JP2005154760A - Lubricant base oil and method for producing the same, and lubricating oil composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant base oil having a high viscosity index and an excellent low temperature fluidity, and a lubricating oil composition which is excellent in a high viscosity index, high shear stability and high oxidation stability with a high flash point and a low density using the lubricant base oil. <P>SOLUTION: The lubricant base oil is based on hydrocarbons and has a viscosity index of 130 or higher, contains 90% or more of paraffinic components (%Cp) by the ring analysis and contains CCS viscosity of 3,000 mPa×s or less at -35°C, and a method for producing the same, and the lubricating oil composition using the lubricant base oil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lubricating base oil and a method for producing the same, and a lubricating oil composition containing the base oil, and more specifically, a lubricating base oil having a high viscosity index and excellent low-temperature fluidity, and a method for producing the same. The present invention also relates to a lubricating oil composition using the base oil and having excellent viscosity index and shear stability.

In general, lubricating oils are used in various fields for the purpose of essentially maintaining viscosity and preventing wear of contact members to impart lubricity. It is important for the performance of this lubricating oil to maintain an appropriate viscosity at a high temperature and fluidity at a low temperature. In addition, recently, there has been a demand for lubricating oil compositions to achieve energy and fuel savings by further reducing viscosity in a region where friction is not generated and reducing stirring resistance.
In recent years, high-viscosity index base oils having a viscosity index of 120 or more have been used as base oils for such energy-saving engine oils. It has been conventionally known that if the viscosity index is high, the oxidation stability is relatively improved. However, the high viscosity index base oil is generally produced by a solvent dewaxing method and is inferior in low-temperature fluidity. There were drawbacks. For example, Patent Document 1 discloses a high viscosity index base oil having a viscosity index of 120 or more, preferably 140 or more, but it is described that it is difficult to achieve a low pour point. Accordingly, there is a need for a lubricating base oil having a high viscosity index and excellent low temperature fluidity.

On the other hand, mineral-based lubricating base oils are mainly from the viewpoint of oxidation stability and energy saving, from solvent refined base oil (API classification GI), hydrorefined base oil (API classification GII), hydrocracked base oil ( API class GIII) and polyalphaolefins (API class GIV) have been developed for synthetic base oils.
However, in the conventional mineral oil base oil, when the viscosity index is insufficient, a method of increasing the apparent high temperature viscosity by blending a large amount of a viscosity index improver has been performed. Since this viscosity index improver is usually a high-molecular polymethacrylate or olefin copolymer, when used for a long time, the viscosity index improver is subjected to thermal and mechanical shearing. As a result, a decrease in viscosity is caused, and as a result, it becomes difficult to prevent wear due to viscosity retention, which is an essential purpose of the lubricating oil, and to maintain lubrication.
As another means, attempts have been made to improve the viscosity index using an expensive synthetic base oil, but it has been applied only to limited applications.
Recently, a high-viscosity index lubricant base oil having a viscosity index of around 140 has been produced by hydroisomerization dewaxing of the wax obtained by solvent extraction, and it has been proposed to be used as a lubricant for internal combustion engines. (See Patent Document 2).

JP-A-54-70305 JP 2004-137317 A

  The present invention has been made under such circumstances, and an object thereof is to provide a lubricating base oil having a high viscosity index and excellent low-temperature fluidity, and a method for producing the same. In addition, the present invention does not cause a decrease in viscosity even when subjected to mechanical shearing or thermal shearing, and retains the original viscosity characteristics over a long period of time even under thermal load conditions. It is an object of the present invention to provide a lubricating oil composition that prevents malfunction or malfunction of a machine due to an increase in viscosity. Furthermore, an object of the present invention is to provide a lubricating oil composition having a high viscosity index, high shear stability, high oxidation stability, and high flash point, and having a low density and advantageous for energy saving. is there.

As a result of intensive studies to achieve the above object, the present inventors have processed a specific wax fraction in a process including an isomerization dewaxing process and a hydrofinishing process, thereby providing a lubricating base oil. As a result, it was found that a base oil suitable for the purpose can be obtained. Moreover, it discovered that the lubricating oil composition which has high shear stability and high oxidation stability was obtained by selecting and mix | blending an appropriate lubricating oil additive further using this base oil. The present invention has been completed based on such findings.
That is, the gist of the present invention is as follows.
1. A hydrocarbon-based lubricating base oil having a viscosity index of 130 or more, a paraffin content (% C _P ) by ring analysis of 90% or more, and a CCS viscosity at −35 ° C. of 3,000 mPa · s. A lubricating base oil characterized by:
2. 2. The lubricating base oil according to 1 above, wherein the CCS viscosity at −35 ° C. is 2,200 mPa · s or less,
3. The lubricating base oil according to 1 or 2, wherein the viscosity index is 140 or more,
4. Any one of the above 1-3, wherein the kinematic viscosity at 100 ° C. is in the range of ² to 10 mm ² / s, the 5% distillation temperature in the distillation test is 380 ° C. or more, and the Noack value is 12% by mass or less. Lubricating base oil as described in
5. The lubricating base oil according to 4, wherein the kinematic viscosity at 100 ° C. is in the range of 3 to 6 mm ² / s,
6). Naphthene (% C _n) is a lubricating base oil according to any one of the 1 to 5 7% or less by ring analysis,
7). The lubricating base oil according to any one of 1 to 6, wherein the sulfur content is 30 mass ppm or less,
8. The lubricating oil group according to any one of 1 to 7 above, wherein an RBOT value (150 ° C.) is 480 minutes or more when 0.5 mass% of 2,6-di-t-butyl-p-cresol is added. oil,
9. The lubricating oil base according to any one of 1 to 8 above, wherein a wax fraction having a viscosity index of 180 or more is treated in the order of an isomerization dewaxing step, a vacuum distillation step, a hydrofinishing step, and a vacuum distillation step. Oil production method,
10. A lubricating oil composition comprising the lubricating base oil according to any one of 1 to 8,
11. The lubricating oil composition as described in 10 above, wherein a polymethacrylate having an average molecular weight of 40,000 or less is blended as a viscosity index improver,
12 The lubricating oil composition as described in 10 or 11 above, wherein a phenol-based and / or amine-based oxidation stabilizer, an ashless rust inhibitor, and a pour point depressant are blended,
13. The lubricating oil composition according to 10 or 11, wherein the lubricating oil composition is a lubricating oil composition for automatic transmissions, a lubricating oil composition for continuously variable transmissions, or a hydraulic fluid composition,
14 13. The lubricating oil composition as described in 12 above, wherein the lubricating oil composition is a hydraulic fluid composition.
Is to provide.

  According to the present invention, it is possible to provide a lubricating base oil having a high viscosity index and excellent low temperature fluidity and a method for producing the same. Further, according to the present invention, a lubricating oil composition having a high viscosity index, high shear stability, and high oxidation stability can be obtained. Further, according to the present invention, it is possible to provide a lubricating oil composition having a high viscosity index, high shear stability, high oxidation stability, and a high flash point, and having a low density and advantageous for energy saving. Accordingly, the lubricating oil composition of the present invention includes automotive engine oil, power steering oil, automatic transmission oil (ATF), continuously variable transmission oil (CVTF), hydraulic fluid, turbine oil, compressor oil, machine tool lubricating oil. It can be widely applied to cutting oil, gear oil, fluid bearing oil, rolling bearing oil, and the like.

The lubricating base oil of the present invention is a hydrocarbon-based lubricating base oil having a viscosity index of 130 or more, a paraffin content (% C _P ) by ring analysis of 90% or more, and −35 ° C. The CCS viscosity at 3,000 mPa · s or less.
If the viscosity index is less than 130, the low temperature fluidity may decrease. If the viscosity index is less than 130, the CCS viscosity at −35 ° C. may exceed 3,000 mPa · s. The preferred viscosity index is 140 or more, more preferably 150 or more, particularly 160 or more. The above viscosity index is measured according to JIS K 2283.
The paraffin content (% C _P ) by ring analysis is 90% or more. When% _CP is less than 90%, the oxidation stability may be lowered. Note that the% C _P is a value measured in accordance with ASTM D-3238.
Further, the CCS viscosity at −35 ° C. (cold cranking simulator viscosity by SAE) is 3,000 mPa · s or less. When the CCS viscosity at −35 ° C. exceeds 3,000 mPa · s, the low-temperature fluidity is deteriorated, and there is a risk that the engine startability at a low temperature is deteriorated. The CCS viscosity at −35 ° C. is preferably 2,200 mPa · s or less, particularly 2,100 mPa · s or less. In addition, said CCS viscosity is measured according to JISK2010.

Further, the lubricating base oil of the present invention preferably has the following properties.
The kinematic viscosity at 100 ° C. is preferably in the range of ² to 10 mm ² / s. Even at the scope of 3 to 8 mm ² / s, in particular about 3 to 6 mm ² / s. This kinematic viscosity is measured according to JIS K 2283.
The 5% distillation temperature in the distillation test is preferably 380 ° C. or higher. When the 5% distillation temperature is 380 ° C. or higher, the evaporation resistance is improved and the oil consumption can be reduced. More preferably, it is the range of 385-500 degreeC. The 5% distillation temperature in the above distillation test was measured according to JIS K 2254 (gas chromatographic method).

The Noack value (250 ° C.) is preferably 12% by mass or less. When the content is 12% by mass or less, the evaporation resistance is remarkably improved. More preferably, it is 10 mass% or less. The Noack value is an index indicating evaporability and is measured according to ASTM D-5800.
Moreover, as oxidation stability, the RBOT value (150 ° C.) is 480 or more in a rotary cylinder oxidation test (RBOT test) when 0.5 mass% of 2,6-di-t-butyl-p-cresol is added. It is preferable. If this RBOT value is 480 minutes or more, the oxidation life can be significantly extended. More preferably, the RBOT value is 500 minutes or more. The RBOT value is measured according to JIS K 2514.
The naphthene content (% C _n ) by ring analysis is preferably 7% or less, more preferably 3% or less. % C If _n is less than 7%, it is possible to obtain a good oxidation stability.

The sulfur content is preferably 30 ppm by mass or less, more preferably 20 ppm by mass or less, and particularly preferably 10 ppm by mass or less. If the sulfur content is 30 mass ppm or less, there is no possibility of causing corrosion.
In addition, the flash point usually varies depending on the (dynamic) viscosity of the base oil, but the lubricating base oil of the present invention has a higher flash point than conventionally known base oils. For example, in the case of a kinematic viscosity equivalent to 150 neutral, the flash point of the lubricating base oil of the present invention is preferably 240 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 260 ° C. or higher.
Further, the density varies depending on the (dynamic) viscosity of the base oil as in the case of the flash point, but the lubricating base oil of the present invention has a lower density than the conventionally known base oil. For example, speaking in the case of kinematic viscosity of 150 neutral equivalent, the density of the lubricating base oils of the present invention, 0.85 g / cm ³ or less, further 0.84 g / cm ³ or less, in particular 0.83 g / cm ³ or less Is preferred.

The lubricating base oil of the present invention having the above properties can satisfy the API (American Petroleum Institute) Group III standard.
The lubricating base oil can be used in combination with other lubricating base oils and various additives depending on the purpose, including the use of engine oil, ATF, and hydraulic fluid. That is, the lubricating base oil of the present invention can be used as a lubricating oil by itself, but it is usually suitable for each application by blending other lubricating base oils and various additives depending on the purpose. It should be used as a lubricating oil.

Next, a method for producing the lubricating base oil will be described.
In the present invention, the method for producing a lubricating base oil is not particularly limited. Preferably, a wax having a viscosity index of 180 or more is converted into a (a) isomerization dewaxing step, (b) a vacuum distillation step, as follows: It can manufacture by processing in order of (c) hydrofinishing process and (d) vacuum distillation process.
(A) Isomerization dewaxing step Wax having a viscosity index of 180 or more is used as a raw material. Furthermore, it is preferable that the kinematic viscosity at 100 ° C. is 4 to ²⁰ mm ² / s and the 10% distillation temperature in the distillation test is 380 ° C. or higher. Specifically, a wax fraction obtained by dewaxing a bottom oil obtained by hydrocracking a vacuum gas oil, a product obtained by Fischer-Tropsch synthesis, or the like can be used.
This isomerization dewaxing is performed by performing a hydrogenation treatment in the presence of a hydroisomerization catalyst in which a noble metal such as Pt or Pd is supported on a support such as SAPO (silica aluminophosphate) or zeolite.
About hydrogen partial pressure, it is 10 MPa or more normally, Preferably it is 13-22 MPa, More preferably, it is 15-21 MPa. About reaction temperature, it is 250-500 degreeC normally, Preferably it is 280-480 degreeC, More preferably, it is 300-450 degreeC. About liquid hourly space velocity (LHSV), it is 0.1-10 hr < ^-1 > normally, Preferably it is 0.3-8 hr < ^-1 >, More preferably, it is 0.5-2 hr < ^-1 >. The ratio of feed hydrogen gas, the supply Oil 1 kiloliter usually 100～1,000Nm ^3, preferably 200 to 800 nm ^3, more preferably 250~650Nm ^3.

(B) Vacuum distillation step The light oil fraction is removed by vacuum distillation of the product oil from the previous step so that the flash point is 200 to 210 ° C.
(C) Hydrofinishing step This hydrofinishing is carried out by using Ni / Mo, Co / Mo, Ni, etc. on the amorphous oil such as silica / alumina and alumina and the crystalline carrier such as zeolite. This is carried out by performing a hydrogenation treatment in the presence of a hydrogenation catalyst carrying a metal oxide such as / W or a noble metal such as Pt or Pd.
About hydrogen partial pressure, it is 10 MPa or more normally, Preferably it is 13-22 MPa, More preferably, it is 15-21 MPa. About reaction temperature, it is 200-350 degreeC normally, Preferably it is 250-330 degreeC, More preferably, it is 280-320 degreeC. About liquid hourly space velocity (LHSV), it is 0.1-10 hr < ^-1 > normally, Preferably it is 0.2-5 hr < ^-1 >, More preferably, it is 0.4-2 hr < ^-1 >. The ratio of feed hydrogen gas, the supply oil 1 kl, usually 100～1,000Nm ^3, preferably 200 to 800 nm ^3, more preferably 250~650Nm ^3.
(D) Vacuum distillation step The oil produced in the previous step is adjusted by vacuum distillation so that the kinematic viscosity at 100 ° C. is 2.0 to 10.0 mm ² / s.
Through the above four steps, a lubricating base oil having preferred properties in the present invention can be produced efficiently and at low cost.

The lubricating oil composition in the present invention is a lubricating oil composition containing the lubricating base oil. This lubricating oil can provide a lubricating oil composition having the characteristics of the lubricating base oil, that is, having a high viscosity index, low temperature fluidity, and high oxidation stability. In addition, an energy-saving lubricating oil having a lower density than that of a known lubricating base oil can be obtained.
In the lubricating oil composition of the present invention, the lubricating base oil of the present invention is used as the lubricating base oil, but other lubricating base oils may be mixed and used depending on the purpose. In that case, in the lubricating base oil of the lubricating oil composition, the content of the lubricating base oil of the present invention is preferably 60% by mass or more based on the total amount of the lubricating base oil, and more preferably 80% by mass or more. In particular, it is preferably 90% by mass or more. When the lubricating base oil of the present invention is contained in an amount of 60% by mass or more of the entire lubricating base oil, a composition that makes full use of the characteristics of the lubricating base oil of the present invention can be obtained.

The lubricant base oil other than the lubricant base oil of the present invention is not particularly limited, and a conventionally used mineral oil or synthetic oil can be used, and may be appropriately selected according to the use.
Examples of mineral oils include paraffinic mineral oils, naphthenic mineral oils, intermediate base mineral oils, and specific examples include light neutral oils, medium neutral oils, heavy neutral oils, bright stocks by solvent refining or hydrogenation refining. And so on. On the other hand, as synthetic oil, for example, poly-α-olefin, α-olefin copolymer, polybutene, alkylbenzene, polyol ester, dibasic acid ester, polyhydric alcohol ester, polyoxyalkylene glycol, polyoxyalkylene glycol ester, polyoxyalkylene Examples include glycol ethers and cycloalkane compounds.

An example of a specific embodiment of the lubricating oil composition of the present invention includes a lubricating oil composition in which a polymethacrylate having an average molecular weight of 40,000 or less is blended as a viscosity index improver with the lubricating base oil. Since this lubricating oil composition has both a particularly high viscosity index and a high degree of shear stability, this lubricating oil composition is effective as any lubricating oil composition such as automobile lubricating oil, and particularly suitable as ATF, CVTF, and hydraulic fluid. is there.
The average molecular weight of the polymethacrylate is preferably 10,000 to 40,000, more preferably 16,000 to 30,000. In addition, the average molecular weight here is a weight average molecular weight. Moreover, the blending amount of the polymethacrylate is preferably 0.2 to 15% by mass, preferably 0.5 to 10% by mass, and more preferably 1 to 5% by mass based on the total amount of the composition. When the blending amount of the polymethacrylate is 0.2 to 15% by mass based on the total amount of the composition, an effect of further increasing the viscosity index and maintaining high shear stability can be obtained. Regarding the shear stability, it is preferable that the viscosity decrease in the KRL shear test DIN 51650 (CECL45) is 5% or less, particularly 3% or less.
If desired, the lubricating oil composition may contain conventional ATF or CVTF additives, commercially available additive packages, or other general additives as described below.
The lubricating oil composition of the present invention has almost no decrease in viscosity even when subjected to mechanical shearing or thermal shearing, and retains the original viscosity characteristics over a long period of time even under heat load conditions. It is possible to prevent malfunction and malfunction of the machine due to poor lubrication and increased viscosity.

As an example of another specific embodiment of the lubricating oil composition in the present invention, a phenol-based and / or amine-based oxidation stabilizer, an ashless rust inhibitor, and a pour point depressant are added to the lubricating base oil. A blended lubricating oil composition may be mentioned.
Such a lubricating oil composition can be suitably used particularly for industrial lubricating oils such as hydraulic fluids, turbine oils, compressor oils, machine tool lubricants, gear oils, fluid bearing oils and rolling bearing oils. .

Examples of the phenol-based compound among the oxidation stabilizers include 2,6-di-t-butylphenol; 2,6-di-t-butyl-p-cresol; 4,4′-methylenebis- (2,6- Di-t-butylphenol); 4,4'-bis (2-methyl-6-t-butylphenol); 2,2'-methylenebis (4-ethyl-6-t-butylphenol); 2,2'-methylenebis ( 4-methyl-6-tert-butylphenol); 4,4′-butylidenebis (3-methyl-6-tert-butylphenol); 4,4′-isopropylidenebis (2,6-di-tert-butylphenol); 2 2,2′-methylenebis (4-methyl-6-tert-nonylphenol); 2,2′-isobutylenebis (4,6-dimethylphenol); 2,2′-methylenebis (4-methyl-6-cyclohexene) 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; Di-t-amyl-p-cresol; 2,6-di-t-butyl-4- (N, N'-dimethylaminomethylphenol);4,4'-thiobis (2-methyl-6-t-butylphenol) 4,4′-thiobis (3-methyl-6-tert-butylphenol); 2,2′-thiobis (4-methyl-6-tert-butylphenol); bis (3-methyl-4-hydroxy-5-) t-butylbenzyl) sulfide; bis (3,5-di-t-butyl-4-hydroxybenzyl) sulfide; n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate 2,2'-thio [diethyl - bis-3- (3,5-di -t- butyl-4-hydroxyphenyl) propionate] and the like. Among these, bisphenol-based and ester group-containing phenol-based ones are particularly preferable.
Examples of the amine compound include alkylated diphenylamine and phenyl-α-naphthylamine.
One of these oxidation stabilizers may be used alone, or two or more thereof may be used in combination. The blending amount of the oxidation stabilizer is preferably 0.01 to 5.0% by mass, more preferably 0.1 to 3.0% by mass based on the total amount of the composition.

Examples of the ashless rust preventive include alkyl succinic acid, alkenyl succinic acid, and partial esters thereof. In this invention, these may be used individually by 1 type and may be used in combination of 2 or more types. The amount of the ashless rust inhibitor is preferably 0.01 to 1.0 mass%, more preferably 0.01 to 0.5 mass%, based on the total amount of the composition.
Examples of the pour point depressant include polyalkyl methacrylate, polybutene, polyalkyl styrene, polyvinyl acetate, polyalkyl acrylate, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate copolymer, chlorinated polyethylene, alkenyl succinic acid. Examples include amide compounds. One of these pour point depressants may be used alone, or two or more thereof may be used in combination. The blending amount of the pour point depressant is preferably 0.1 to 2.0% by mass and more preferably 0.1 to 1.0% by mass based on the total amount of the composition.

Thus, the lubricating oil composition in which the lubricating base oil is blended with an oxidation stabilizer, an ashless rust inhibitor, and a pour point depressant has the following advantages.
Since the lubricating oil composition of the present invention provides a very high viscosity index as compared with the case of using a normal secondary hydrogenated base oil, it is not necessary to add a viscosity index improver or it may be added. A small amount is sufficient. Therefore, good shear stability can be obtained. This effect is particularly remarkable when a lubricating base oil having a viscosity index of 150 or higher is used.
As for the flash point, ISO VG32 grade (40 ° C. kinematic viscosity; 28.8 to 35.2) having a temperature of 250 ° C. or higher is obtained. This is a higher flash point and flame retardant than a lubricating oil using an ordinary secondary hydrogenated base oil.
Furthermore, it has higher oxidative stability than when a normal secondary hydrogenated base oil is used. In addition, because of the low density, the pressure loss is small and it is excellent in terms of energy saving.
Further, the pour point is −35 ° C. or lower, and the low temperature characteristics are excellent.
Furthermore, the acid value (indicator method) is 0.12 mg KOH / g or less, and the color (JIS K 2580) is 1.0 or less.
Such a lubricating oil composition can be suitably used as any lubricating oil composition, in particular, various industrial lubricating oils, particularly hydraulic hydraulic oils.

Furthermore, additives other than those described above can be blended and used in the lubricating oil composition of the present invention within a range that does not impair the object of the present invention. For example, detergent dispersants, antiwear agents, extreme pressure agents, metal deactivators, friction reducers, viscosity index improvers, anti-emulsifiers, antifoaming agents, and the like can be blended.
Examples of detergent dispersants include metal detergents such as alkaline earth metal sulfonate, alkaline earth metal phenate, alkaline earth metal salicylate, alkaline earth metal phosphonate; alkenyl succinimide, benzylamine, alkyl polyamine, alkenyl succinate Examples include ashless dispersants such as acid esters.
Examples of the antiwear agent include organic molybdenum compounds such as molybdenum sulfide oxydithiophosphate (MoDTP) and molybdenum sulfide oxydithiocarbamate (MoDTC), organic zinc compounds such as zinc dithiophosphate (ZnDTP) and zinc dithiocarbamate (ZnDTC), Examples thereof include organic boron compounds such as alkyl mercaptyl borate, solid lubricants such as graphite, molybdenum disulfide, antimony sulfide, boron compounds, and polytetrafluoroethylene.

  As the extreme pressure agent, a sulfur-based extreme pressure agent or a phosphorus-based extreme pressure agent can be used. Examples of sulfur-based extreme pressure agents include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, polysulfides, sulfurized olefins, thiocarbamates, thioterpenes, and dialkylthiodipropionates. Of these, sulfurized fats and oils, polysulfide and sulfurized olefins are preferred. Examples of the phosphorous extreme pressure agent include phosphoric acid esters, (mono, di, tri) thiophosphoric acid esters, acidic phosphoric acid ester amine salts, (mono, di) thiophosphoric acid ester amine salts, phosphorous acid esters, ( And mono, di, tri) thiophosphite.

Examples of the metal deactivator include benzotriazole, thiadiazole, alkenyl succinate and derivatives thereof.
Examples of the friction reducing agent include aliphatic alcohols, fatty acids, fatty acid esters, aliphatic amines, aliphatic amine salts, and aliphatic amides.
As the viscosity index improver, in addition to the above, polyisobutylene, ethylene-propylene copolymer, styrene-isoprene copolymer, styrene-butadiene hydrogenated copolymer, and the like can be used in combination.
Examples of demulsifiers include anion activators such as castor oil sulfate salt, petroleum sulfonate, and aerosol OT type; cation activators such as quaternary ammonium salt and imidazoline type; and nonionic activators such as alkylene oxide. Can be mentioned.
Examples of the antifoaming agent include dimethylpolysiloxane and polyacrylate.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Example 1
Using a hydroisomerization catalyst (Pt / zeolite) as a raw material (raw material 1, Table 1), wax 1 obtained by dewaxing bottom oil obtained by hydrocracking vacuum gas oil, reaction temperature The isomerization dewaxing was performed under the conditions of 330 ° C., hydrogen partial pressure 16 MPa, hydrogen / oil ratio 800 Nm ³ / kL, LHSV 1.0 hr ⁻¹ . The resulting product oil was subjected to vacuum distillation to remove light components so that the flash point was 200 to 210 ° C. Using this Ni, W / alumina catalyst, the product oil from which this light component has been removed is subjected to a reaction temperature of 290 ° C., a hydrogen partial pressure of 20 MPa, a hydrogen / oil ratio of 1,000 Nm ³ / kL, and an LHSV of 0.5 hr ⁻¹ . Hydrofinishing was performed. The obtained product oil was adjusted to a kinematic viscosity of 4.0 to 5.0 mm ² / s at 100 ° C. by distillation under reduced pressure to obtain a base oil 1. The obtained base oil 1 had a very high paraffin content (% C _P ) of 97.0%. An RBOT oxidation test was conducted by adding 0.5% by mass of an oxidation stabilizer DBPC (2,6-di-t-butyl-p-cresol) to this base oil. The properties of the base oil 1 are shown in Table 2.
Example 2
Base oil 2 was obtained by performing hydroisomerization dewaxing, vacuum distillation, hydrofinishing, and vacuum distillation under the same conditions as in Example 1 using wax 2 having a different viscosity index as raw material (raw material 2, Table 1). An RBOT oxidation test was performed on this base oil to which 0.5% by mass of an oxidation stabilizer DBPC was added. The properties of the base oil 1 are shown in Table 2.

Comparative Example 1
Hydrowaxing dewaxing under the same conditions as in Example 1 using a waxy oil mixed with wax instead of wax and adjusting the viscosity index as a raw material (raw material 3, Table 1), followed by the same procedure as in Example 1 Distillation under reduced pressure was followed by hydrofinishing under conditions of a reaction temperature of 250 ° C., a hydrogen partial pressure of 20 MPa, a hydrogen / oil ratio of 1,000 Nm ³ / kL, and LHSV of 1.0 hr ⁻¹ . Thereafter, distillation under reduced pressure was performed under the same conditions as in Example 1 to obtain a comparative base oil I. An RBOT oxidation test was performed on this base oil to which 0.5% by mass of an oxidation stabilizer DBPC was added. The properties of Comparative Base Oil I are shown in Table 2.

Examples 3-7 and Comparative Examples 2-6
According to the following, a lubricating oil composition for ATF / CVTF was prepared and evaluated.
(1) Base oil Using raw material 1 as the raw material, hydroisomerization dewaxing, vacuum distillation, hydrofinishing, and vacuum distillation were performed under the same conditions as in Example 1, and base oil 3 (70 neutral, hereinafter abbreviated as “70N”). ), Base oil 4 (100 neutral, hereinafter abbreviated as “100 N”) and base oil 5 (150 neutral, hereinafter abbreviated as “150 N”). For comparison, conventional comparative mineral base oils II to IV (70N, 100N and 150N, respectively) and comparative base oil V (poly-α-olefin, hereinafter abbreviated as “PAO”) were prepared. Table 3 shows the properties of these base oils.

(2) Preparation and evaluation test of lubricating oil composition Using base oils 3 to 5 and comparative base oils II to V as described above, additives were blended according to the formulations shown in Tables 4 and 5 and lubrication for ATF / CVTF An oil composition was prepared. In Examples 5 and 7 and Comparative Examples 3, 5, and 6, a predetermined amount of polymethacrylate (PMA) having an average molecular weight of 30,000 was blended. These compositions were measured for viscosity characteristics, viscosity index, low temperature viscosity, KRL shear viscosity reduction, and viscosity change and oxidation increase as oxidation stability. The results are shown in Tables 4 and 5.

(note)
* 1 Viscosity characteristics: Conforms to JIS K2283.
* 2 Viscosity index: Conforms to JIS K2283.
* 3 Low temperature viscosity: Brookfield viscosity at -40 ° C.
* 4 KRL shear viscosity reduction: Shown as a percentage (%) of viscosity reduction relative to its initial value after being subjected to KRL shear test DIN 51350 (CECL45). The smaller the value, the better.
* 5 Oxidation stability: Measured according to JIS K2514 at 150 ° C. for 480 hours.
** ATF / CVTF additives: metal deactivators, oxidation stabilizers, detergents, dispersants, antiwear agents, antifoaming agents, etc.

(Note) Same as footnote in Table 4.
In the above, Example 3 using the base oil 3 has a high viscosity index, and the viscosity decrease due to mechanical shearing by the KRL test is extremely small. In addition, there is little change in viscosity and increase in acidic components in the oil (acid value increase) due to the oxidation stability test exposed at 150 ° C. for 480 hours. In contrast, Comparative Example 2 using a conventional base oil having a high viscosity index has a low viscosity index of 122, and the viscosity change and acid value increase in the oxidation stability test are considerably larger than those of Example 3 (increased viscosity increase). Is 3.8 times that of Example 3, and the acid value increase is 5.2 times).
Example 4 using the base oil 4 is an extremely suitable example as a lubricating oil for ATF / CVTF, and has a high viscosity index and excellent mechanical stability, thermal and oxidative stability. In contrast, Comparative Example 3 using a conventional base oil having a high viscosity index has a low viscosity index and a low-temperature viscosity of 50,000 mPa · S or more, and is 20,000 mPa · S, which is a normal ATF standard. The following cannot be satisfied.
Example 5 is an example of a general-purpose ATF / CVTF lubricating oil, in which PMA is blended with a mixed oil of the base oil 3 and the base oil 5. It has a high viscosity index and is excellent in mechanical shear and thermal / oxidative stability. On the other hand, Comparative Example 4 is an example of a composition having the same viscosity characteristics using a conventional base oil. However, since it does not have a sufficiently high viscosity index, it loses fluidity (solidifies) at a low temperature, and its heat / oxidation stability is significantly inferior to that of Example 5.

Example 6 has a sufficiently high viscosity index and is excellent in mechanical shear and thermal / oxidative stability. On the other hand, the comparative example 5 is an example using the conventional high viscosity index base oil, and in order to provide the viscosity characteristic comparable as the said Example 5, 10 mass% of PMA is mix | blended. For this reason, the mechanical shear is large, the viscosity is reduced by 10% or more, and the thermal / oxidation stability is greatly deteriorated as compared with Example 6.
Example 7 is an example in which 2% by mass of PMA having an average molecular weight of 30,000 is blended with the base oil 4, and the viscosity index is 180 or higher, and the mechanical shear is suppressed to 3% or less at the same time. On the other hand, Comparative Example 6 is an example using polyalphaolefin (PAO) as a synthetic base oil. PAO has a high viscosity index, but in order to obtain a viscosity characteristic comparable to that of Example 7, it requires the blending of PMA, and as a result, the viscosity drop due to mechanical shear is as large as 10%.
As described above, it can be seen that all of the base oils 3 to 5 in the present invention are suitable as a lubricating oil composition having a high viscosity index and being hardly subjected to mechanical shearing and having excellent thermal and oxidation stability.

Example 8
(1) Base oil The base oil 6 was obtained by performing hydroisomerization dewaxing, vacuum distillation, hydrofinishing, and vacuum distillation under the same conditions as in Example 1 using the raw material 1 shown in Table 1. The properties of the base oil 6 are shown in Table 6. For comparison, the properties of conventional mineral base oil (comparative base oil VI) and PAO (comparative base oil VII) as a synthetic base oil are also shown.
When the base oil 6 is compared with the conventional comparative base oils VI and VII, it can be seen that it has a high viscosity index, a high flash point, and a low density.

(2) Preparation of Lubricating Oil Composition Using the base oil 6 described above, an additive was added according to the formulation shown in Table 7 to prepare a hydraulic fluid composition of Example 8.
Further, as Comparative Example 7, a mixed oil of (i) secondary hydrorefined mineral oil (comparative base oil VI) and (ii) secondary hydroisomerization dewaxed mineral oil (comparative base oil VIII) was used. The hydraulic fluid having a normal wear-resistant type and a high viscosity index was prepared by blending the additive according to the following formula.
Table 8 shows the results obtained by measuring the properties of the compositions of Example 8 and Comparative Example 7.

(note)
* 6 Brookfield viscosity at -30 ° C.
* 7 Shear stability (ultrasonic wave): Measured under the conditions of shear stability test using ultrasonic waves, frequency 10 KHz, amplitude 28 μ, time 30 minutes, oil amount 30 mL.
As a result, the composition of Example 8 using the base oil 6 according to the present invention has a viscosity index of 160 or higher, a flash point of 260 ° C. or higher, high shear stability, and high oxidation stability. Moreover, it can be seen that the hydraulic fluid is advantageous for energy saving because of its low density.

The lubricating base oil in the present invention is a base oil having a high viscosity index and excellent low-temperature fluidity, and the lubricating oil composition of the present invention containing this base oil includes an engine oil for automobiles and an automatic transmission. It can be applied to machine oil, continuously variable transmission oil, hydraulic fluid, turbine oil, compressor oil, machine tool lubricant, cutting oil, gear oil, fluid bearing oil, rolling bearing oil, and the like.

Claims (14)

A hydrocarbon-based lubricating base oil having a viscosity index of 130 or more, a paraffin content (% C _P ) by ring analysis of 90% or more, and a CCS viscosity at −35 ° C. of 3,000 mPa · s. Lubricating base oil characterized by: The lubricating base oil according to claim 1, wherein the CCS viscosity at -35 ° C is 2,200 mPa · s or less. The lubricating base oil according to claim 1 or 2, having a viscosity index of 140 or more. The kinematic viscosity at 100 ° C is in the range of ² to 10 mm ² / s, the 5% distillation temperature in the distillation test is 380 ° C or higher, and the Noack value is 12 mass% or lower. The lubricating base oil described. The lubricating base oil according to claim 4, wherein the kinematic viscosity at 100 ° C is in the range of 3 to 6 mm ² / s. Naphthene content by ring analysis (% C _n) is a lubricating base oil according to any one of claims 1 to 5, 7% or less. The lubricating base oil according to any one of claims 1 to 6, wherein the sulfur content is 30 mass ppm or less. The lubricating base oil according to any one of claims 1 to 7, which has an RBOT value (150 ° C) of 480 minutes or more when 0.5 mass% of 2,6-di-t-butyl-p-cresol is added. . The lubricating oil according to any one of claims 1 to 8, wherein a wax fraction having a viscosity index of 180 or more is processed in the order of an isomerization dewaxing step, a vacuum distillation step, a hydrofinishing step, and a vacuum distillation step. Manufacturing method of base oil. The lubricating oil composition containing the lubricating base oil in any one of Claims 1-8. The lubricating oil composition according to claim 10, wherein polymethacrylate having an average molecular weight of 40,000 or less is blended as a viscosity index improver. The lubricating oil composition according to claim 10 or 11, wherein a phenol-based and / or amine-based oxidation stabilizer, an ashless rust inhibitor, and a pour point depressant are blended. The lubricating oil composition according to claim 10 or 11, wherein the lubricating oil composition is a lubricating oil composition for an automatic transmission, a lubricating oil composition for a continuously variable transmission, or a hydraulic fluid composition. The lubricating oil composition according to claim 12, wherein the lubricating oil composition is a hydraulic fluid composition.