JP5185489B2 - Base oil for lubricating oil comprising decene oligomer hydride, lubricating oil composition, and method for producing decene oligomer hydride - Google Patents

Description

  The present invention relates to a base oil for lubricating oil, a lubricating oil composition, and a process for producing a decene oligomer hydride, and more particularly, a base oil for lubricating oil having a low viscosity, low temperature fluidity and high flash point, a lubricating oil composition, and The present invention relates to an effective method for producing a decene oligomer hydride used in the base oil for lubricating oil.

In recent years, machine parts such as copiers, fax machines, toys and other gears, bearing shafts, etc. are made of polycarbonate resin, ABS resin, polystyrene resin, polycarbonate-ABS resin, etc. because of their mechanical strength, lightness and low price. Resin moldings are widely used and used alone or in combination with metal mechanical parts. For rust prevention and lubrication of these machine parts, rust preventive lubricating compositions in which a rust inhibitor is added to an ester compound, a diester compound, or a lubricant mainly composed of mineral oil have been used.
However, a rust preventive lubricating composition in which a rust preventive agent is added to the above ester compound or diester compound has recently been given an effect called chemical attack on plastic products, such as plastic gears, bearing shafts, etc. Have been found to cause damage and cracks. For this reason, it has been proposed to use a saturated aliphatic monocarboxylic acid diester of an aliphatic dihydric alcohol as the base oil, or to blend a specific carbonate ester or an oxyfatty acid oligomer with a base oil composed of a hydrocarbon such as polyolefin. (See, for example, Patent Documents 1, 2, and 3).

By the way, as an oligomerization of decene, an acid catalyst (BF ₃ or the like) has been used so far, and a high-viscosity decene trimer hydride has been produced (see, for example, Patent Document 4). . Recently, dewaxing lubricants by decene oligomerization have appeared, but even if the kinematic viscosities can be combined, a low temperature fluidity lubricant with a high flash point can be obtained with the same kinematic viscosity. (For example, refer to Patent Document 5).
In addition, as rust preventive lubricating compositions for plastic moldings, proposed are synthetic hydrocarbon oils such as decene oligomers, blended with rust preventive additives, and grease compositions blended with thickeners and extreme pressure agents. (For example, see Patent Documents 6 and 7).
As a method for producing a decene oligomer, it is known that a decene oligomer having a number average molecular weight of 500 to 200,000 is produced using a metallocene catalyst, followed by hydrogenation if necessary, and used as a base oil for lubricating oil ( For example, see Patent Document 8).

JP 2003-321691 A JP 10-36870 A JP-A-11-199885 Japanese National Patent Publication No. 10-504326 Japanese translation of PCT publication No. 2002-502436 Japanese Patent Application Laid-Open No. 2003-239954 JP 2002-69474 A Special Table 2002-518582

In particular, lubricating oils for information equipment and the like are required to have a low viscosity at a low temperature (40 ° C.), an excellent viscosity index and low temperature fluidity, a high boiling point and a high flash point. As described above, decene oligomers are used as base oils for lubricating oils, but lubricating oils having low viscosity at low temperatures have not been obtained. Further, if the base oil (synthetic hydrocarbon oil) is low viscosity at a low temperature, it can cope with an increase in viscosity due to the addition of a rust inhibitor and a viscosity index improver.
The present invention has been made in view of the above circumstances, and has a low viscosity at low temperature, an excellent viscosity index and low temperature fluidity, and a high flash point, a lubricating oil base oil, a lubricating oil composition, and a lubricating oil. An object of the present invention is to provide a method for producing a decentrimer hydride used in an oil base oil.

  As a result of intensive studies to solve the above problems, the present inventor has found that a decene oligomer hydride having specific physical properties is excellent as a base oil for lubricating oil, and this decene oligomer hydride uses a metallocene catalyst. After the oligomerization and the alkali treatment, the inventors found that it can be obtained by purifying by hydrogenation under specific conditions, and reached the present invention.

That is, the present invention
(1), (A) consisting of a decene oligomer hydride having a kinematic viscosity at 40 ° C. of 16 mm ² / s or less, (B) a flash point of 250 ° C. or more, and (C) a pour point of −50 ° C. or less. A base oil for lubricating oil in which 90% by mass or more of the oligomer hydride is a decent trimer hydride , and ( 2 ) a lubricating oil using the base oil for lubricating oil of (1) as the base oil A composition is provided.

  According to the present invention, a base oil for lubricating oil (synthetic hydrocarbon oil) having a low kinematic viscosity at 40 ° C. and a low-temperature fluidity having a high flash point can be obtained. Thus, if the synthetic hydrocarbon oil is low-temperature and low-viscosity, it can cope with the viscosity increase accompanying the addition of the rust inhibitor and viscosity index improver, so the base oil for lubricating oil of the present invention is a bearing oil, plastic molding It can be used for a rust preventive lubricating composition for textiles, a textile fiber finish (emulsifier composition) and the like.

First, the base oil for lubricating oil of the present invention has (A) a kinematic viscosity at 40 ° C. of 16 mm ² / s or less, (B) a flash point of 225 ° C. or more, and (C) a pour point of −50 ° C. or less. It consists of an oligomer hydride.
1-decene is used as a raw material for producing decene oligomer hydride. Patent Document 1 discloses that a poly-α-olefin (decene oligomer hydride) obtained by hydrotreating a polymer of 1-decene is excellent in high-temperature stability, but has a large increase in viscosity at low temperatures and low temperature. However, the decene oligomer hydride in the base oil for lubricating oil according to the present invention can be obtained by the method described later. It is manufactured, has a low viscosity at low temperature (flow resistance), and has low temperature fluidity.

Kinematic viscosity (A) at 40 ° C. of the lubricating base oil of the present invention is 16 mm ² / s or less, preferably 11 to 16 mM ² / s. If the kinematic viscosity at such a low temperature is small, it can be easily handled at the time of starting the bearing, etc., and if it is low in this way, it copes with the viscosity increase due to the addition of a rust inhibitor and viscosity index improver. it can.
In addition, the (B) flash point of the lubricating base oil of the present invention is 225 ° C. or higher, preferably 230 ° C. or higher. Since the base oil for lubricating oil of the present invention has a high flash point, it has excellent thermal stability and can withstand use in a severe environment at high temperatures. This flash point is measured by the COC method (JIS K 2265).
The (C) pour point of the base oil for lubricating oil of the present invention is −50 ° C. or lower. As described above, the base oil for lubricating oil of the present invention exhibits excellent lubricity over a long period of time in a wide temperature range with a low viscosity, and therefore, particularly as a sintered impregnated bearing or a fluid bearing, or at high temperature and high speed rotation. It can be suitably used as a base oil of grease sealed in a rolling bearing used.
In the base oil for lubricating oil of the present invention, it is preferable that 90% by mass or more of the decene oligomer hydride is a decent trimer hydride. Thus, by using a decent trimer hydride having a high concentration of decent trimer hydride and a high purity decent trimer hydride, a kinematic viscosity at a low temperature is reduced, and a base oil for lubricating oil having a high flash point and low temperature fluidity is obtained.

  The lubricating oil composition of the present invention is based on the decene oligomer hydride described above, and includes an antioxidant, extreme pressure agent, rust inhibitor, metal corrosion inhibitor, oiliness agent, viscosity index improver. In addition, one or two or more additives such as a pour point depressant and an adhesion improver are appropriately blended. The compounding quantity of these additives is 0.01-10 mass% normally with respect to the decene oligomer hydride of a base oil, respectively, Preferably it is 0.1-5 mass%.

Next, the manufacturing method of the decene oligomer hydride used for the base oil for lubricating oil of this invention is demonstrated.
First, the raw material decene in the step of oligomerizing the decene in step (a) is linear 1-decene, which is used alone or 40 mol% or less, particularly 20 mol based on the amount of 1-decene. % Of other linear C ₈ -C ₁₂ -1-alkene (at least one selected from 1-octene, 1-nonene, 1-undecene and 1-dodecene) Can be mixed and oligomerized. These 1-alkenes can be used as chemically pure (usually 99 to 99.9% by weight purity) or as industrial mixtures with a purity of usually 90 to 99% by weight. In so doing, the components remaining in the industrial mixture are usually approximately volatile, polymerizable or non-polymerizable components (eg unsaturated isomers, homologues or saturated hydrocarbons). The 1-alkenes used are generally substantially free of volatile components, in particular those which contain more volatile saturated or unsaturated hydrocarbons, especially those having less than 8 carbon atoms. It should be noted that “not containing substantially” means that the maximum possible ratio of such volatile components is less than 1% by mass, particularly less than 0.5% by mass.

In the step of oligomerizing decene (a), a complex containing a group 4 element of the periodic table and having a conjugated carbon 5-membered ring as a catalyst, that is, a metallocene complex is used, and an oxygen-containing organic compound is used as a promoter. Aluminum compounds are used.
In addition, even when triethylaluminum is used alone and oligomerization of high-temperature decene at about 160 ° C. is carried out, a decene oligomerized product is obtained, but the product is a dimer and almost no trimer is obtained.
As the Group 4 element of the periodic table in the metallocene complex, titanium, zirconium and hafnium are used, and zirconium is particularly preferable. As the complex having a conjugated carbon 5-membered ring, a complex having a substituted or unsubstituted cyclopentadienyl ligand is generally used.

As a metallocene complex, it can select from a conventionally well-known compound suitably and can be used. Examples of suitable metallocene complexes include bis (n-octadecylcyclopentadienyl) zirconium dichloride, bis (trimethylsilylcyclopentadienyl) zirconium dichloride, bis (tetrahydroindenyl) zirconium dichloride, bis [(t-butyldimethylsilyl ) Cyclopentadienyl] zirconium dichloride, bis (di-t-butylcyclopentadienyl) zirconium dichloride, (ethylidene-bisindenyl) zirconium dichloride, biscyclopentadienylzirconium dichloride, ethylidenebis (tetrahydroindenyl) zirconium dichloride and And bis [3,3 (2-methyl-benzindenyl)] dimethylsilanediylzirconium dichloride.
Such metallocene complexes can be synthesized by a simple known method (for example, the method described in Brauer (ed.): Handbuch der Praeparativen Anorganischen Chemie, Volume 2, 3rd edition, pages 1395 to 1397, Enke, Stuttgart 1978). Preference is given to a process starting from a suitably substituted lithium salt of cyclopentadienyl which is reacted with a transition metal halide.
Although it is advisable to use only one metallocene complex in the oligomerization reaction, a mixture of various metallocene complexes may be used.

On the other hand, examples of the oxygen-containing organoaluminum compound as a promoter include methylalumoxane, ethylalumoxane, and isobutylalumoxane. These may be used singly or in combination of two or more. If an organoaluminum compound such as sesquialuminum chloride is used instead of the oxygen-containing organoaluminum compound, the oligomerization reaction does not proceed.
The compounding ratio of the metallocene complex and the cocatalyst is an important factor that determines the production ratio of decene dimer, trimer and tetramer. Therefore, in the present invention, the molar ratio of metallocene complex: promoter is usually 1: 1000. To 1: 5, preferably 1: 200 to 1:
10.

The decene oligomer may be batched in a conventional reactor used for olefin oligomerization, but can be produced continuously and advantageously. A continuously operated stirring vessel is preferably used, and in some cases, a plurality of stirring vessels connected in series may be used.
In the oligomerization, a solvent is not necessarily required, and the oligomerization can be carried out in a suspension, a liquid monomer or an inert solvent. In the case of oligomerization in a solvent, liquid organic hydrocarbons such as benzene, ethylbenzene, toluene and the like are used. The oligomerization is preferably carried out in a reaction mixture in which liquid monomer is present in excess.
The conditions for oligomerization are a temperature of about 15 to 100 ° C. and a pressure of about atmospheric pressure to about 0.2 MPa.

As the post-treatment of the oligomerization reaction, water or alcohols are added, or a deactivation treatment is performed by a known method in which a halogen-free acid treatment is performed, and the oligomerization reaction is stopped.
The decene isomer of the side reaction product produced in the oligomerization stage may be removed after the oligomerization reaction by stripping, but after the hydrogenation treatment without separating the oligomerized product, the oligomer hydride is separated. It may be removed during the distillation.

Next, as the step of alkali-treating the oligomerized product in step (b), the catalyst component is removed using an alkaline aqueous solution or an alcohol-alkaline solution.
In the subsequent distillation step (d), when halogen and catalyst residues remain in the system, the physical properties of (A), (B) and (C) in the lubricating oil base oil of the present invention are obtained. It becomes difficult. Therefore, an alkali treatment is performed as a post-treatment of oligomerization so that halogen and catalyst residues can be completely removed.
Examples of the alkali used in the step (b) include sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and the like, and examples of the alcohol include methanol, ethanol and propanol. The pH of the alkaline aqueous solution is 9 or more, and the alkali treatment temperature is about 20 to 100 ° C.

Decene oligomers produced by metallocene catalysts have double bonds due to the mechanism of oligomerization, where the content of terminal vinylidene double bonds is particularly high. Since these double bonds are believed to hinder their use as engine oils or lubricants, they are converted to a saturated structure by a conventional hydrogenation process.
In the step of hydrotreating the oligomer in step (c), a known Ni or Co-based catalyst or a noble metal catalyst such as Pd or Pt is used. For example, diatomaceous earth supported Ni catalyst, cobalt trisacetylacetonate / organoaluminum catalyst, activated carbon supported palladium catalyst, alumina supported platinum catalyst and the like can be mentioned.
The hydrogenation conditions are a temperature of 200 ° C. or lower, typically 150 to 200 ° C. for Ni-based catalysts, and usually 50 to 150 ° C. for cobalt noble acetylacetonate / organoaluminum for noble metal catalysts such as Pd and Pt. In the case of a uniform reducing agent such as, the temperature is usually 20 to 100 ° C., and the hydrogen pressure is about normal pressure to 20 MPa.
Although the reaction temperature needs to be raised for the hydrogenation with Ni-based catalyst, if it exceeds 200 ° C, the purity of the hydride of the trimer is lowered, and various isomers are obtained, and the flash point is lowered. And Such a phenomenon is also observed with noble metal catalysts such as Pt and Pd, and the noble metal catalyst does not perform a hydrogenation reaction at a high temperature exceeding 150 ° C. Further, if the temperature of the hydrogenation reaction is lower than each lower limit temperature, the reaction rate becomes extremely slow.

The product of oligomerization contains decene dimer and decene tetramer in addition to decent trimer. These three kinds of compound groups each have a double bond positional isomer at the oligomerization stage, so that each of them becomes a plurality of compounds, but when hydrogenated, they become hydrides of decene dimer, trimer and tetramer, respectively. . When oligomerization and post-treatment are carried out by the above steps (a), (b) and (c), the decene oligomer hydride is usually 95% by mass or more in decent oligomer hydride and becomes almost a single compound. .
The step of distilling the hydrogenated oligomer in step (d) is to separate a decent trimer fraction suitable as the base oil for lubricating oil of the present invention from these decene oligomers. The temperature is about 180 to 450 ° C., and the pressure is about 0.01 to 100 kPa.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.
In addition, the physical property measurement of the decene oligomer hydride in each example was evaluated according to the following criteria.
(1) Kinematic viscosity and viscosity index at 40 ° C./100° C .: JIS K 2283
(2) Flash point: JIS K 2265
(3) Pour point: JIS K 2269

Example 1
(1) Decene oligomerization A three-necked flask with an internal volume of 5 liters was charged with 4 liters (21.4 mol) of decene monomer (Idemitsu Petrochemical Co., Ltd .: Linearlen 10) under an inert gas stream. Methylalumoxane (Al conversion: 40 mmol) dissolved in toluene was added in the same manner as biscyclopentadienylzirconium dichloride (complex mass 1168 mg: 4 mmol) dissolved in toluene. These mixtures were kept at 40 ° C. and stirred for 20 hours, and then 20 ml of methanol was added to stop the oligomerization reaction. Next, the reaction mixture was taken out of the autoclave, 4 liters of a 5 mol / liter sodium hydroxide aqueous solution was added thereto, the mixture was forcedly stirred at room temperature for 4 hours, and then a liquid separation operation was performed. The upper organic layer was removed, and unreacted decene and side reaction product decene isomers were removed by stripping.

(2) Hydrogenation of decene oligomer Cobalt trisacetylacetonate (catalyst weight: 3.0 g) in which 3 liters of decene oligomer produced in (1) was placed in an autoclave with an internal volume of 5 liters under nitrogen flow and dissolved in toluene And triisobutylaluminum diluted with toluene (30 mmol) were added. After the addition, the inside of the system was replaced with hydrogen twice, and then the temperature was raised. The hydrogen pressure was maintained at 0.9 MPa at a reaction temperature of 80 ° C. Hydrogenation proceeded immediately with exotherm, the temperature was lowered at 4 hours after the start of the reaction, and the reaction was stopped. Then, after depressurizing and taking out the contents, the reaction product was subjected to simple distillation to separate a fraction having a distillation temperature of 240 to 270 ° C. and a pressure of 530 Pa. The yield of the obtained decentrimer hydride is 120 ml, and the yield based on the raw material decene monomer is 3% by mass.
The results of measuring the physical properties of the obtained decentrimer hydride are shown in Table 1. Moreover, the result of having analyzed this decent trimer hydride with the gas chromatograph is shown in FIG. From this chart, it can be seen that the obtained decentrimer hydride is a highly pure, almost single compound.

Comparative Example 1
By the method of Example 1 of Patent Document 4, a decene monomer (Idemitsu Petrochemical Co., Ltd .: Linearene 10) was oligomerized using BF ₃ as a catalyst. The obtained reaction mixture was hydrogenated in the same manner as in (2) above, and then the reaction product was subjected to simple distillation. As in Example 1, a fraction having a distillation temperature of 240 to 270 ° C. and a pressure of 530 Pa was obtained. separated.
The results of measuring the physical properties of the obtained decentrimer hydride are shown in Table 1. Moreover, the result of having analyzed this decent trimer hydride with the gas chromatograph is shown in FIG. From this chart, it can be seen that the obtained decentrimer hydride is a mixture of a myriad of compounds.

  From Table 1 showing the results of measuring the kinematic viscosity, viscosity index, flash point and pour point of the decentrimer hydride produced in Example 1 and Comparative Example 1, the decentrimer hydride obtained in Example 1 is Compared to the decent trimer hydride obtained in Comparative Example 1, it is a lubricating oil having a low kinematic viscosity at a low temperature and a good viscosity index, and it has a low viscosity at a low temperature. It can be seen that the flash point is high and the low temperature fluidity is excellent.

The chart of the result of having analyzed the decent trimer hydride obtained in Example 1 with the gas chromatograph is shown. The chart of the result of having analyzed the decent trimer hydride obtained by comparative example 1 with the gas chromatograph is shown.

Claims (2)

(A) It consists of a decene oligomer hydride having a kinematic viscosity at 40 ° C. of 16 mm ² / s or less, (B) a flash point of 225 ° C. or more, and (C) a pour point of −50 ° C. or less . A base oil for lubricating oil in which 90% by mass or more is decent trimer hydride . As the base oil, the lubricating oil composition characterized by using a lubricating oil base oil of claim 1.

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