JP2013249483A - Lubricating oil composition and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition of a high viscosity index, in which an HTHS viscosity at 100°C is decreased while keeping the HTHS viscosity of a lubricating oil at 150°C constant, and a CCS viscosity at at most -35°C can be remarkably improved.SOLUTION: A fuel saving lubricating oil composition for an engine oil includes: a lubricating base oil including a specific first lubricating base oil component, and a specific second lubricating base oil component, wherein a content of the first lubricating base oil component is 10-99% by mass and a content of the second lubricating base oil component is 1-50% by mass based on the total amount of the lubricating base oil; and a viscosity index improver in which a ratio M1/M2 of a peak total area M1 between a chemical shift 36-38 ppm to a peak total area M2 between a chemical shift 64-66 ppm based on the total area of the total peak in a spectrum obtained byC-NMR is at least 0.20.

Description

  The present invention relates to a lubricating oil composition and a method for producing the same.

  Conventionally, in the field of lubricating oils, by adding additives such as viscosity index improvers and pour point depressants to lubricating base oils such as highly refined mineral oils, the viscosity-temperature characteristics and low-temperature viscosity characteristics of lubricating oils are improved. (For example, refer to Patent Documents 1 to 3). Further, as a method for producing a high viscosity index base oil, a method of refining a lubricating base oil by hydrocracking / hydroisomerization is known for a raw material oil containing natural or synthetic normal paraffin (for example, (See Patent Documents 4 to 6).

  As an evaluation index of the low temperature viscosity characteristics of the lubricating base oil and lubricating oil, a pour point, a cloud point, a freezing point, and the like are common. In addition, a technique for evaluating low-temperature viscosity characteristics based on a lubricating base oil such as the content of normal paraffin or isoparaffin is also known.

JP-A-4-36391 Japanese Patent Laid-Open No. 4-68082 Japanese Patent Laid-Open No. 4-120193 JP 2005-154760 A JP-T-2006-502298 JP-T-2002-503754

  Recently, the fuel efficiency required for lubricating oils has been increasing, and conventional lubricating base oils and viscosity index improvers are not necessarily sufficient in terms of viscosity-temperature characteristics and low-temperature viscosity characteristics. In particular, SAE10 class lubricating base oil or a lubricating oil composition containing this as a main component has high fuel economy and low temperature viscosity (CCS viscosity, MRV viscosity, etc.) while maintaining high temperature and high shear viscosity. It is difficult to achieve both levels.

  If only the low temperature viscosity is improved, a synthetic base oil such as a poly-α-olefin base oil or ester base oil, or a lubricating base oil excellent in low temperature viscosity such as a low viscosity mineral oil base oil may be used in combination. Although it is possible, the synthetic oil is expensive, and the low viscosity mineral oil base oil generally has a low viscosity index and a high NOACK evaporation amount. Therefore, when these lubricating base oils are blended, the manufacturing cost of the lubricating oil increases, and it becomes difficult to achieve a high viscosity index and low evaporation. Even when these conventional lubricating base oils are used, there is a limit to the improvement in fuel efficiency.

  The present invention has been made in view of such circumstances, and is excellent in fuel economy and low-temperature viscosity characteristics, and achieves both fuel economy and low-temperature viscosity at −35 ° C. or lower while maintaining high temperature and high shear viscosity. A high viscosity index lubricating oil composition capable of reducing the HTHS viscosity at 100 ° C. and significantly improving the CCS viscosity at −35 ° C. or lower while maintaining a constant 150 ° C. HTHS viscosity of the lubricating oil. The purpose is to do.

In order to solve the above problems, the present invention provides a first lubricating oil having a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 mm ² / s to 25 mm ² / s and a viscosity index of 120 or more. A first lubricating oil containing a base oil component and a second lubricating base oil component having a kinematic viscosity at 40 ° C. of 5 mm ² / s or more and less than 14 mm ² / s, based on the total amount of the lubricating base oil In the spectrum obtained by ¹³ C-NMR, the content of the base oil component is 10 to 99% by mass, the content of the second lubricant base oil component is 1 to 50% by mass, A viscosity index improver in which the ratio M1 / M2 of the peak total area M1 between the chemical shift 36-38 ppm to the peak total area M2 and the peak total area M2 between the chemical shifts 64-66 ppm is 0.20 or more; Containing A lubricating oil composition for fuel-saving engine oils is provided.

  Here, the “urea adduct value” in the present invention means a value measured by the following method. 100 g of weighed sample oil (lubricating base oil) is placed in a round bottom flask, 200 g of urea, 360 ml of toluene and 40 ml of methanol are added and stirred at room temperature for 6 hours. Thereby, white granular crystals are generated 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 recovered white crystals are put in 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 hydrocarbon component (urea adduct) thus obtained to the sample oil is defined as the urea adduct value.

  In the measurement of the urea adduct value, as the urea adduct, normal paraffin remains in the isoparaffin component that adversely affects the low-temperature viscosity characteristics, the thermal conductivity deterioration component, or the lubricating base oil. In this case, the normal paraffin in the case can be collected accurately and reliably, so that it is excellent as a low temperature viscosity characteristic and thermal conductivity evaluation index of the lubricating base oil. The inventors of the present invention have analyzed by using GC and NMR that the main component of the urea adduct is a normal paraffin and an isoparaffin urea adduct having 6 or more carbon atoms from the end of the main chain to the branch position. Confirm that there is.

  The lubricating base oil may have a distillation property such that the initial distillation point is 370 ° C. or less, the 90% distillation temperature is 430 ° C. or more, and the difference between the 90% distillation temperature and the 10% distillation temperature is 50 ° C. or more. preferable.

  “Initial distillation point” and “90% distillation temperature” as used in the present invention, and 10% distillation temperature, 50% distillation temperature and end point described later are measured in accordance with ASTM D 2887-97, respectively. It means point (IBP), 90% distillation temperature (T90), 10% distillation temperature (T10), 50% distillation temperature (T50) and end point (FBP). Hereinafter, for example, the difference between the 90% distillation temperature and the 10% distillation temperature is indicated as “T90−T10”.

  In the present invention, the viscosity index improver is preferably a poly (meth) acrylate viscosity index improver.

  The “poly (meth) acrylate” in the present invention is a general term for polyacrylate and polymethacrylate.

In the present invention, the poly (meth) acrylate viscosity index improver has a PSSI of 40 or less, and the ratio of the weight average molecular weight of the poly (meth) acrylate viscosity index improver to PSSI is 1 × 10 ⁴ or more. It is preferable that

  Here, “PSSI” in the present invention conforms to ASTM D 6022-01 (Standard Practicing for Calming of Permanent Shear Stability Index), and ASTM D 6278-02 (Test Method for Stood for Sto Permanent Shear Stability Index calculated based on data measured by European Diesel Injector Apparatus.

Moreover, it is preferable that the ratio of the HTHS viscosity at 150 ° C. and the HTHS viscosity at 100 ° C. of the lubricating oil composition of the present invention satisfies the condition represented by the following formula (A).
HTHS (100 ° C.) / HTHS (150 ° C.) ≦ 2.04 (A)
[Wherein, HTHS (100 ° C.) represents the HTHS viscosity at 100 ° C., and HTHS (150 ° C.) represents the HTHS viscosity at 150 ° C. ]

The present invention also provides a first lubricating base oil component having a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 mm ² / s to 25 mm ² / s and a viscosity index of 120 or more, Between the second lubricating base oil component having a kinematic viscosity at 5 ° C. of 5 mm ² / s or more and less than 14 mm ² / s, and a chemical shift of 36-38 ppm relative to the total area of all peaks in the spectrum obtained by ¹³ C-NMR And a viscosity index improver having a ratio M1 / M2 of the peak total area M2 between the peak total area M1 and the chemical shift of 64-66 ppm of not less than 0.20 to 0.20 or more. The content of the first lubricating base oil component is 10 to 99% by mass, the content of the second lubricating base oil component is 1 to 50% by mass, and the kinematic viscosity at 100 ° C. is 4 to 12 mm. ² / s Viscosity index is characterized in that to obtain a lubricating oil composition is 200 to 350, to provide a method for manufacturing a fuel-saving engine oil for lubricating oil compositions.

  The lubricating oil composition of the present invention is excellent in fuel economy and low temperature viscosity characteristics, and is also excellent in low evaporation. Therefore, without using a synthetic oil such as a poly-α-olefin base oil or an ester base oil, or a low viscosity mineral oil base oil, while maintaining the HTHS viscosity at 150 ° C., the fuel economy and at −35 ° C. or lower It is possible to achieve both low temperature viscosity and reduce NOACK evaporation. In particular, the kinematic viscosity at 40 ° C. and 100 ° C. and the HTHS viscosity at 100 ° C. of the lubricating oil can be reduced, and the CCS viscosity at −35 ° C. (MRV viscosity at −40 ° C.) can be remarkably improved.

  The lubricating oil composition of the present invention can also be suitably used for gasoline engines, diesel engines, gas engines for motorcycles, automobiles, power generation, cogeneration, etc., and further has a sulfur content of 50 mass. Not only can it be suitably used for these various engines using fuel of ppm or less, but it is also useful for various engines for ships and outboard motors. The lubricating oil composition of the present invention is particularly effective for improving the fuel consumption of an engine having a roller tappet type valve operating system in that it has excellent viscosity temperature characteristics.

  Moreover, according to the manufacturing method of the lubricating oil composition of this invention, the lubricating oil composition of this invention which has the outstanding characteristic as mentioned above can be obtained easily and reliably.

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

(Lubricant base oil)
The lubricating base oil used in the lubricating oil composition of the present invention has a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 mm ² / s to 25 mm ² / s and a viscosity index of 120 or more. 1 of the lubricating base oil component, and a kinematic viscosity at 40 ° C. contains the second lubricating base oil component is less than ^{5 mm} 2 / s or more 14 mm ² / s.

  The first lubricating base oil component may be a mineral base oil, a synthetic base oil, or a mixture of both as long as the urea adduct value, kinematic viscosity at 40 ° C., and viscosity index satisfy the above conditions. May be.

As the first lubricating base oil component, it is possible to satisfy the requirements of viscosity-temperature characteristics, low-temperature viscosity characteristics and thermal conductivity at a high level. Therefore, a raw oil containing normal paraffin is used as a urea adduct. Mineral oil base obtained by hydrocracking / hydroisomerization such that the value is 5% by mass or less, the kinematic viscosity at 40 ° C. is 14 mm ² / s to 25 mm ² / s and the viscosity index is 120 or more It is preferably an oil, a synthetic base oil, or a mixture of both.

  The urea adduct value of the first lubricating base oil component is 5% by mass or less as described above from the viewpoint of improving the low-temperature viscosity characteristics without impairing the viscosity-temperature characteristics and obtaining high thermal conductivity. Necessary, preferably 4.0% by mass or less, more preferably 3.5% by mass or less, further preferably 3.0% by mass or less, particularly preferably 2.5% by mass or less, and most preferably 2.0% by mass. % Or less. The urea adduct value of the first lubricating base oil component may be 0% by mass, but a sufficient low temperature viscosity characteristic and a lubricating base oil having a higher viscosity index can be obtained, and the dewaxing conditions are It is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 0.8% by mass or more from the viewpoint of relaxation and excellent economic efficiency.

Further, 40 ° C. kinematic viscosity of the first lubricating base oil component is required to be 14~25mm ² / s, preferably 14.5~20mm ² / s, more preferably 15~19mm ² / s, more preferably 15~18mm ² / s, particularly preferably 15~17mm ² / s, most preferably 15~16.5mm ² / s. The kinematic viscosity at 40 ° C. here refers to the kinematic viscosity at 40 ° C. defined in ASTM D-445. When the 40 ° C. kinematic viscosity of the first lubricating base oil component exceeds 25 mm ² / s, the low-temperature viscosity characteristics may be deteriorated, and sufficient fuel economy may not be obtained. When the 40 ° C. kinematic viscosity of the base oil component is less than 14 mm ² / s, the formation of an oil film at the lubrication site is insufficient, so that the lubricity is poor and the evaporation loss of the lubricating oil composition may increase.

  The viscosity index of the first lubricating base oil component needs to be 120 or more so that excellent viscosity characteristics can be obtained from low temperature to high temperature, and even if it is low viscosity, it is difficult to evaporate. Preferably, it is 125 or more, more preferably 130 or more, still more preferably 135 or more, and particularly preferably 140 or more. The upper limit of the viscosity index is not particularly limited, and is about 125 to 180, such as normal paraffin, slack wax, GTL wax, or isoparaffin mineral oil obtained by isomerizing these, complex ester base oil or HVI-PAO. The thing of about 150-250 like a base oil can also be used. However, for normal paraffin, slack wax, GTL wax and the like, or isoparaffin-based mineral oil obtained by isomerizing these, it is preferably 180 or less, more preferably 170 or less, in order to improve low-temperature viscosity characteristics. It is more preferably 160 or less, and particularly preferably 155 or less.

  For the production of the first lubricating base oil component, a raw material oil containing normal paraffin can be used. The raw material oil may be either mineral oil or synthetic oil, or may be a mixture of two or more of these. Further, the content of normal paraffin in the raw material oil is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, more preferably 90% by mass, based on the total amount of the raw material oil. Especially preferably, it is 95 mass% or more, Most preferably, it is 97 mass% or more.

  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 Examples include Tropsch wax, 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.

  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 above raw material oil undergoes a process of hydrocracking / hydroisomerization so that the urea adduct value, kinematic viscosity at 40 ° C., viscosity index, and T90-T10 satisfy the above-described conditions respectively. Thus, the first lubricating base oil component 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. 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 first lubricating base oil component obtained by the above production method, the other properties are not particularly limited as long as the urea adduct value, the 40 ° C. viscosity, and the viscosity index satisfy the above-mentioned conditions. It is preferable that the base oil component further satisfies the following conditions.

100 ° C. kinematic viscosity of the first lubricating base oil component is preferably not more than 5.0 mm ² / s, more preferably 4.5 mm ² / s or less, more preferably 4.3 mm ² / s or less, more preferably 4.2 mm ² / s or less, particularly preferably 4.0 mm ² / s or less, and most preferably not more than 3.9 mm ² / s. On the other hand, the 100 ° C. kinematic viscosity is preferably 2.0 mm ² / s or more, more preferably 3.0 mm ² / s or more, still more preferably 3.5 mm ² / s or more, and particularly preferably 3.7 mm. ² / s or more. The kinematic viscosity at 100 ° C. here refers to the kinematic viscosity at 100 ° C. as defined in ASTM D-445. When the 100 ° C. kinematic viscosity of the lubricating base oil component exceeds 5.0 mm ² / s, the low-temperature viscosity characteristics may be deteriorated, and sufficient fuel economy may not be obtained. 2.0 mm ² / s In the following cases, the formation of an oil film at the lubrication site is insufficient, resulting in poor lubricity, and the evaporation loss of the lubricating oil composition may be increased.

  Further, the pour point of the first lubricating base oil component depends on the viscosity grade of the lubricating base oil, but is preferably -10 ° C or lower, more preferably -12.5 ° C or lower, still more preferably -15 ° C. Hereinafter, it is most preferably -17.5 ° C or less, particularly preferably -20 ° C or less. If the pour point exceeds the upper limit, the low temperature fluidity of the entire lubricating oil using the lubricating base oil component may be reduced. The pour point of the first lubricating base oil component is preferably −50 ° C. or higher, more preferably −40 ° C. or higher, still more preferably −30 ° C. or higher, and particularly preferably −25 ° C. or higher. When the pour point is lower than the lower limit, the viscosity index of the entire lubricating oil using the lubricating base oil component is lowered, and there is a possibility that fuel economy is deteriorated. In addition, the pour point as used in the field of this invention means the pour point measured based on JISK2269-1987.

  The iodine value of the first lubricating base oil component is preferably 1 or less, more preferably 0.5 or less, still more preferably 0.3 or less, particularly preferably 0.15 or less, and most preferably Is 0.1 or less. Further, it may be less than 0.01, but from the viewpoint of the small effect that is commensurate with it and the economy, it is preferably 0.001 or more, more preferably 0.01 or more, and still more preferably 0.03. Above, especially preferably 0.05 or more. By setting the iodine value of the lubricating base oil component 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 JIS K0070 "the acid value of a chemical product, the saponification value, the iodine value, the hydroxyl value, and the unsaponification value."

  The sulfur content in the first lubricating base oil component is not particularly limited, but is preferably 50 ppm by mass or less, more preferably 10 ppm by mass or less, still more preferably 5 ppm by mass or less, particularly preferably. 1 mass ppm or less. By setting the sulfur content to 50 ppm by mass or less, excellent thermal and oxidation stability can be achieved.

  The amount of evaporation loss of the first lubricating base oil component is preferably NOACK evaporation of 25% by mass or less, more preferably 21 or less, and even more preferably 18% by mass or less. When the NOACK evaporation amount of the lubricating base oil component exceeds 25% by mass, the evaporation loss of the lubricating oil is large, which causes an increase in viscosity and the like, which is not preferable. Here, the NOACK evaporation amount is a value obtained by measuring the evaporation amount of the lubricating oil measured in accordance with ASTM D 5800.

  The initial boiling point (IBP) of the first lubricating base oil component is preferably 320 to 390 ° C, more preferably 330 to 380 ° C, and still more preferably 340 to 370 ° C. Moreover, 10% distillation temperature (T10) becomes like this. Preferably it is 370-430 degreeC, More preferably, it is 380-420 degreeC, More preferably, it is 390-410 degreeC. The 50% distillation point (T50) is preferably 400 to 470 ° C, more preferably 410 to 460 ° C, and still more preferably 420 to 450 ° C. Moreover, 90% distillation point (T90) becomes like this. Preferably it is 430-500 degreeC, More preferably, it is 440-490 degreeC, More preferably, it is 450-480 degreeC. Moreover, an end point (FBP) becomes like this. Preferably it is 450-520 degreeC, More preferably, it is 460-510 degreeC, More preferably, it is 470-500 degreeC.

  Moreover, regarding the distillation property of the first lubricating base oil component, T90-T10 is preferably 30 to 90 ° C, more preferably 40 to 80 ° C, and still more preferably 50 to 70 ° C. Moreover, FBP-IBP becomes like this. Preferably it is 90-150 degreeC, More preferably, it is 100-140 degreeC, More preferably, it is 110-130 degreeC. Moreover, T10-IBP becomes like this. Preferably it is 10-60 degreeC, More preferably, it is 20-50 degreeC, More preferably, it is 30-40 degreeC. Moreover, FBP-T90 becomes like this. Preferably it is 5-60 degreeC, More preferably, it is 10-45 degreeC, More preferably, it is 15-35 degreeC.

  In the first lubricating base oil, by setting IBP, T10, T50, T90, FBP, T90-T10, FBP-IBP, T10-IBP, and FBP-T90 within the above preferred ranges, the low temperature viscosity can be further increased. Improvement and further reduction in evaporation loss are possible. In addition, about each of T90-T10, FBP-IBP, T10-IBP, and FBP-T90, when the distillation range is made too narrow, the yield of lubricating base oil is deteriorated, which is not preferable in terms of economy. .

The first% _{C p} value of the lubricating base oils of the present invention is preferably 80 or more, more preferably 82 to 99, more preferably 85 to 98, particularly preferably 90 to 97. If the% C _p of the lubricating 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 lubricating base oil The effectiveness of the additive tends to decrease. Further, when the% C _p value of the lubricating base oil exceeds 99, the additive solubility will tend to be lower.

The first% _{C N} of the lubricating base oil of the present invention is preferably 20 or less, more preferably 15 or less, more preferably 1 to 12, particularly preferably 3 to 10. If the% C _N value of the lubricating base oil exceeds 20, the viscosity - temperature characteristic, heat 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 first lubricating base oil of the present invention is preferably 0.7 or less, more preferably 0.6 or less, more preferably 0.1 to 0.5. When% C _A of the lubricating base oil exceeds 0.7, the viscosity - temperature characteristic, heat and oxidation stability and frictional properties will tend to be reduced. Moreover,% C _A of the lubricating base oil of the 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 first lubricating% in base oil _{C P} and% _{C N} of the present _invention,% is preferred that C P /% _{C N} is 7 or greater, more not less than 7.5 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 the lubricating 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 the total number of aromatic carbons to the total number of carbons. That is, the preferred 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 lubricating base oil containing no naphthene is obtained by the above method. is% C _N may indicate a value greater than zero.

In the lubricating oil composition of the present invention, as the first lubricating base oil component, a lubricating base oil having a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 to 25 mm ² / s and a viscosity index of 120 or more is used. 1 type may be used independently and 2 or more types may be used together.

  The content ratio of the first lubricating base oil component is 10 to 99% by mass, preferably 30 to 95% by mass, more preferably 50 to 90% by mass, and still more preferably based on the total amount of the lubricating base oil. Is 60 to 85% by mass, most preferably 65 to 80% by mass. When the said content rate is less than 10 mass%, there exists a possibility that the required low temperature viscosity and fuel-saving performance may not be obtained.

Moreover, the lubricating oil composition of this invention contains the 2nd lubricating base oil component whose kinematic viscosity in 40 degreeC is 5-14 mm < ² > / s as a structural component of lubricating base oil.

  The second lubricating base oil component is not particularly limited as long as the above conditions are satisfied. Examples of the mineral base oil include solvent refined mineral oil, hydrocracked mineral oil, hydrorefined mineral oil, and solvent dewaxed base oil. It is done.

  Synthetic base oils include poly α-olefins or hydrides thereof, isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridec Decyl adipate, di-2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, dialkyl Examples thereof include diphenyl ether and polyphenyl ether, and among them, poly α-olefin is preferable. As the poly α-olefin, typically, an oligomer or co-oligomer (1-octene oligomer, decene oligomer, ethylene-propylene co-oligomer, etc.) having 2 to 32 carbon atoms, preferably 6 to 16 carbon atoms, and those. Of the hydrides.

The kinematic viscosity at 40 ° C. of the second lubricating base oil component needs to be less than 14 mm ² / s, preferably 13 mm ² / s or less, more preferably 12 mm ² / s or less, and even more preferably 11 mm. ² / s or less, particularly preferably 10 mm ² / s or less. On the other hand, the 40 ° C. kinematic viscosity needs to be 5 mm ² / s or more, preferably 6 mm ² / s or more, more preferably 7 mm ² / s or more, still more preferably 8 mm ² / s or more, and particularly preferably. Is 9 mm ² / s or more. When the kinematic viscosity at 40 ° C. is less than 5 mm ² / s, there is a risk of causing problems in oil film retention and evaporation at the lubrication site, which is not preferable. When the kinematic viscosity at 40 ° C. is 14 mm ² / s or more, the combined use effect with the first lubricating base oil cannot be obtained.

  The viscosity index of the second lubricating base oil component is preferably 80 or more, more preferably 100 or more, more preferably 110 or more, still more preferably 120 or more, particularly from the viewpoint of viscosity-temperature characteristics. Preferably it is 128 or more, Preferably it is 150 or less, More preferably, it is 140 or less, More preferably, it is 135 or less. When the viscosity index is less than 80, it is not preferable because effective energy saving performance may not be obtained. Moreover, the composition excellent in the low temperature characteristic can be obtained by making a viscosity index into 150 or less.

Further, the kinematic viscosity at 100 ° C. of the second lubricating base oil component is preferably 3.5 mm ² / s or less, more preferably 3.3 mm ² / s or less, still more preferably 3.1 mm ² / s or less, more preferably 3.0 mm ² / s or less, particularly preferably 2.9 mm ² / s or less, and most preferably not more than 2.8 mm ² / s. On the other hand, the 100 ° C. kinematic viscosity is preferably 2 mm ² / s or more, more preferably 2.3 mm ² / s or more, still more preferably 2.4 mm ² / s or more, and particularly preferably 2.5 mm ² / s or more. . When the kinematic viscosity at 100 ° C. of the lubricating base oil is less than 2 mm ² / s, the evaporation loss may be too large, and when the kinematic viscosity at 100 ° C. exceeds 3.5 mm ² / s, the low temperature viscosity The effect of improving the characteristics may be small.

  The urea adduct value of the second lubricating base oil component is preferably 4% by mass or less, more preferably 3.5% by mass or less from the viewpoint of improving the low-temperature viscosity characteristic without impairing the viscosity-temperature characteristic. More preferably, it is 3% by mass or less, and particularly preferably 2.5% by mass or less. In addition, the urea adduct value of the second lubricating base oil component may be 0% by mass, but a sufficient low temperature viscosity characteristic, high viscosity index and high flash point lubricating base oil can be obtained, and isomerization can be achieved. In terms of being able to relax the conditions and being excellent in economy, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 1.0% by mass or more.

The% C _p of the second lubricating base oil component is preferably 70 or more, more preferably 82 to 99.9, still more preferably 85 to 98, and particularly preferably 90 to 97. If the% C _{p of} the second lubricating base oil component is less than 70, the viscosity-temperature characteristics, thermal / oxidative stability and friction characteristics tend to decrease, and further, additives are added to the lubricating base oil. In this case, the effectiveness of the additive tends to decrease. In addition, when% C _p of the second lubricating base oil component exceeds 99, the solubility of additives tends to be lowered.

Moreover,% _{C N} of the second lubricating base oil component is preferably 30 or less, more preferably 1 to 15, more preferably from 3 to 10. If the% C _N value of the second lubricating base oil component exceeds 30, the viscosity - temperature characteristic, heat 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 second lubricating base oil component 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 second lubricating base oil component exceeds 0.7, the viscosity - temperature characteristic, heat and oxidation stability and frictional properties will tend to be reduced. Also, the% C _A of the second lubricating base oil component may be zero,% C by 0.1 or more _A, it is possible to further increase the solubility of additives.

Furthermore, the ratio of the% _{C P} and% _{C N} of the second lubricating base oil _component,% 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 the lubricating 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.

  The iodine value of the second lubricating base oil component is not particularly limited, but is preferably 6 or less, more preferably 1 or less, still more preferably 0.5 or less, and more preferably 0.3. In the following, it is more preferably 0.15 or less, and may be less than 0.01, but from the viewpoint of small effect and economic efficiency, it is preferably 0.001 or more, more preferably Is 0.05 or more. By making the iodine value of the lubricating base oil 6 or less, particularly 1 or less, the thermal and oxidation stability can be dramatically improved.

  The sulfur content in the second lubricating base oil component is preferably 10 ppm by mass or less from the viewpoint of further improving thermal and oxidation stability and reducing sulfur content. More preferably, it is 5 mass ppm or less, and further preferably 3 mass ppm or less.

  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 obtained second lubricating base oil component is preferably 50 mass ppm or less, and 10 mass ppm or less. It is more preferable that

  The nitrogen content in the second lubricating base oil component is not particularly limited, but is preferably 5 ppm by mass or less, more preferably 3 ppm by mass or less, and even more preferably 1 ppm by mass or less. If the nitrogen content exceeds 5 ppm by mass, the thermal and oxidation stability tends to decrease.

  The pour point of the second lubricating base oil component is preferably −25 ° C. or lower, more preferably −27.5 ° C. or lower, and further preferably −30 ° C. or lower. When the pour point exceeds the upper limit, the low temperature fluidity of the entire lubricating oil composition tends to be lowered.

  Of the distillation properties of the second lubricating base oil component by gas chromatography distillation, the initial boiling point (IBP) is preferably 285 to 325 ° C, more preferably 290 to 320 ° C, still more preferably 295 to 295. 315 ° C. Moreover, 10% distillation temperature (T10) becomes like this. Preferably it is 320-380 degreeC, More preferably, it is 330-370 degreeC, More preferably, it is 340-360 degreeC. The 50% distillation point (T50) is preferably 375 to 415 ° C, more preferably 380 to 410 ° C, and still more preferably 385 to 405 ° C. Moreover, 90% distillation point (T90) becomes like this. Preferably it is 370-440 degreeC, More preferably, it is 380-430 degreeC, More preferably, it is 390-420 degreeC. Moreover, an end point (FBP) becomes like this. Preferably it is 390-450 degreeC, More preferably, it is 400-440 degreeC, More preferably, it is 410-430 degreeC. Moreover, T90-T10 becomes like this. Preferably it is 25-85 degreeC, More preferably, it is 35-75 degreeC, More preferably, it is 45-65 degreeC. Moreover, FBP-IBP becomes like this. Preferably it is 70-150 degreeC, More preferably, it is 90-130 degreeC, More preferably, it is 90-120 degreeC. Moreover, T10-IBP becomes like this. Preferably it is 10-70 degreeC, More preferably, it is 20-60 degreeC, More preferably, it is 30-50 degreeC. Moreover, FBP-T90 becomes like this. Preferably it is 5-50 degreeC, More preferably, it is 10-45 degreeC, More preferably, it is 15-40 degreeC.

  In the second lubricating base oil component, by setting IBP, T10, T50, T90, FBP, T90-T10, FBP-IBP, T10-IBP, and FBP-T90 within the above preferred ranges, the low temperature viscosity can be further increased. Improvement and further reduction in evaporation loss. In addition, about each of T90-T10, FBP-IBP, T10-IBP, and FBP-T90, when the distillation range is made too narrow, the yield of lubricating base oil is deteriorated, which is not preferable in terms of economy. .

  In the present invention, the content of the second lubricating base oil component is 1% to 50% by weight, preferably 10 to 48% by weight, more preferably 12 to 45% by weight, based on the total amount of the lubricating base oil. More preferably, it is 15-40 mass%, Most preferably, it is 18-36 mass%. If the content is less than 1% by mass, the required low-temperature viscosity and fuel saving performance may not be obtained. If the content exceeds 50% by mass, the evaporation loss of the lubricating oil is large and causes an increase in viscosity. There is a risk of becoming.

  Although the lubricating base oil used in the present invention may consist of only the first lubricating base oil component and the second lubricating base oil component, the first lubricating base oil component and the second lubricating base oil component As long as each content of the lubricating base oil component is within the above range, a lubricating base oil component other than the first lubricating base oil component and the second lubricating base oil component may be further contained.

The kinematic viscosity at 40 ° C. of the lubricating base oil used in the present invention is preferably 20 mm ² / s or less, more preferably 16 mm ² / s or less, still more preferably 15 mm ² / s or less, particularly preferably 14 mm ² / s or less. Moreover, it is preferably 8 mm ² / s or more, more preferably 10 mm ² / s or more, and further preferably 12 mm ² / s or more.

The kinematic viscosity at 100 ° C. of the lubricating base oil used in the present invention is preferably 4.5 mm ² / s or less, more preferably 3.8 mm ² / s or less, still more preferably 3.7 mm ² / s or less, particularly preferably. Is 3.6 mm ² / s or less, preferably 2.3 mm ² / s or more, more preferably 2.8 mm ² / s or more, and still more preferably 3.3 mm ² / s or more. By setting the kinematic viscosity of the lubricating base oil within the above range, it is possible to obtain an excellent base oil due to a balance between evaporation loss and low temperature viscosity characteristics.

  The viscosity index of the lubricating base oil used in the present invention is preferably 100 or more, more preferably 120 or more, further preferably 130 or more, particularly preferably 135 or more, preferably 170 or less, more preferably 150 or less. More preferably, it is 140 or less. By making the viscosity index within the above range, a base oil having excellent viscosity-temperature characteristics can be obtained, and a lubricating oil composition having exceptionally high viscosity index and also excellent low-temperature viscosity characteristics can be obtained. .

  The NOACK evaporation amount of the lubricating base oil used in the present invention is preferably 10% by mass or more, more preferably 16% by mass or more, in order to obtain a lubricating oil composition having a good balance between low-temperature viscosity characteristics and evaporation loss. Preferably it is 18 mass% or more, More preferably, it is 20 mass% or more, Most preferably, it is 21 mass% or more, Preferably it is 30 mass% or less, More preferably, it is 25 mass% or less, Most preferably, it is 23 mass% or less. In particular, the NOACK evaporation amount of the lubricating base oil is 21 to 23% by mass and the viscosity index improver and other lubricating oil additives are blended in an amount of 10% by mass or more. It is possible to obtain a lubricating oil composition that has a high viscosity index, lowers the HTHS viscosity at 100 ° C., and is excellent in fuel economy.

  The initial boiling point is preferably 370 ° C. or lower, more preferably 350 ° C. or lower, further preferably 340 ° C. or lower, particularly preferably 330 ° C. or lower, regarding the distillation properties of the lubricating base oil used in the present invention. Is 260 ° C. or higher, more preferably 280 ° C. or higher, and further preferably 300 ° C. or higher. The 10% distillation temperature of the lubricating base oil is preferably 400 ° C. or lower, more preferably 390 ° C. or lower, still more preferably 380 ° C. or lower, preferably 320 ° C. or higher, more preferably 340 ° C. or higher. Preferably it is 360 degreeC or more. Further, the 90% distillation temperature of the lubricating base oil is preferably 430 ° C. or higher, more preferably 435 ° C. or higher, further preferably 440 ° C. or higher, preferably 480 ° C. or lower, more preferably 470 ° C. or lower, Preferably it is 460 degrees C or less. The end point (FBP) of the lubricating base oil is preferably 440 to 520 ° C, more preferably 460 to 500 ° C, and still more preferably 470 to 490 ° C. Further, the difference between the 90% distillation temperature and the 10% distillation temperature of the lubricating base oil is 50 ° C or higher, more preferably 60 ° C or higher, further preferably 70 ° C or higher, particularly preferably 75 ° C or higher, Further, it is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 85 ° C. or lower. The FBP-IBP of the lubricating base oil is preferably 135 to 200 ° C, more preferably 140 to 180 ° C, and still more preferably 150 to 170 ° C. Moreover, T10-IBP becomes like this. Preferably it is 20-100 degreeC, More preferably, it is 40-90 degreeC, More preferably, it is 50-80 degreeC. Moreover, FBP-T90 becomes like this. Preferably it is 5-50 degreeC, More preferably, it is 10-40 degreeC, More preferably, it is 15-35 degreeC. In the lubricating base oil, by setting IBP, T10, T50, T90, FBP, T90-T10, FBP-IBP, T10-IBP, and FBP-T90 within the above preferred ranges, the low temperature viscosity can be further improved. Further, evaporation loss can be further reduced.

Further, the ratio kv100 / T10 (unit: mm ² s ⁻¹ / ° C.) of T10 to the kinematic viscosity (kv100) at 100 ° C. of the lubricating base oil used in the present invention is preferably 0.007 to 0.015. Preferably it is 0.008-0.0095. Further, the ratio kv100 / T50 (unit: mm ² s ⁻¹ / ° C.) of T50 to the kinematic viscosity (kv100) at 100 ° C. of the lubricating base oil is preferably 0.006 to 0.009, more preferably 0. 0.007 to 0.0085. When kv100 / T10 and kv100 / T50 are each less than the above lower limit value, the yield of the lubricating base oil tends to be deteriorated, and it is not preferable in terms of economy, and is obtained when the above upper limit value is exceeded. There is a tendency for the evaporability of the lubricating oil composition to increase instead of the viscosity index.

Note that the urea adduct value,% C _P ,% C _A ,% C _N ,% C _P /% _CN value, sulfur content, and nitrogen content of the lubricating base oil used in the present invention are the same as those described above. The above-mentioned first lubricating base oil component, which depends on the value of the lubricating base oil component, the value of the second lubricating base oil component, or the other blendable lubricating base oil component and the content ratio thereof. The preferred range for each of the second lubricating base oil components is desirable.

In the spectrum obtained by nuclear magnetic resonance analysis ( ¹³ C-NMR), the viscosity index improver that can be used in the present invention is the chemical total peak M 1 and chemical chemistry between chemical shifts 36 to 38 ppm relative to the total area of all peaks. The ratio M1 / M2 of the total area M2 of peaks between shifts of 64-66 ppm is 0.20 or more.

  M1 / M2 needs to be 0.20 or more, preferably 0.3 or more, more preferably 0.4 or more, particularly preferably 0.5 or more, and most preferably 0.6 or more. M1 / M2 is preferably 3.0 or less, more preferably 2.0 or less, particularly preferably 1.0 or less, and most preferably 0.8 or less. When M1 / M2 is less than 0.20, not only the required fuel-saving property cannot be obtained, but also the low-temperature viscosity characteristics may be deteriorated. Moreover, when M1 / M2 exceeds 3.0, there exists a possibility that the required fuel-saving property may not be acquired, and there exists a possibility that solubility and storage stability may deteriorate.

In addition, a nuclear magnetic resonance analysis ( ^13C -NMR) spectrum is obtained about the polymer which isolate | separated dilution oil by rubber membrane dialysis etc., when a dilution oil is contained in a viscosity index improver.

In addition, the total area (M1) of the peak between chemical shifts 36-38 ppm with respect to the total area of all the peaks is a specific value of the polymethacrylate side chain with respect to the total integrated intensity of all the carbons measured by ¹³ C-NMR. This means the ratio of the integrated intensity derived from the β-branched structure, and the total area (M2) of the peak between chemical shifts 64-66 ppm relative to the total area of all peaks is the integral of all carbons measured by ¹³ C-NMR. It means the ratio of the integrated intensity derived from a specific linear structure of the polymethacrylate side chain to the total intensity.

M1 / M2 means a ratio of a specific β-branched structure and a specific linear structure of the polymethacrylate side chain, but other methods may be used as long as an equivalent result is obtained. In the ¹³ C-NMR measurement, a sample diluted with 0.5 g of a sample added with 3 g of deuterated chloroform was used, the measurement temperature was room temperature, the resonance frequency was 125 MHz, and the measurement method was a gated decoupling method. It was used.

From the above analysis,
(A) Sum of integral intensities with chemical shifts of about 10-70 ppm (sum of integral intensities due to total carbon of hydrocarbons), and (b) Sum of integral intensities with chemical shifts of 36-38 ppm (for specific β-branch structures) Sum of integral intensities due to), and (c) sum of integral intensities with chemical shifts of 64-66 ppm (sum of integral intensities due to specific linear structures)
Were measured, and the ratio (%) of (b) when (a) was set to 100% was calculated as M1. Further, the ratio (%) of (c) when (a) was set to 100% was calculated as M2.

［式（１）中、Ｒ^１は水素またはメチル基を示し、Ｒ^２は炭素数１６以上の直鎖または分枝状の炭化水素基、あるいは、酸素および／または窒素を含有する炭素数１６以上の直鎖または分枝状の有機基を示す。］ The viscosity index improver used in the present invention is not particularly limited as long as M1 / M2 satisfies 0.20 or more, but is preferably poly (meth) acrylate and is represented by the following formula (1). A polymer having a structural unit ratio of 0.5 to 70 mol% is preferred. The viscosity index improver may be either non-dispersed or dispersed.

[In the formula (1), R ¹ represents hydrogen or a methyl group, and R ² represents a straight chain or branched hydrocarbon group having 16 or more carbon atoms, or 16 or more carbon atoms containing oxygen and / or nitrogen. A linear or branched organic group. ]

R ² in formula (1) is preferably a linear or branched hydrocarbon group having 16 or more carbon atoms, more preferably a linear or branched hydrocarbon group having 18 or more carbon atoms. More preferably, it is a linear or branched hydrocarbon having 20 or more carbon atoms, particularly preferably a branched hydrocarbon group having 20 or more carbon atoms. The upper limit of the hydrocarbon group represented by R ² is not particularly limited, but is preferably a linear or branched hydrocarbon group having 100 or less carbon atoms. More preferably, it is a linear or branched hydrocarbon of 50 or less, more preferably a linear or branched hydrocarbon of 30 or less, particularly preferably 30 or less, a branched hydrocarbon. And most preferably 25 or less branched hydrocarbons.

  In the viscosity index improver, the proportion of the (meth) acrylate structural unit represented by the general formula (1) in the polymer is preferably 0.5 to 70 mol% as described above, and preferably 60 It is not more than mol%, more preferably not more than 50 mol%, still more preferably not more than 40 mol%, particularly preferably not more than 30 mol%. Further, it is preferably 1 mol% or more, more preferably 3 mol% or more, further preferably 5 mol% or more, and particularly preferably 10 mol% or more. If it exceeds 70 mol%, the effect of improving viscosity temperature characteristics and low temperature viscosity characteristics may be inferior, and if it is less than 0.5 mol%, the effect of improving viscosity temperature characteristics may be inferior.

  The viscosity index improver may contain a structural unit derived from an arbitrary (meth) acrylate structural unit or an arbitrary olefin in addition to the (meth) acrylate structural unit represented by the general formula (1).

  The method for producing the viscosity index improver is arbitrary, but for example, in the presence of a polymerization initiator such as benzoyl peroxide, a mixture of the monomer (M-1) and the monomers (M-2) to (M-4) Can be easily obtained by radical solution polymerization.

  The viscosity index improver preferably has a PSSI (Permanent Cystability Index) of 50 or less, more preferably 40 or less, still more preferably 35 or less, and particularly preferably 30 or less. Moreover, it is preferable that it is 5 or more, More preferably, it is 10 or more, More preferably, it is 15 or more, Most preferably, it is 20 or more. When PSSI is less than 5, the viscosity index improving effect is small and the cost may be increased. When PSSI is more than 50, shear stability and storage stability may be deteriorated.

The weight average molecular weight ( _Mw ) of the viscosity index improver is preferably 100,000 or more, more preferably 200,000 or more, still more preferably 250,000 or more, and particularly preferably 300,000. That's it. Moreover, it is preferably 1,000,000 or less, more preferably 700,000 or less, further preferably 600,000 or less, and particularly preferably 500,000 or less. When the weight average molecular weight is less than 100,000, the effect of improving the viscosity temperature characteristics and the effect of improving the viscosity index may be small and the cost may increase. When the weight average molecular weight exceeds 1,000,000, the shear stability There is a risk that the solubility in water and base oil and the storage stability may deteriorate.

The number average molecular weight (M _N ) of the viscosity index improver is preferably 50,000 or more, more preferably 800,000 or more, still more preferably 100,000 or more, and particularly preferably 120,000. That's it. Further, it is preferably 500,000 or less, more preferably 300,000 or less, further preferably 250,000 or less, and particularly preferably 200,000 or less. If the number average molecular weight is less than 50,000, the effect of improving the viscosity temperature characteristics and the effect of improving the viscosity index may be small and the cost may increase. If the weight average molecular weight exceeds 500,000, shear stability and There is a possibility that solubility in oil and storage stability may deteriorate.

The weight average molecular weight and PSSI ratio of the viscosity index improver _(M W / PSSI) is preferably 0.8 × 10 ⁴ or more, preferably 1.0 × 10 ⁴ or more, more preferably 1.5 × 10 ⁴ or more, more preferably 1.8 × 10 ⁴ or more, and particularly preferably 2.0 × 10 ⁴ or more. If M _W / PSSI is below 0.8 × 10 ^4, there is a possibility that the viscosity-temperature characteristic is deteriorated i.e. deteriorates fuel efficiency.

The ratio of the weight average molecular weight to the number average molecular weight (M _W / M _N ) of the viscosity index improver is preferably 0.5 or more, preferably 1.0 or more, more preferably 1.5 or more, and further Preferably it is 2.0 or more, Most preferably, it is 2.1 or more. _Further, it is preferred that the M W / _{M N} is 6.0 or less, more preferably 4.0 or less, more preferably 3.5 or less, particularly preferably 3.0 or less. When _MW / _MN is less than 0.5 or exceeds 6.0, the viscosity temperature characteristic may be deteriorated, that is, the fuel economy may be deteriorated.

The kinematic viscosity thickening ratio ΔKV40 / ΔKV100 at 40 ° C. and 100 ° C. of the viscosity index improver is preferably 4.0 or less, more preferably 3.5 or less, still more preferably 3.0 or less, particularly Preferably it is 2.5 or less, Most preferably, it is 2.3 or less. Further, ΔKV40 / ΔKV100 is preferably 0.5 or more, more preferably 1.0 or more, still more preferably 1.5 or more, and particularly preferably 2.0 or more.
If ΔKV40 / ΔKV100 is less than 0.5, the effect of increasing viscosity and solubility may be small and the cost may increase. If it exceeds 4.0, the effect of improving viscosity temperature characteristics and low temperature viscosity characteristics may be obtained. May be inferior. ΔKV40 means an increase in kinematic viscosity at 40 ° C. when 3.0% of a viscosity index improver is added to SK YUBASE4, and ΔKV100 is 3.0% of SKBASE YUBASE4. It means an increase in kinematic viscosity at 100 ° C. when added in%.

  The viscosity increase ratio ΔHTHS100 / ΔHTHS150 of the viscosity index improver at 100 ° C. and 150 ° C. is preferably 2.0 or less, more preferably 1.7 or less, still more preferably 1.6 or less, particularly Preferably it is 1.55 or less. ΔHTHS100 / ΔHTHS150 is preferably 0.5 or more, more preferably 1.0 or more, still more preferably 1.2 or more, and particularly preferably 1.4 or more. If ΔHTHS100 / ΔHTHS150 is less than 0.5, the effect of increasing viscosity and solubility may be small and the cost may increase, and if it exceeds 2.0, the effect of improving viscosity temperature characteristics and low temperature viscosity characteristics may be obtained. May be inferior.

  Here, ΔHTHS100 means an increase in HTHS viscosity at 100 ° C. when 3.0% of a viscosity index improver is added to YUBASE4 manufactured by SK Co., Ltd., and ΔHTHS150 is 3. It means an increase in HTHS viscosity at 150 ° C. when 0% is added. ΔHTHS100 / ΔHTHS150 means the ratio of the increase in HTHS viscosity at 100 ° C. to the increase in HTHS viscosity at 150 ° C. The HTHS viscosity at 100 ° C. here refers to the high temperature and high shear viscosity at 100 ° C. defined in ASTM D4683. Moreover, the HTHS viscosity at 150 ° C. indicates the high temperature and high shear viscosity at 150 ° C. defined in ASTM D4683.

  The content of the viscosity index improver in the lubricating oil composition of the present invention is preferably 0.01 to 50% by mass, more preferably 0.5 to 40% by mass, and still more preferably based on the total amount of the composition. Is 1 to 30% by mass, particularly preferably 5 to 20% by 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 diminished, 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.

  In order to further improve the performance, the lubricating oil composition of the present invention may contain any additive generally used in lubricating oils depending on the purpose. Examples of such additives include friction modifiers, metal detergents, ashless dispersants, antioxidants, antiwear agents (or extreme pressure agents), corrosion inhibitors, rust inhibitors, pour point depressants, Examples include additives such as demulsifiers, metal deactivators, and antifoaming agents.

  For example, the lubricating oil composition of the present invention may further contain a friction modifier selected from organic molybdenum compounds and ashless friction modifiers in order to improve fuel economy performance.

  Examples of the organic molybdenum compound used in the present invention include organic molybdenum compounds containing sulfur such as molybdenum dithiophosphate and molybdenum dithiocarbamate.

  Specific examples of preferred molybdenum dithiocarbamates include molybdenum sulfide diethyldithiocarbamate, molybdenum dipropyldithiocarbamate, molybdenum dibutyldithiocarbamate, molybdenum dipentyldithiocarbamate, molybdenum dihexyldithiocarbamate, molybdenum dihexyldithiocarbamate, molybdenum dioctyldithiocarbamate, and molybdenum disulfide. Decyl dithiocarbamate, sulfurized molybdenum didodecyl dithiocarbamate, molybdenum di (butylphenyl) dithiocarbamate, molybdenum di (nonylphenyl) dithiocarbamate, sulfurized oxymolybdenum diethyldithiocarbamate, sulfurized oxymolybdenum dipropyldithiocarbamate, sulfurized oxymolybdenum dibutyldithiocarbamate Oki Molybdenum dipentyldithiocarbamate, sulfurized oxymolybdenum dihexyldithiocarbamate, sulfurized oxymolybdenum dioctyldithiocarbamate, sulfurized oxymolybdenum didecyldithiocarbamate, sulfurized oxymolybdenum didodecyldithiocarbamate, sulfurized oxymolybdenum di (butylphenyl) dithiocarbamate, sulfurized oxymolybdenum di (nonylphenyl) Examples thereof include dithiocarbamate (the alkyl group may be linear or branched, and the bonding position of the alkyl group of the alkylphenyl group is arbitrary), and mixtures thereof. As these molybdenum dithiocarbamates, compounds having hydrocarbon groups having different carbon numbers and / or structures in one molecule can also be preferably used.

  In addition, organic molybdenum compounds containing sulfur other than these include molybdenum compounds (for example, molybdenum oxide such as molybdenum dioxide and molybdenum trioxide, orthomolybdic acid, paramolybdic acid, molybdic acid such as (poly) sulfurized molybdic acid, These metal salts of molybdate, molybdenum salts such as ammonium salts, molybdenum sulfides such as molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, and polysulfide molybdenum, molybdenum sulfides, metal salts or amine salts of molybdenum sulfides, chlorides Molybdenum halides such as molybdenum) and sulfur-containing organic compounds (eg, alkyl (thio) xanthates, thiadiazoles, mercaptothiadiazoles, thiocarbonates, tetrahydrocarbyl thiuram disulfides, bis (di (thio) hydrocarbons) Bildithiophosphonate) disulfide, organic (poly) sulfide, sulfurized ester, etc.) or other organic compounds, or the above-mentioned complexes of sulfur-containing molybdenum compounds such as molybdenum sulfide and sulfurized molybdic acid with alkenyl succinimides, etc. Can be mentioned.

  As the organic molybdenum compound, an organic molybdenum compound containing no sulfur as a constituent element can be used.

  Specific examples of organic molybdenum compounds that do not contain sulfur as a constituent element include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols. Complexes, molybdenum salts of organic acids and molybdenum salts of alcohols are preferred.

  In the lubricating oil composition of the present invention, when an organic molybdenum compound is used, its content is not particularly limited, but is preferably 0.001% by mass or more, more preferably 0, in terms of molybdenum element, based on the total amount of the composition. 0.005% by mass or more, more preferably 0.01% by mass or more, preferably 0.2% by mass or less, more preferably 0.15% by mass or less, still more preferably 0.10% by mass or less, particularly Preferably it is 0.08 mass% or less. When the content is less than 0.001% by mass, the thermal and oxidation stability of the lubricating oil composition becomes insufficient, and in particular, it tends to be impossible to maintain excellent cleanliness over a long period of time. On the other hand, when the content exceeds 0.2% by mass, an effect commensurate with the content cannot be obtained, and the storage stability of the lubricating oil composition tends to decrease.

  As the ashless friction modifier used in the present invention, 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 the number of carbon atoms. Amine compound, ester compound, amide compound, imide compound, ether compound, urea compound, hydrazide compound, fatty acid ester, fatty acid amide, fatty acid having at least one linear alkyl group or straight chain alkenyl group of 6 to 30 in the molecule Ashless friction modifiers such as aliphatic alcohols and aliphatic ethers.

［一般式（２）において、Ｒ^３は炭素数１〜３０の炭化水素基または機能性を有する炭素数１〜３０の炭化水素基、好ましくは炭素数１０〜３０の炭化水素基または機能性を有する炭素数１０〜３０の炭化水素基、より好ましくは炭素数１２〜２０のアルキル基、アルケニル基または機能性を有する炭化水素基、特に好ましくは炭素数１２〜２０のアルケニル基であり、Ｒ^４およびＲ^５は、それぞれ個別に、炭素数１〜３０の炭化水素基、機能性を有する炭素数１〜３０の炭化水素基または水素、好ましくは炭素数１〜１０の炭化水素基、機能性を有する炭素数１〜１０の炭化水素基または水素、さらに好ましくは炭素数１〜４の炭化水素基または水素、より好ましくは水素であり、Ｘは酸素または硫黄、好ましくは酸素を示す。］

［一般式（３）中、Ｒ^６は炭素数１〜３０の炭化水素基または機能性を有する炭素数１〜３０の炭化水素基であり、好ましくは炭素数１０〜３０の炭化水素基または機能性を有する炭素数１０〜３０の炭化水素基、より好ましくは炭素数１２〜２０のアルキル基、アルケニル基または機能性を有する炭化水素基、特に好ましくは炭素数１２〜２０のアルケニル基であり、Ｒ^７ _、Ｒ^８およびＲ^９は、それぞれ個別に、炭素数１〜３０の炭化水素基、機能性を有する炭素数１〜３０の炭化水素基または水素、好ましくは炭素数１〜１０の炭化水素基、機能性を有する炭素数１〜１０の炭化水素基または水素、より好ましくは炭素数１〜４の炭化水素基または水素、さらに好ましくは水素を示す。］ In addition, one or more compounds selected from the group consisting of nitrogen-containing compounds represented by the following general formulas (2) and (3) and acid-modified derivatives thereof, and various examples exemplified in International Publication No. 2005/037967 pamphlet Ashless friction modifiers may be mentioned.

[In General Formula (2), R ³ represents a hydrocarbon group having 1 to 30 carbon atoms or a hydrocarbon group having 1 to 30 carbon atoms, preferably a hydrocarbon group or functionality having 10 to 30 carbon atoms. A hydrocarbon group having 10 to 30 carbon atoms, more preferably an alkyl group having 12 to 20 carbon atoms, an alkenyl group or a hydrocarbon group having functionality, particularly preferably an alkenyl group having 12 to 20 carbon atoms, R ⁴ And R ⁵ are each independently a hydrocarbon group having 1 to 30 carbon atoms, a hydrocarbon group having 1 to 30 carbon atoms or hydrogen having functionality, preferably a hydrocarbon group having 1 to 10 carbon atoms, and functionality. It has a C1-C10 hydrocarbon group or hydrogen, more preferably a C1-C4 hydrocarbon group or hydrogen, more preferably hydrogen, and X represents oxygen or sulfur, preferably oxygen. ]

[In General Formula (3), R ⁶ is a hydrocarbon group having 1 to 30 carbon atoms or a hydrocarbon group having 1 to 30 carbon atoms having functionality, preferably a hydrocarbon group or function having 10 to 30 carbon atoms. A hydrocarbon group having 10 to 30 carbon atoms, more preferably an alkyl group having 12 to 20 carbon atoms, an alkenyl group or a functional hydrocarbon group, particularly preferably an alkenyl group having 12 to 20 carbon atoms, R ⁷ _, R ⁸ and R ⁹ are each independently a hydrocarbon group having 1 to 30 carbon atoms, a hydrocarbon group having 1 to 30 carbon atoms or a hydrogen having functionality, preferably a hydrocarbon having 1 to 10 carbon atoms. A hydrocarbon group having 1 to 10 carbon atoms or hydrogen having functionality, more preferably a hydrocarbon group or hydrogen having 1 to 4 carbon atoms, more preferably hydrogen. ]

Specific examples of the nitrogen-containing compound represented by the general formula (3) include hydrazides having 1 to 30 carbon atoms or functional hydrocarbon groups having 1 to 30 carbon atoms and derivatives thereof. is there. When R ⁶ is a hydrocarbon group having 1 to 30 carbon atoms or a functional hydrocarbon group having 1 to 30 carbon atoms, and R ^{7 to} R ⁹ are hydrogen, the hydrocarbon group or functionality having 1 to 30 carbon atoms Any of hydrazide having a hydrocarbon group having 1 to 30 carbon atoms, R ⁶ and R ^{7 to} R ⁹ is a hydrocarbon group having 1 to 30 carbon atoms or a hydrocarbon group having 1 to 30 carbon atoms having functionality. And when the remainder of R ^{7 to} R ⁹ is hydrogen, N-hydrocarbyl hydrazide having a hydrocarbon group having 1 to 30 carbon atoms or a hydrocarbon group having 1 to 30 carbon atoms having functionality (hydrocarbyl is a hydrocarbon group) Etc.).

  When the ashless friction modifier is used in the lubricating oil composition of the present invention, the content of the ashless friction modifier is preferably 0.01% by mass or more, more preferably 0.05% by mass, based on the total amount of the composition. % Or more, more preferably 0.1% by mass or more, preferably 3% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less. When the content of the ashless friction modifier is less than 0.01% by mass, the effect of reducing friction due to the addition tends to be insufficient, and when the content exceeds 3% by mass, the effect of an antiwear additive or the like. Tends to be inhibited, or the solubility of the additive tends to deteriorate.

  In the present invention, either one of the organic molybdenum compound or the ashless friction modifier may be used, or both may be used in combination, but it is more preferable to use an ashless friction modifier, such as glycerin oleate. It is particularly preferable to use a fatty acid ester ashless friction modifier and / or a urea friction modifier such as oleyl urea.

  Examples of metal detergents include alkali metal sulfonates or alkaline earth metal sulfonates, alkali metal phenates or alkaline earth metal phenates, and alkali salts such as alkali metal salicylates or alkaline earth metal salicylates, basic positive 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 or 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 corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, or imidazole compounds.

  Examples of the rust preventive 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, or 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.

Kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention is preferably from 4 to 12 mm ² / s, more preferably 4.5 mm ² / s or more as a lower limit, more preferably ^{5 mm} 2 / s or more, Especially preferably, it is 6 mm < ² > / s or more, Most preferably, it is 7 mm < ² > / s or more. The upper limit is preferably 11 mm ² / s or less, more preferably 10 mm ² / s or less, particularly preferably 9 mm ² / s or less, and most preferably 8 mm ² / s or less. If the kinematic viscosity at 100 ° C. is less than 4 mm ² / s, there is a risk of insufficient lubricity, and if it exceeds 12 mm ² / s, the necessary low temperature viscosity and sufficient fuel saving performance may not be obtained. is there.

  The viscosity index of the lubricating oil composition of the present invention is preferably in the range of 200 to 350, more preferably 210 to 300, still more preferably 220 to 300, particularly preferably 240 to 300, and most preferably 260. ~ 300. When the viscosity index of the lubricating oil composition of the present invention is less than 200, it may be difficult to improve fuel economy while maintaining the HTHS viscosity, and the low temperature viscosity at −35 ° C. is further reduced. May be difficult. In addition, when the viscosity index of the lubricating oil composition of the present invention is 350 or more, low temperature fluidity is deteriorated, and there is a risk that problems due to insufficient solubility of the additive and compatibility with the sealing material may occur. There is.

  In addition to the kinematic viscosity and viscosity index at 100 ° C. satisfying the above requirements, the lubricating oil composition of the present invention preferably satisfies the following requirements.

The kinematic viscosity at 40 ° C. of the lubricating oil composition of the present invention is preferably 4 to 50 mm ² / s, preferably 45 mm ² / s or less, more preferably 40 mm ² / s or less, and still more preferably 35 mm ² / s. s or less, particularly preferably 30 mm ² / s or less, and most preferably 27 mm ² / s or less. On the other hand, the 40 ° C. kinematic viscosity is preferably 5 mm ² / s or more, more preferably 10 mm ² / s or more, still more preferably 15 or more, and particularly preferably 20 or more. If the kinematic viscosity at 40 ° C. is less than 4 mm ² / s, there is a risk of insufficient lubricity, and if it exceeds 50 mm ² / s, the necessary low temperature viscosity and sufficient fuel saving performance may not be obtained. is there.

  The HTHS viscosity at 100 ° C. of the lubricating oil composition of the present invention is preferably 6.0 mPa · s or less, more preferably 5.5 mPa · s or less, and even more preferably 5.3 mPa · s or less. Particularly preferably, it is 5.0 mPa · s or less, and most preferably 4.5 mPa · s or less. Further, it is preferably 3.0 mPa · s or more, preferably 3.5 mPa · s or more, more preferably 3.8 mPa · s or more, particularly preferably 4.0 mPa · s or more, and most preferably 4.2 mPa · s or more. s or more. Here, the HTHS viscosity at 100 ° C. indicates the high temperature and high shear viscosity at 100 ° C. defined in ASTM D4683. When the HTHS viscosity at 100 ° C. is less than 3.0 mPa · s, there is a risk of high evaporability and insufficient lubricity. When it exceeds 6.0 mPa · s, the necessary low temperature viscosity and sufficient fuel saving Performance may not be obtained.

  The lubricating oil composition of the present invention has an HTHS viscosity at 150 ° C. of preferably 3.5 mPa · s or less, more preferably 3.0 mPa · s or less, and even more preferably 2.8 mPa · s or less. Particularly preferably, it is 2.7 mPa · s or less. Further, it is preferably 2.0 mPa · s or more, preferably 2.3 mPa · s or more, more preferably 2.4 mPa · s or more, particularly preferably 2.5 mPa · s or more, and most preferably 2.6 mPa · s. s or more. The HTHS viscosity at 150 ° C. here refers to the high temperature and high shear viscosity at 150 ° C. defined in ASTM ASTM D4683. When the HTHS viscosity at 150 ° C. is less than 2.0 mPa · s, there is a risk of high vaporization and insufficient lubricity. When it exceeds 3.5 mPa · s, the necessary low-temperature viscosity and sufficient fuel saving Performance may not be obtained.

In the lubricating oil composition of the present invention, it is preferable that the ratio of the HTHS viscosity at 100 ° C. to the HTHS viscosity at 150 ° C. satisfies the condition represented by the following formula (A).
HTHS (100 ° C.) / HTHS (150 ° C.) ≦ 2.04 (A)
[Wherein, HTHS (100 ° C.) represents the HTHS viscosity at 100 ° C., and HTHS (150 ° C.) represents the HTHS viscosity at 150 ° C. ]

  HTHS (100 ° C.) / HTHS (150 ° C.) is preferably 2.04 or less, more preferably 2.00 or less, still more preferably 1.98 or less, and even more preferably 1.80 or less. Particularly preferably, it is 1.70 or less. If HTHS (100 ° C.) / HTHS (150 ° C.) exceeds 2.04, sufficient fuel saving performance and low temperature characteristics may not be obtained. Further, HTHS (100 ° C.) / HTHS (150 ° C.) is preferably 0.50 or more, more preferably 0.70 or more, still more preferably 1.00 or more, and particularly preferably 1.30 or more. When HTHS (100 ° C.) / HTHS (150 ° C.) is less than 0.50, there is a possibility that the cost of the substrate is significantly increased and the solubility of the additive cannot be obtained.

  Since the lubricating oil composition of the present invention has the above-described configuration, it is excellent in fuel economy, low evaporation, and low-temperature viscosity characteristics, and it can be a synthetic oil such as poly-α-olefin base oil and ester base oil, Even without using a mineral oil base oil, it is possible to achieve both fuel economy and NOACK evaporation and low temperature viscosity at −35 ° C. or lower while maintaining the HTHS viscosity at 150 ° C. The kinematic viscosity at 100 ° C. and the HTHS viscosity at 100 ° C. can be reduced, and the CCS viscosity at −35 ° C. (MRV viscosity at −40 ° C.) can be significantly improved. For example, according to the lubricating oil composition of the present invention, the CCS viscosity at −35 ° C. can be made 2500 mPa · s or less, particularly 2300 mPa · s or less. Further, according to the lubricating oil composition of the present invention, the MRV viscosity at −40 ° C. can be 8000 mPa · s or less, particularly 6000 mPa · s or less.

  The use of the lubricating oil composition of the present invention is not particularly limited, but is suitably used as a fuel-saving engine oil, a fuel-saving gasoline engine oil, and a fuel-saving diesel engine oil.

  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.

[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 1 shows the properties of the wax (hereinafter referred to as “WAX1”) that was removed during solvent dewaxing and obtained as slack wax.

  Table 2 shows the properties of the wax obtained by further deoiling WAX1 (hereinafter referred to as “WAX2”).

  Table 3 shows the properties of WAX3 using an FT wax having a paraffin content of 95% by mass and a carbon number distribution of 20 to 80 (hereinafter referred to as “WAX3”).

[Manufacture of lubricating base oil]
WAX1, WAX2 and WAX3 were used as feedstocks, 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 the raw material oil was 5 mass% or more and the sulfur content of the oil to be treated was 10 mass ppm or less. “The decomposition rate of the feedstock is 5% by mass or more” means that the fraction of the treated oil that is lighter than the initial boiling point of the feedstock is 5% by mass or more based on the total feedstock Which is confirmed by gas chromatography.

  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 base oils 1 to 4 having the compositions and properties shown in Tables 4 and 5 were obtained by distillation. In addition, lubricating base oils 5 and 6 having the compositions and properties shown in Table 5 were obtained as hydrocracking base oils using WVGO as a raw material. In Tables 4 and 5, the “ratio of 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).

  Next, a polymethacrylate pour point depressant (weight average molecular weight: about 60,000) generally used for automotive lubricating oils was added to the lubricating base oils in Tables 4 and 5. The addition amount of the pour point depressant was three conditions of 0.3% by mass, 0.5% by mass and 1.0% by mass based on the total amount of the composition. Next, with respect to each of the obtained lubricating oil compositions, the MRV viscosity at −40 ° C. was measured, and the obtained results are shown in Tables 4 and 5.

[Examples 1-3, Comparative Examples 1-3]
In Examples 1 to 3 and Comparative Examples 1 to 3, lubricating oil compositions having the compositions shown in Tables 6 and 7 were prepared using the above base oils 1 to 5 and the additives shown below, respectively. In preparing the lubricating oil composition, the HTHS viscosity at 150 ° C. was set in the range of 2.55 to 2.65. Properties of the obtained lubricating oil composition are shown in Tables 6 and 7.
(Additive)
PK: Additive package (metal detergent (Ca salicylate Ca amount 2000 ppm), ashless dispersant (borated polybutenyl succinimide), antioxidant (phenolic, amine), antiwear (alkyl phosphoric acid) Zinc P amount 800 ppm), ester-based ashless friction modifier, urea-based ashless friction modifier), pour point depressant, defoaming agent, etc.).
MoDTC: Molybdenum dithiocarbamate.
VM-1: Non-dispersed polymethacrylate (alkyl methacrylate mixture (alkyl group: methyl group, straight chain alkyl group having 12 to 15 carbon atoms, straight chain alkyl group having 16 to 20 carbon atoms) 90 mol%, carbon number Copolymer obtained by polymerizing 10 mole% of alkyl methacrylate having 22 branched alkyl groups as a main constituent unit), M1 = 0.60, M2 = 0.95, M1 / M2 = 0.64, PSSI = 20, MW = 400,000, Mw / PSSI = 2 × 10 ⁴ , Mw / Mn = 2.2, ΔKV40 / ΔKV100 = 2.2, ΔHTHS100 / ΔHTHS150 = 1.51
VM-2: Dispersion type polymethacrylate (copolymer obtained by polymerizing dimethylaminoethyl methacrylate and alkyl methacrylate mixture (alkyl group: methyl group, linear alkyl group having 12 to 15 carbon atoms) as a main constituent unit ), M1 = 0.46, M2 = 3.52, M1 / M2 = 0.13, PSSI = 40, MW = 300,000, Mw / PSSI = 0.75 × 10 ⁴ , Mw / Mn = 4.0 , ΔKV40 / ΔKV100 = 3.3, ΔHTHS100 / ΔHTHS150 = 1.79

[Evaluation of lubricating oil composition]
About each lubricating oil composition of Examples 1-3 and Comparative Examples 1-3, kinematic viscosity at 40 ° C. and 100 ° C., viscosity index, NOACK evaporation (1 h, 250 ° C.), HTHS viscosity at 150 ° C. and 100 ° C., In addition, the CCS viscosity at −35 ° C. and the MRV viscosity at −40 ° C. were measured. Each physical property value was measured by the following evaluation method. The results obtained are shown in Table 6.
(1) Kinematic viscosity: ASTM D-445
(2) HTHS viscosity: ASTM D4683
(3) NOACK evaporation: ASTM D 5800
(4) CCS viscosity: ASTM D5293
(5) MRV viscosity: ASTM D3829

As shown in Table 6, the lubricating oil compositions of Examples 1 to 3 and Comparative Examples 1 to 3 have the same HTHS viscosity at 150 ° C., but the lubricating oil compositions of Comparative Examples 1 to 3 In comparison, the lubricating oil compositions of Examples 1 to 3 had low 40 ° C. kinematic viscosity, 100 ° C. kinematic viscosity, 100 ° C. HTHS viscosity and CCS viscosity, and good low temperature viscosity and viscosity temperature characteristics. From this result, the lubricating oil composition of the present invention is excellent in fuel economy and low temperature viscosity, without using a synthetic oil such as a poly-α-olefin base oil or an ester base oil, or a low viscosity mineral oil base oil. , While maintaining the high shear viscosity at 150 ° C., it is possible to achieve both fuel saving and low temperature viscosity at −35 ° C. or lower, especially reducing the kinematic viscosity of lubricating oil at 40 ° C. and 100 ° C. It can be seen that the lubricating oil composition can significantly improve the CCS viscosity at -35 ° C.

Claims (6)

A first lubricating base oil component having a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 mm ² / s to 25 mm ² / s and a viscosity index of 120 or more, and a kinematic viscosity at 40 ° C. A ^second lubricating base oil component that is 5 mm ² / s or more and less than 14 mm ² / s is contained, and the content of the first lubricating base oil component is 10 to 99% by mass based on the total amount of the lubricating base oil. A lubricating base oil having a content of the second lubricating base oil component of 1 to 50% by mass;
^{In the} spectrum obtained by ¹³ C-NMR, the ratio M1 / M2 of the peak total area M1 between the chemical shift 36-38 ppm and the peak total area M2 between the chemical shift 64-66 ppm relative to the total area of all peaks is 0. A viscosity index improver that is 20 or greater;
A lubricating oil composition for fuel-saving engine oils, comprising:   The lubricating base oil has a distillation property that the initial distillation point is 370 ° C. or less, the 90% distillation temperature is 430 ° C. or more, and the difference between the 90% distillation temperature and the 10% distillation temperature is 50 ° C. or more. The lubricating oil composition for fuel-saving engine oil according to claim 1.   The lubricating oil composition for fuel-saving engine oil according to claim 1 or 2, wherein the viscosity index improver is a poly (meth) acrylate viscosity index improver. The PS (SI) of the poly (meth) acrylate viscosity index improver is 40 or less, and the ratio of the weight average molecular weight of the poly (meth) acrylate viscosity index improver to PSSI is 1 × 10 ⁴ or more. The lubricating oil composition for fuel-saving engine oil according to claim 3. The ratio of the HTHS viscosity at 150 ° C. and the HTHS viscosity at 100 ° C. of the lubricating oil composition satisfies a condition represented by the following formula (A). Lubricating oil composition for fuel-saving engine oil.
HTHS (100 ° C.) / HTHS (150 ° C.) ≦ 2.04 (A)
[Wherein, HTHS (100 ° C.) represents the HTHS viscosity at 100 ° C., and HTHS (150 ° C.) represents the HTHS viscosity at 150 ° C. ] A first lubricating base oil component having a urea adduct value of 5% by mass or less, a kinematic viscosity at 40 ° C. of 14 mm ² / s to 25 mm ² / s, and a viscosity index of 120 or more;
A second lubricating base oil component having a kinematic viscosity at 40 ° C. of 5 mm ² / s or more and less than 14 mm ² / s;
^{In the} spectrum obtained by ¹³ C-NMR, the ratio M1 / M2 of the peak total area M1 between the chemical shift 36-38 ppm and the peak total area M2 between the chemical shift 64-66 ppm relative to the total area of all peaks is 0. A viscosity index improver that is 20 or greater;
, Based on the total amount of the lubricating base oil, the content of the first lubricating base oil component is 10 to 99% by mass, and the content of the second lubricating base oil component is 1 to 50% by mass. A method for producing a lubricating oil composition for fuel-saving engine oil, comprising obtaining a lubricating oil composition having a kinematic viscosity at 100 ° C. of 4 to 12 mm ² / s and a viscosity index of 200 to 350.