene glycol 3-10 mer), propylene glycol, dipropylene glycol, polypropylene glycol (propylene glycol 3-10 mer), 1,3- Propanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, glycerin, diglycerin, triglycerin, trimethylolalkane (trimethylolethane, trimethylolpropane, trimethylol Methylol butane and the like, and dimers and tetramers thereof, pentaerythritol, dipentaerythritol, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetrio Le, 1,2,3,4 butane tetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, divalent to hexavalent polyhydric alcohols, and mixtures thereof, such as mannitol and the like are preferable. Furthermore, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, sorbitan, and a mixture thereof are more preferable. Among these, neopentyl glycol, trimethylol ethane, trimethylol propane, pentaerythritol, and a mixture thereof are most preferable because higher thermal / oxidative stability can be obtained.

  Of the acids constituting the ester used in the present invention, as the monobasic acid, a fatty acid having 2 to 24 carbon atoms is usually used, and the fatty acid may be linear or branched and saturated. Or unsaturated. Specifically, for example, acetic acid, propionic acid, linear or branched butanoic acid, linear or branched pentanoic acid, linear or branched hexanoic acid, linear or branched Branched heptanoic acid, linear or branched octanoic acid, linear or branched nonanoic acid, linear or branched decanoic acid, linear or branched undecanoic acid, Linear or branched dodecanoic acid, linear or branched tridecanoic acid, linear or branched tetradecanoic acid, linear or branched pentadecanoic acid, linear or branched Hexadecanoic acid, linear or branched heptadecanoic acid, linear or branched octadecanoic acid, linear or branched hydroxyoctadecanoic acid, linear or branched nonadecanoic acid, Linear or branched icosanoic acid, linear or branched Saturated fatty acids such as helicosanoic acid, linear or branched docosanoic acid, linear or branched tricosanoic acid, linear or branched tetracosanoic acid; acrylic acid, methacrylic acid, linear Or branched butenoic acid, linear or branched pentenoic acid, linear or branched hexenoic acid, linear or branched heptenoic acid, linear or branched octene Acid, linear or branched nonenoic acid, linear or branched decenoic acid, linear or branched undecenoic acid, linear or branched dodecenoic acid, linear or Branched tridecenoic acid, linear or branched tetradecenoic acid, linear or branched pentadecenoic acid, linear or branched hexadecenoic acid, linear or branched heptadecenoic acid , Linear or branched octadecenoic acid, linear Or branched hydroxyoctadecenoic acid, linear or branched nonadecenoic acid, linear or branched icosenoic acid, linear or branched henicosenoic acid, linear or branched Docosenoic acid, linear or branched tricosenoic acid, unsaturated fatty acids such as linear or branched tetracosenoic acid; and mixtures thereof. Among these, from the point that lubricity and handleability are further improved, saturated fatty acids having 3 to 20 carbon atoms, unsaturated fatty acids having 3 to 22 carbon atoms and mixtures thereof are particularly preferable, and saturated fatty acids having 4 to 18 carbon atoms. More preferred are unsaturated fatty acids having 3 to 18 carbon atoms and mixtures thereof.

  Examples of the polybasic acid include dibasic acids having 2 to 16 carbon atoms and trimellitic acid. The dibasic acid having 2 to 16 carbon atoms may be linear or branched, and may be saturated or unsaturated. Specifically, for example, ethanedioic acid, propanedioic acid, linear or branched butanedioic acid, linear or branched pentanedioic acid, linear or branched hexanedioic acid, Linear or branched heptanedioic acid, linear or branched octanedioic acid, linear or branched nonanedioic acid, linear or branched decanedioic acid, linear Linear or branched undecanedioic acid, linear or branched dodecanedioic acid, linear or branched tridecanedioic acid, linear or branched tetradecanedioic acid, linear or Branched heptadecanedioic acid, linear or branched hexadecanedioic acid, linear or branched hexenedioic acid, linear or branched heptenedioic acid, linear or branched Octenedioic acid, linear or branched nonene diacid, linear or branched decenedioic acid, linear Or branched undecenedioic acid, linear or branched dodecenedioic acid, linear or branched tridecenedioic acid, linear or branched tetradecenedioic acid, linear or branched Examples thereof include branched heptadecene diacid, linear or branched hexadecene diacid, and mixtures thereof.

The combination of the alcohol and the acid forming the ester base oil is arbitrary and not particularly limited. As ester which can be used by this invention, the following ester can be mentioned, for example, These ester may be individual, and may combine 2 or more types.
(A) ester of monohydric alcohol and monobasic acid (b) ester of polyhydric alcohol and monobasic acid (c) ester of monohydric alcohol and polybasic acid (d) polyhydric alcohol and polybasic acid Ester (e) Mixture of monohydric alcohol and polyhydric alcohol, mixed ester of polybasic acid (f) Mixed ester of polyhydric alcohol and mixture of monobasic acid and polybasic acid (g) Monohydric alcohol And a mixture of a polyhydric alcohol and a mixture of a monobasic acid and a mixture of a polybasic acid (h) a polymer of an ester of a monohydric alcohol and an unsaturated monobasic acid

  Among these, (b) ester of polyhydric alcohol and monobasic acid, (c) ester of monohydric alcohol and polybasic acid, or (h) It is preferably a polymer of an ester of a monohydric alcohol and an unsaturated monobasic acid, and (h) a polymer of an ester of a monohydric alcohol and an unsaturated monobasic acid is more preferred.

  In the present invention, the ester obtained when a polyhydric alcohol is used as the alcohol component may be a complete ester in which all the hydroxyl groups in the polyhydric alcohol are esterified, or a part of the hydroxyl groups are not esterified and remain as hydroxyl groups. The remaining partial ester may be used. The organic acid ester obtained when a polybasic acid is used as the acid component may be a complete ester obtained by esterifying all carboxyl groups in the polybasic acid, or a part of the carboxyl groups may not be esterified. It may be a partial ester remaining as a carboxyl group.

  The iodine value of the ester base oil used in the present invention is preferably 0 to 5, more preferably 0 to 3, further preferably 0 to 2, and most preferably 0 to 1. When the iodine value of the ester base oil is within the above range, the obtained lubricating oil has good heat and oxidation stability. In addition, the iodine value here is a value measured by an indicator titration method according to JIS K 0070 “Method for measuring acid value, saponification value, ester value, iodine value, hydroxyl value, and unsaponified value of a chemical product”. Say.

The kinematic viscosity of the ester base oil used in the present invention is not particularly limited, but the kinematic viscosity at 100 ° C. is preferably 10 mm ² / s or more, more preferably 20 mm ² / s or more, and still more preferably Is 50 mm ² / s or more, particularly preferably 200 m ² / s or more, and most preferably 500 mm ² / s or more. Further, the kinematic viscosity of the ester-based base oil is preferably not more than 10000 mm ² / s, more preferably not more than 5000 mm ² / s, more preferably not more than 2000 mm ² / s. When the kinematic viscosity at 100 ° C. of the ester base oil is 10 mm ² / s or less, the effect of improving the viscosity index is inferior, and the required low temperature viscosity characteristics may not be obtained. Moreover, when the kinematic viscosity at 100 ° C. of the ester base oil is 10000 mm ² / s or more, the effect of improving the viscosity index is inferior, and the required low-temperature viscosity characteristics may not be obtained.

  The pour point and viscosity index of the ester base oil used in the present invention are not particularly limited, but the pour point is preferably −10 ° C. or lower, and more preferably −20 ° C. or lower. The viscosity index is preferably 100 or more, more preferably 120 or more, still more preferably 150 or more, particularly preferably 200 or more, and most preferably 230 or more.

  The ester base oil used in the present invention may be composed of only one kind of the ester compound described above, or may be composed of a mixture of two or more kinds.

  The blending ratio of the ester base oil in the lubricating oil composition of the present invention is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, particularly preferably based on the total amount of the base oil. It is 7 mass% or more, and most preferably 8 mass% or more. Moreover, it is preferably 80% by mass or less, more preferably 60% by mass or less, further preferably 40% by mass or less, particularly preferably 30% by mass or less, and most preferably 20% by mass or less. If the blending ratio of the ester base oil is less than 1% by mass, the required low-temperature viscosity characteristics and metal fatigue resistance may not be obtained, and if it exceeds 80% by mass, the required viscosity temperature Characteristics, low-temperature viscosity characteristics and metal fatigue resistance may not be obtained.

  The lubricating oil composition of the present invention may further contain one or more other synthetic base oils in addition to the mineral base oil and ester base oil according to the present invention. When the mineral base oil and ester base oil according to the present invention are used in combination with other synthetic base oils, the mineral base oil and ester base oil according to the present invention in the mixed base oil The ratio (the total content of the components (A) and (B)) is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more. .

  Other synthetic base oils include poly α-olefins or hydrides thereof, isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols, dialkyldiphenyl ethers, polyphenyl ethers, etc. Poly α-olefins are preferred. As the poly α-olefin, typically, an α-olefin oligomer or co-oligomer having 1 to 32 carbon atoms, preferably 6 to 16 (1-octene oligomer, decene oligomer, ethylene-propylene co-oligomer, etc.) and the like. Of the hydrides.

  The production method of the poly-α-olefin is not particularly limited. For example, Friedel-Crafts catalyst containing a complex of aluminum trichloride or boron trifluoride with water, alcohol (ethanol, propanol, butanol, etc.), carboxylic acid or ester. And a method of polymerizing α-olefin in the presence of a polymerization catalyst such as

The kinematic viscosity at 100 ° C. of a lubricating base oil comprising the mineral base oil and ester base oil according to the present invention (hereinafter referred to as “the lubricating base oil according to the present invention”) is 10 mm ² / It is preferably s or less, preferably 7 mm ² / s or less, more preferably 5 mm ² / s or less, and particularly preferably 4 mm ² / s or less. Further, the kinematic viscosity at 100 ° C. of the lubricating base oil according to the present invention is preferably 1.5 mm ² / s or more, more preferably 2 mm ² / s or more, further preferably 2.5 mm ² / s or more, particularly preferably. Is 3.0 mm ² / s or more, most preferably 3.5 mm ² / s or more. When the kinematic viscosity at 100 ° C. of the mineral base oil is less than 1.5 mm ² / s, the evaporation loss increases, and the necessary metal fatigue prevention property may not be obtained, which is not preferable. Moreover, since kinematic viscosity in 100 degreeC exceeds 10 mm < ² > / s, since a viscosity temperature characteristic and a low-temperature viscosity characteristic deteriorate, it is unpreferable.

The viscosity index of the lubricating base oil according to the present invention is preferably 120 or more, more preferably 130 or more, still more preferably 140 or more, particularly preferably 150 mm ² / s or more, and most preferably 160 or more.

  Further, the viscosity index improver contained in the lubricating oil composition of the present invention is not particularly limited, and specifically, non-dispersed or dispersed poly (meth) acrylate, non-dispersed or dispersed ethylene-α-olefin. Examples thereof include a copolymer or a hydride thereof, polyisobutylene or a hydride thereof, a styrene-diene hydrogenated copolymer, a styrene-maleic anhydride ester copolymer, and a polyalkylstyrene. A poly (meth) acrylate is preferably used. It is done. The viscosity index improver according to the present invention may be either non-dispersed or dispersed, but is more preferably non-dispersed.

  As a preferable aspect of the polymeth (acrylate) viscosity index improver according to the present invention, one or two monomers represented by the following general formula (1) (hereinafter referred to as “monomer (M-1)”) are used. The copolymer obtained by copolymerizing the above and monomers other than a monomer (M-1) is mentioned.

［上記一般式（１）中、Ｒ^１は水素原子またはメチル基を示し、Ｒ^２は炭素数１６以上の直鎖状または分枝状の炭化水素基を示す。］

[In the general formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a linear or branched hydrocarbon group having 16 or more carbon atoms. ]

  Although the monomer combined with the monomer (M-1) is arbitrary, for example, a monomer represented by the following general formula (2) (hereinafter referred to as “monomer (M-2)”) is preferable. The copolymer of the monomer (M-1) and the monomer (M-2) is a so-called non-dispersed poly (meth) acrylate viscosity index improver.

［上記一般式（２）中、Ｒ^３は水素原子またはメチル基を示し、Ｒ^４は炭素数１〜１５の直鎖状または分枝状の炭化水素基を示す。］

[In the general formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a linear or branched hydrocarbon group having 1 to 15 carbon atoms. ]

  Moreover, as another monomer combined with a monomer (M-1) and a monomer (M-2), the monomer (henceforth "monomer (M-3)") represented by the following general formula (3), and the following One or more selected from monomers represented by the general formula (4) (hereinafter referred to as “monomer (M-4)”) are preferable. The copolymer of the monomer (M-1) and the monomer (M-3) and / or (M-4) is a so-called dispersed poly (meth) acrylate viscosity index improver.

［上記一般式（３）中、Ｒ^５は水素原子またはメチル基を示し、Ｒ^６は炭素数１〜１８のアルキレン基を示し、Ｅ^１は窒素原子を１〜２個、酸素原子を０〜２個含有するアミン残基または複素環残基を示し、ａは０または１を示す。］

[In the general formula (3), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkylene group having 1 to 18 carbon atoms, E ¹ represents ¹ to 2 nitrogen atoms and 0 to 0 oxygen atoms. 2 represents an amine residue or a heterocyclic residue, and a represents 0 or 1. ]

Specific examples of the alkylene group having 1 to 18 carbon atoms represented by R ⁶ include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, Examples include an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, a pentadecylene group, a hexadecylene group, a heptadecylene group, and an octadecylene group (these alkylene groups may be linear or branched).

Specific examples of the group represented by E ¹ include a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, an anilino group, a toluidino group, a xylidino group, an acetylamino group, a benzoylamino group, Examples thereof include morpholino group, pyrrolyl group, pyrrolino group, pyridyl group, methylpyridyl group, pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl group, pyrrolidono group, imidazolino group, and pyrazino group.

［上記一般式（４）中、Ｒ^７は水素原子またはメチル基を示し、Ｅ^２は窒素原子を１〜２個、酸素原子を０〜２個含有するアミン残基または複素環残基を示す。］

[In the general formula (4), R ⁷ represents a hydrogen atom or a methyl group, and E ² represents an amine residue or a heterocyclic residue containing 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms. . ]

Specific examples of the group represented by E ² include a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, an anilino group, a toluidino group, a xylidino group, an acetylamino group, a benzoylamino group, and a morpholino group. Pyrrolyl group, pyrrolino group, pyridyl group, methylpyridyl group, pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl group, pyrrolidono group, imidazolino group, pyrazino group and the like.

  As preferable examples of the monomers (M-3) and (M-4), specifically, dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methyl-5-vinylpyridine, Examples thereof include morpholinomethyl methacrylate, morpholinoethyl methacrylate, N-vinylpyrrolidone and a mixture thereof.

  Although there is no restriction | limiting in particular about the copolymerization molar ratio of the copolymer of a monomer (M-1) and monomer (M-2)-(M-4), Monomer (M-1): Monomer (M-2) -(M-4) = 0.5: 99.5-70: 30 is preferable, More preferably, it is 5: 95-50: 50, More preferably, it is 10: 90-40: 60.

  Although the manufacturing method of the viscosity index improver according to the present invention is arbitrary, the poly (meth) acrylate viscosity index improver according to the present invention is, for example, in the presence of a polymerization initiator such as benzoyl peroxide, It can be easily obtained by radical solution polymerization of a mixture of the monomer (M-1) and the monomers (M-2) to (M-4).

  The PSSI (Permanent Cystability Index) of the viscosity index improver according to the present invention is preferably 40 or less, more preferably 30 or less, still more preferably 20 or less, particularly preferably 10 or less, and most preferably 5 or less. When PSSI exceeds 40, shear stability may be deteriorated.

  Note that “PSSI” here conforms to ASTM D 6022-01 (Standard Practication for Calculation of Permanent Shear Stable Stability Index), and ASTM D 6278-02 (Test Method for Stood For Shar. It means the permanent shear stability index of the polymer, calculated based on the data measured by Injector Apparatus.

The weight average molecular weight ( _Mw ) of the viscosity index improver according to the present invention is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 15,000 or more, and particularly preferably. Is 18,000 or more. Moreover, it is preferable that it is 200,000 or less, More preferably, it is 100,000 or less, More preferably, it is 80,000 or less, Especially preferably, it is 50,000 or less, Most preferably, it is 30,000 or less. When the weight average molecular weight is less than 5,000, the viscosity index improving effect is small and the viscosity temperature characteristics and low temperature viscosity characteristics are not only inferior, but the cost may increase, and the weight average molecular weight exceeds 200,000. May deteriorate the shear stability, solubility in base oil, storage stability, and metal fatigue resistance.

The ratio of the weight average molecular weight to number average molecular weight of the viscosity index improver according to the present invention _(M W / M _n) is preferably from 0.5 to 5.0, more preferably 1.0 to 3. 5, more preferably 1.5 to 3, particularly preferably 1.7 to 2.5. When the ratio of the weight average molecular weight to the number average molecular weight is 0.5 or less or 5.0 or more, not only the solubility in the base oil and the storage stability are deteriorated, but also the viscosity-temperature characteristics are deteriorated, and the fuel economy is improved. May get worse.

  The content of the viscosity index improver according to the present invention is preferably 0.1 to 50% by mass, more preferably 0.5 to 40% by mass, and still more preferably 1 to 30% by mass, based on the total amount of the lubricating oil composition. Especially preferably, it is 5-20 mass%. When the content of the viscosity index improver is less than 0.1% by mass, the effect of improving the viscosity index and the effect of reducing the product viscosity are reduced, and thus there is a possibility that the fuel economy cannot be improved. Also, if it exceeds 50% by mass, the product cost will increase significantly and the viscosity of the base oil will need to be reduced. Therefore, the lubrication performance under severe lubrication conditions (high temperature and high shear conditions) will be reduced and wear will be reduced. There is a concern that defects such as burn-in, seizure and fatigue failure may be the cause.

  The lubricating oil composition of the present invention includes a common general non-dispersed or dispersed poly (meth) acrylate, non-dispersed or dispersed ethylene-α-olefin copolymer in addition to the above-described preferred viscosity index improver. A polymer or a hydride thereof, polyisobutylene or a hydride thereof, a styrene-diene hydrogenated copolymer, a styrene-maleic anhydride ester copolymer, a polyalkylstyrene, or the like may further be contained.

  The lubricating oil composition of the present invention may be composed only of the above components (A), (B) and (C), but in order to further improve its performance, depending on its purpose Any additive commonly used in lubricating oils can be included. Examples of such additives include metal detergents, ashless dispersants, antioxidants, antiwear agents (or extreme pressure agents), friction modifiers, corrosion inhibitors, rust inhibitors, pour point depressants, Examples include additives such as demulsifiers, metal deactivators, and antifoaming agents.

  Metal-based detergents include alkali salts such as alkali metal sulfonates or alkaline earth metal sulfonates, alkali metal phenates or alkaline earth metal phenates, and alkali metal salicylates or alkaline earth metal salicylates, basic normal salts or overbased salts. Etc. In the present invention, one or more alkali metal or alkaline earth metal detergents selected from the group consisting of these, particularly alkaline earth metal detergents can be preferably used. In particular, a magnesium salt and / or a calcium salt is preferable, and a calcium salt is more preferably used.

  As the ashless dispersant, any ashless dispersant used in lubricating oils can be used. For example, a mono- or mono-chain having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule. Bisuccinimide, benzylamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or these And modified products of boron compounds, carboxylic acids, phosphoric acids, and the like. In use, one kind or two or more kinds arbitrarily selected from these can be blended.

  Examples of the antioxidant include ashless antioxidants such as phenols and amines, and metal antioxidants such as copper and molybdenum. Specifically, for example, as a phenol-based ashless antioxidant, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert- Butylphenol) and the like are amine-based ashless antioxidants such as phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, and dialkyldiphenylamine.

  As the antiwear agent (or extreme pressure agent), any antiwear agent / extreme pressure agent used in lubricating oils can be used. For example, sulfur-based, phosphorus-based, sulfur-phosphorus extreme pressure agents and the like can be used. Specifically, phosphites, thiophosphites, dithiophosphites, trithiophosphites Esters, phosphate esters, thiophosphate esters, dithiophosphate esters, trithiophosphate esters, amine salts thereof, metal salts thereof, derivatives thereof, dithiocarbamate, zinc dithiocarbamate, molybdenum dithiocarbamate, disulfide , Polysulfides, sulfurized olefins, sulfurized fats and oils, and the like. Among these, addition of a sulfur-based extreme pressure agent is preferable, and sulfurized fats and oils are particularly preferable.

Examples of the friction modifier include organic molybdenum compounds and ashless friction modifiers.
Organic molybdenum compounds include sulfur-containing organic molybdenum compounds such as molybdenum dithiophosphate and molybdenum dithiocarbamate, or molybdenum-amine complexes, molybdenum-succinimide complexes, organic acid molybdenum salts, and alcohol molybdenum salts. An organomolybdenum compound that does not contain can be used.

  As the ashless friction modifier, any compound usually used as a friction modifier for lubricating oils can be used. For example, an alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a straight chain having 6 to 30 carbon atoms. Amine compound, fatty acid ester, fatty acid amide, fatty acid, aliphatic alcohol, aliphatic ether, hydrazide (eg oleyl hydrazide), semicarbazide, urea, ureido, biuret having at least one chain alkyl group or straight chain alkenyl group in the molecule And ashless friction modifiers.

  As the friction modifier, either an organic molybdenum compound or an ashless friction modifier may be used alone, or both may be used in combination, but it is more preferable to use an ashless friction modifier.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, or imidazole compounds.

  Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.

  As the pour point depressant, for example, a polymethacrylate polymer compatible with the lubricating base oil to be used can be used.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Examples thereof include dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.

Examples of antifoaming agents include silicone oils having a kinematic viscosity at 25 ° C. of less than 0.1 to 100 mm ² / s, alkenyl succinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long chain fatty acids, methyl salicylates and o. -Hydroxybenzyl alcohol etc. are mentioned.

  When these additives are contained in the lubricating oil composition of the present invention, the content thereof is 0.01 to 10% by mass based on the total amount of the composition.

The kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention is preferably 10 mm ² / s or less, more preferably 8 mm ² / s or less, still more preferably 7 mm ² / s or less, particularly preferably 6 mm ² / s. s or less. Further, the kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention is preferably 3 mm ² / s or more, more preferably 4 mm ² / s or more, still more preferably 5 mm ² / s or more, and particularly preferably 5.5 mm ^2. / S or more. When the kinematic viscosity at 100 ° C. is less than 3 mm ² / s, the lubricity is insufficient, and the metal fatigue prevention property may be deteriorated. When it exceeds 10 mm ² / s, the necessary low-temperature viscosity and sufficient viscosity There is a possibility that temperature characteristics or fuel saving performance may not be obtained.

The kinematic viscosity at 40 ° C. of the lubricating oil composition of the present invention is preferably 50 mm ² / s or less, preferably 40 mm ² / s or less, more preferably 35 mm ² / s or less, particularly preferably 30 mm ² / s. Hereinafter, it is most preferably 25 mm ² / s or less. Further, the kinematic viscosity at 40 ° C. of the lubricating oil composition of the present invention is preferably 10 mm ² / s or more, more preferably 12 mm ² / s or more, further preferably 15 mm ² / s or more, particularly preferably 20 mm ² / s. That's it. When the kinematic viscosity at 40 ° C. is less than 10 mm ² / s, the lubricity is insufficient, and the metal fatigue prevention property may be deteriorated. When it exceeds 50 mm ² / s, the necessary low temperature viscosity and sufficient viscosity There is a possibility that temperature characteristics or fuel saving performance may not be obtained.

  The viscosity index of the lubricating oil composition of the present invention is preferably in the range of 140 to 300, more preferably 150 or more, still more preferably 170 or more, particularly preferably 190 or more, and most preferably 200 or more. When the viscosity index of the lubricating oil composition of the present invention is less than 140, the low temperature viscosity characteristics may be deteriorated. In addition, when the viscosity index of the lubricating oil composition of the present invention is 300 or more, low temperature fluidity is deteriorated, and there is a risk of problems due to insufficient solubility of additives and compatibility with sealing materials. There is.

  The BF viscosity at −30 ° C. of the lubricating oil composition of the present invention is preferably 1500 mPa · s or less, more preferably 1400 mPa · s or less, and still more preferably 1300 mPa · s or less. When the BF viscosity at −30 ° C. exceeds 1500 mPa · s, the low-temperature viscosity characteristics are insufficient, and thus there is a possibility that the required fuel saving performance and low-temperature startability cannot be achieved.

  The lubricating oil composition of the present invention has a BF viscosity at −40 ° C. of preferably 4500 mPa · s or less, more preferably 4200 mPa · s or less, still more preferably 4000 mPa · s or less, and particularly preferably 3800 mPa · s or less. The most preferable is 3500 mPa · s or less. When the BF viscosity at −40 ° C. exceeds 4500 mPa · s, the low-temperature viscosity characteristics are insufficient, and thus there is a possibility that the required fuel saving performance and low-temperature startability cannot be achieved.

  In addition, the brook field viscosity in -30 degreeC and -40 degreeC said by this invention means the value measured based on JPI-5S-26-99.

  The lubricating oil composition of the present invention having the above-described configuration has excellent viscosity temperature characteristics and low temperature performance, and is excellent in metal fatigue life, and is particularly suitable for an automatic transmission and / or a continuously variable transmission. Although used, it also exhibits excellent performance when used in lubricating oil for internal combustion engines.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Examples 1 and 2, Comparative Examples 1 to 6]
A lubricating oil composition having the composition shown in Table 2 was prepared using the base oils 1 to 4 having the properties shown in Table 1, the ester base oil (base oil 5), and additives.
(Base oil)
Base oil 1: hydrocracking / hydroisomerization base oil base oil 2: hydrocracking / hydroisomerization base oil base oil 3: paraffin hydrocracking base oil base oil 4: paraffin hydrocracking base oil Base oil 5: ester base oil (polymer of acrylic ester, 100 ° C. kinematic viscosity: 700 mm ² / s, viscosity index: 253)
(Additive)
PMA-1: non-dispersed polymethacrylate (weight average molecular weight: 20,000, PSSI: 0)
PMA-2: non-dispersed polymethacrylate (weight average molecular weight: 20,000, PSSI: 0)
PKG-1: Performance additive package

Of the base oils in Table 1, base oil 1 and base oil 2 were prepared by the following raw materials and production methods.
[Raw material wax]
The fraction separated by vacuum distillation in the step of refining the solvent refined base oil was subjected to hydrogenation after solvent extraction with furfural and then dewaxed with a methyl ethyl ketone-toluene mixed solvent. Table 3 shows the properties of the wax (hereinafter referred to as “WAX1”) that was removed during solvent dewaxing and obtained as slack wax.

[Manufacture of mineral oil base oil]
WAX1 was used as a raw material oil, and hydrotreating was performed using a hydrotreating catalyst. At this time, the reaction temperature and the liquid space velocity were adjusted so that the decomposition rate of normal paraffin in the raw material oil was 10% by mass or less.

  Next, about the to-be-processed object obtained by said hydrogenation process, in the temperature range of 315 degreeC-325 degreeC using the zeolite-type hydrodewaxing catalyst adjusted to noble metal content 0.1 to 5 weight%. Hydrodewaxing was performed.

  Furthermore, the to-be-processed object (raffinate) obtained by the above hydrodewaxing was hydrorefined using a hydrogenation catalyst. Thereafter, the light and heavy components were separated by distillation to obtain a mineral oil base oil having the composition and properties shown in Table 1. In Table 1, “the ratio of the components derived from normal paraffin in the urea adduct” is obtained by performing a gas chromatography analysis on the urea adduct obtained in the measurement of the urea adduct value. Yes (hereinafter the same).

[Fatigue life test]
Using each of the lubricating oil compositions of Examples 1 and 2 and Comparative Examples 1 to 6, a fatigue life test was conducted with a high-temperature rolling tester (1410 rpm, 120 ° C., 3.7 GPa) to determine L50 (50% failure probability). It was. The obtained results are shown in Table 2.

  From Table 2, the fatigue life and low temperature viscosity characteristics of the lubricating oil compositions of Examples 1 and 2 using a mineral base oil and an ester base oil having a urea adduct value of 4% by mass or less and a viscosity index of 100 or more are It turns out that it is excellent compared with Comparative Examples 1-6.

Claims (3)

A mineral base oil having a urea adduct value of 0.8% by mass to 2.5% by mass and a viscosity index of 100 or more;
An ester base oil;
1-30 mass% viscosity index improver , based on the total amount of the lubricating oil composition ,
And a BF viscosity at −30 ° C. is 1500 mPa · s or less . The raw oil containing normal paraffin as the mineral oil-based base oil has a urea adduct value of 0.8% by mass or more and 2.5% by mass or less and a viscosity index of 100 or more. The first step of hydrotreating a raw material oil containing normal paraffin using a hydrotreating catalyst, and the hydrolyzed dewaxing of the workpiece obtained by the first step using a hydrodewaxing catalyst A mineral oil-based group obtained by a hydrocracking / hydroisomerization step comprising: a second step; and a third step of hydrotreating the object to be treated obtained by the second step using a hydrotreating catalyst. The lubricating oil composition according to claim 1, wherein the lubricating oil composition is an oil.   The lubricating oil composition according to claim 2, wherein the raw material oil contains 50% by mass or more of slack wax obtained by solvent dewaxing of a lubricating base oil.