JP5237550B2 - Grease - Google Patents

Description

  The present invention relates to grease. More specifically, the present invention relates to a grease containing a base oil mainly composed of an α-olefin oligomer or a hydrogenated product thereof having a very low evaporation amount and a high flash point even if the viscosity is low.

In general, when the viscosity of the base oil is too high, grease may cause deterioration in low-temperature startability and decrease in power efficiency. On the other hand, if it is too low, the evaporation amount may increase or the bearing may be damaged due to insufficient lubricity.
Synthetic lubricating oils used as grease base oils have advantages and disadvantages depending on the purpose of use, but are often low in viscosity and use poly α-olefins from the viewpoint of thermal stability or oxidation stability. However, conventional poly α-olefins contain a large number of isomers even in saturated aliphatic hydrocarbon compounds having the same molecular weight, and specific components (isomers) cannot be removed by a purification method such as distillation. Therefore, even in a synthetic oil having a predetermined viscosity, a mixture of easily volatile components and hardly volatile components is obtained. When such a saturated aliphatic hydrocarbon compound is used as a base oil for grease, the volatile components are volatilized first. During the operation of the machine, the viscosity of the base oil increases, the amount of grease evaporation increases, and at the same time, the low-temperature fluidity deteriorates.

By the way, grease is widely used for lubricating various lubricated portions such as bearings for automobiles and various industrial machines. In recent years, lubrication parts for automobiles and various industrial machines have been designed to operate under a wider range of temperatures and severer lubrication conditions than before.
Therefore, the grease used for them is required to have better low-temperature performance and excellent high-temperature performance. Therefore, it has been required to use a base oil having a low viscosity and a lower evaporation property, that is, a lower evaporation loss.

In addition, small bearings used for electric devices such as CDs, DVDs, HDDs, polygon scanners, etc., have been increasing in speed year by year, and at present, high-speed rotation of 10,000 rpm or more is required.
Once these greases are sealed in the bearing mechanism, lubrication must be maintained for a lifetime without replenishment. Therefore, evaporation loss and decomposition loss of grease base oil must be avoided as much as possible.
With hydrocarbon base oils typified by ordinary mineral oil, evaporation loss increases when the viscosity is reduced (low molecular weight), and it is difficult to achieve both low viscosity and low evaporation.

Under such circumstances, greases based on poly-α-olefins having a lower evaporation property than mineral oil and excellent heat resistance have been used.
As this poly-α-olefin, a product obtained by oligomerizing an α-olefin by cation polymerization using a BF ₃ catalyst and further hydrogenating it is widely used. However, in this production method, the molecular weight distribution of the oligomer cannot be controlled, and a large number of isomers are formed even in compounds having the same degree of polymerization. Therefore, the product obtained by oligomerizing the α-olefin with the BF ₃ catalyst has drawbacks such as being difficult to purify and having a wide boiling range, resulting in a large loss on evaporation (loss).
For example, a hydrogenated decene trimer obtained using a BF ₃ catalyst is disclosed (for example, see Patent Document 1). However, this compound has a low flash point for its high viscosity.
On the other hand, using a metallocene catalyst, a decene oligomer having a number average molecular weight of 500 to 200,000 is produced and subsequently hydrogenated as necessary, and as a lubricant component such as engine oil and gear oil, particularly a viscosity index improver and a thickener. The technique used as is disclosed (for example, see Patent Document 2). However, regarding the grease, there is no disclosure of the oligomer to be specifically used or the content of the grease.

Japanese National Patent Publication No. 10-504326 Special Table 2002-518582

  Under such circumstances, the present invention includes a base oil that has a very low evaporation amount and a high flash point even with low viscosity, and has low temperature performance and low evaporation amount, and also excellent high temperature performance. The purpose is to provide grease.

  As a result of intensive studies to develop a grease having the above-mentioned preferable properties, the present inventors have, as a base oil, an α-olefin oligomer or a hydrogenated product as a main component, and have kinematic viscosity and flash point. It has been found that the purpose can be achieved by using a material having a specific relationship. In addition, the present inventors have found that the object can be achieved by using a base oil containing an α-olefin oligomer obtained by a specific production method or a hydrogenated product thereof. The present invention has been completed based on such findings.

That is, the present invention
(1) α-olefin oligomer and / or α-olefin oligomer hydrogenated product is contained in an amount of 50% by mass or more, and kinematic viscosity and flash point are represented by formula (I)
Flash point (° C.) ≧ 49 × lnγ + 90 (I)
[Where γ is the kinematic viscosity (mm ² / s) at 40 ° C. ]
And (2) (A) a metallocene catalyst, and an α-olefin having 2 to 20 carbon atoms as an oligomer, containing a base oil satisfying the above relationship and a thickener An α-olefin oligomer having 16 to 60 carbon atoms obtained by
(B) (H) α-olefin oligomer hydrogenated product,
A grease (grease II) containing a base oil containing at least one selected from the group consisting of a thickener and a thickener;
Is to provide.

In the present invention, the (3) α-olefin oligomer is an α-olefin oligomer having 16 to 60 carbon atoms obtained by oligomerizing an α-olefin having 2 to 20 carbon atoms using (A) a metallocene catalyst. The grease according to (1), wherein the α-olefin oligomer hydrogenated product is (B) the hydrogenated product of the (A) α-olefin oligomer,
(4) The grease according to (2) above, wherein the base oil contains 50 to 100% by mass of at least one selected from the components (A) and (B).
(5) The grease according to any one of (1) to (4) above, wherein the base oil has a kinematic viscosity at 40 ° C. of 8 to 250 mm ² / s,
(6) The grease according to any one of (1) to (5) above, wherein the thickener is a lithium thickener or a urea thickener,
(7) The above (1) containing at least one selected from a thickener, a lubricity improver, an oily agent, an antioxidant, a rust inhibitor, a metal deactivator, a detergent-dispersant and an antifoaming agent. To the grease according to any one of items (6) to (6)
(8) The grease according to any one of the above (1) to (7), wherein the penetration is 175 to 340, and (9) the above (1) to (8) used for a rolling bearing or a linear bearing. ) Grease according to any one of
It is.

  According to the present invention, even when the viscosity is low, the amount of evaporation is extremely small, and the base oil mainly includes an α-olefin oligomer having a high flash point and a hydrogenated product thereof. It is possible to provide a grease that is small and excellent in high temperature performance.

  The present invention includes an α-olefin oligomer or a hydrogenated product thereof as a main component, a grease containing a base oil having a specific relationship between kinematic viscosity and flash point, and a thickener (Grease I), and A grease (grease II) containing a base oil containing a specific α-olefin oligomer and / or an α-olefin oligomer hydrogenated product and a thickener as a base oil.

In the grease I of the present invention, as the base oil, α-olefin oligomer and / or α-olefin oligomer hydrogenated product is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably. Those containing 90% by mass or more, particularly preferably 100% by mass are used.
The base oil has a kinematic viscosity and a flash point of formula (I)

Flash point (° C.) ≧ 49 × lnγ + 90 (I)
[Where γ is the kinematic viscosity (mm ² / s) at 40 ° C. ]
It is necessary to satisfy this relationship. When the flash point is lower than the value of “49 × lnγ + 90” (γ is the same as described above), the base oil has a large amount of evaporation and a low flash point at the required kinematic viscosity. I can't reach it.

The base oil preferably has a kinematic viscosity and a flash point of the formula (Ia)
Flash point (° C.) ≧ 49 × lnγ + 95 (I−a)
More preferably, the formula (Ib)
Flash point (° C.) ≧ 49 × lnγ + 100 (I−b)
It is desirable to satisfy this relationship.

In the base oil, the kinematic viscosity at 40 ° C. is preferably in the range of 8 to 250 mm ² / s. If this kinematic viscosity is in the above range, it has low viscosity and low evaporation.For example, when oil is supplied to the bearing, the rotational torque during high-speed rotation is low and the amount of evaporation is small even when used in a high-temperature atmosphere. Insufficient lubrication. A more preferable kinematic viscosity at 40 ° C. is 10 to 100 mm ² / s, and further preferably 10 to 70 mm ² / s. The flash point is preferably 200 ° C. or higher, more preferably 210 ° C. or higher, and further preferably 220 ° C. or higher. If the flash point is 200 ° C. or higher, the amount that evaporates and decreases during use of the base oil is reduced, and the life is extended.
The kinematic viscosity is a value measured according to JIS K2283, and the flash point is a value measured by the COC method according to JIS K2265.

The α-olefin oligomer and α-olefin oligomer hydrogenated product used in the base oil of the grease of the present invention include the following (A) α-olefin oligomer and (B) hydrogenated α-olefin oligomer. Is preferred.
By using these (A) α-olefin oligomer and hydrogenated product of (B) α-olefin oligomer, a base oil having a low flashing amount and a high flash point can be obtained even at a low viscosity. It is possible to easily obtain a grease having excellent performance and low evaporation amount and excellent high temperature performance.
[(A) α-olefin oligomer]
The α-olefin oligomer of component (A) preferably used in the base oil is an α-olefin oligomer having 16 to 60 carbon atoms obtained by oligomerizing a C 2 to α 20 olefin using a metallocene catalyst. It is. If the carbon number of the α-olefin oligomer is in the range of 16 to 60, a base oil having a low temperature fluidity, low evaporation property and good oxidation stability can be obtained, and a grease using the base oil has the object of the present invention. Reachable. The preferable carbon number of the α-olefin oligomer is in the range of 20-50.

Examples of the α-olefin having 2 to 20 carbon atoms of the raw material include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and 1-undecene. 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-icosene. Among these, an α-olefin having 8 to 16 carbon atoms is preferable. These α-olefins may be linear or branched. In the present invention, one type may be used alone, or two or more types may be used in combination.
In the present invention, as the metallocene catalyst used for oligomerization of α-olefin, a conventionally known catalyst, for example, (a) a metallocene complex containing a group 4 element of the periodic table, and (b) (b-1) (A) A combination of a compound capable of forming an ionic complex by reacting with the component metallocene complex or a derivative thereof and / or (b-2) an aluminoxane and (c) an organoaluminum compound used as desired. be able to.

As the metallocene complex containing the Group 4 element of the Periodic Table of the component (a), a complex having a conjugated carbon 5-membered ring containing titanium, zirconium or hafnium, preferably zirconium can be used. Here, as a complex having a conjugated carbon 5-membered ring, a complex having a substituted or unsubstituted cyclopentadienyl ligand can be generally mentioned.
Examples of the metallocene complex of the catalyst component (a) include conventionally known compounds such as 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, ethylidenebis (indenyl) zirconium dichloride, biscyclopentadienyl zirconium dichloride, ethylidene Bis (tetrahydroindenyl) zirconium dichloride and bis [3,3- (2-methyl-benzindenyl)] dimethylsilanediylzirconium dichloride, ( , 2'-dimethylsilylene) (2,1'-dimethylsilylene) bis (3-trimethylsilyl-methylindenyl) such as zirconium dichloride.
These metallocene complexes may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the compound (b-1) that can react with the metallocene complex or its derivative to form an ionic complex include dimethylanilinium tetrakispentafluorophenylborate and triphenylcarbenium tetrakispentafluorophenyl. Examples thereof include borates such as borates. These may be used individually by 1 type and may be used in combination of 2 or more type.
Examples of the aluminoxane as the (b-2) compound include chain aluminoxanes such as methylaluminoxane, ethylaluminoxane, butylaluminoxane, and isobutylaluminoxane, and cyclic aluminoxanes. These aluminoxanes may be used alone or in combination of two or more.
In the present invention, as the catalyst component (b), one or more compounds (b-1) may be used, one or more compounds (b-2) may be used, and (b-1) One or more compounds and (b-2) one or more compounds may be used in combination.

The use ratio of (a) catalyst component and (b) catalyst component is preferably 10: 1 to 1: 100 in terms of molar ratio when (b-1) compound is used as (b) catalyst component. Preferably, the range of 2: 1 to 1:10 is desirable, and if it deviates from the above range, the catalyst cost per unit mass polymer increases, which is not practical. When the (b-2) compound is used, the molar ratio is preferably 1: 1 to 1: 1000000, more preferably 1:10 to 1: 10000. When deviating from this range, the catalyst cost per unit mass polymer becomes high, which is not practical.
Examples of the (c) organoaluminum compound used as a catalyst component include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethyl. Examples include aluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride, ethylaluminum sesquichloride, and the like.
These organoaluminum compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

The use ratio of the catalyst component (a) to the catalyst component (c) is preferably 1: 1 to 1: 10000, more preferably 1: 5 to 1: 2000, still more preferably 1:10 to 1 in terms of molar ratio. : The range of 1000 is desirable. By using the catalyst component (c), the polymerization activity per transition metal can be improved. However, if it is too much, the organoaluminum compound is wasted and a large amount remains in the polymer, which is not preferable.
When a catalyst is prepared using the catalyst component (a) and the catalyst component (b), the contact operation is preferably performed in an inert gas atmosphere such as nitrogen gas.
Moreover, when preparing a catalyst using (a) catalyst component, (b) catalyst component, and (c) organoaluminum compound, (b) catalyst component and (c) organoaluminum compound may be contacted in advance. A sufficiently high active catalyst can also be obtained by contacting the component (a), the component (b) and the component (c) in the presence of an α-olefin.
As the catalyst component, one prepared in advance in a catalyst preparation tank may be used, or one prepared in an oligomerization step may be used for the reaction.
The oligomerization of the α-olefin may be either a batch type or a continuous type. 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. Moreover, the use ratio of the catalyst with respect to the α-olefin is such that the molar ratio of the α-olefin / (A) component metallocene complex is usually 1000 to 10 ⁶ , preferably 2000 to 10 ⁵ , and the reaction time is usually 10 minutes to It is about 48 hours.

As a post-treatment of the oligomer reaction, first, a known deactivation treatment is performed by adding water or alcohol to the reaction system, and after the oligomerization reaction is stopped, the catalyst is deashed using an alkaline aqueous solution or an alcohol-alkaline solution. Do. Next, neutralization washing, distillation operation, etc. are performed to remove unreacted α-olefin and olefin isomers by-produced in the oligomerization reaction by stripping, and further isolate α-olefin oligomer having a desired degree of polymerization. To do.
Thus, although the alpha olefin oligomer manufactured by the metallocene catalyst has a double bond, the content of the terminal vinylidene bond is particularly high.
This α-olefin oligomer usually has the general formula (II)

It has the structure which has vinylidene bond at the terminal represented by.
In the general formula (II), p, q and r each independently represent an integer of 0 to 18, n represents an integer of 0 to 8, and when n is 2 or more, q is the same or different for each repeating unit. The value of p + n × (2 + q) + r is 12 to 56.

[(B) α-olefin oligomer hydrogenated product]
The hydrogenated product of the α-olefin oligomer of the component (B) preferably used for the base oil is the hydrogenated product of the α-olefin oligomer of the component (A), which is isolated as described above. The α-olefin oligomer having a degree of polymerization of may be produced by hydrogenation by a known method, or after the above-mentioned oligomerization reaction, after decalcification treatment, neutralization treatment, and washing treatment, You may manufacture by performing hydrogenation, without performing isolation operation of the alpha-olefin oligomer by distillation, and isolating the hydrogenated substance of alpha-olefin oligomer of the desired polymerization degree by distillation after that.

The hydrogenation reaction of α-olefin oligomer is carried out by using known hydrogenation catalysts such as Ni and Co catalysts, noble metal catalysts such as Pd and Pt, specifically diatomaceous earth-supported Ni catalysts, cobalt trisacetylacetonate / organoaluminum. The reaction is performed using a catalyst such as a catalyst, a palladium catalyst supported on activated carbon, or a platinum catalyst supported on alumina.
The conditions for the hydrogenation reaction are typically 150 to 200 ° C. for Ni-based catalysts and 50 to 150 ° C. for homogeneous noble metal catalysts such as Pd and Pt, and homogeneous systems such as cobalt trisacetylacetonate / organoaluminum. If it is a catalyst, it will normally be set as the temperature range of 20-100 degreeC, and a hydrogen pressure is a normal pressure-about 20 Mpa.
If the reaction temperature in each catalyst is in the above range, it is possible to suppress the formation of isomers in oligomers having an appropriate reaction rate and having the same degree of polymerization.
This hydrogenated product of α-olefin oligomer is usually represented by the general formula (III)

It has the structure represented by these.
In the general formula (III), a, b, c and m are the same as p, q, r and n in the general formula (II), respectively.
The hydrogenated product of the α-olefin oligomer is more preferable from the viewpoint of oxidation stability and the like than the α-olefin oligomer having a vinylidene bond at the terminal of the component (A).

In the base oil preferably used for the grease of the present invention, in addition to the α-olefin oligomer and the hydrogenated product thereof as component (A) and component (B), other base oils are contained in an amount of 50% by mass or less, preferably It can be contained in a proportion of 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less.
As other base oils, mineral oil base oils and / or synthetic oil base oils usually used for grease can be used.
Mineral oil base oils include, for example, solvent oil removal, solvent extraction, hydrocracking, solvent dewaxing, hydrogen removal of lubricating oil fractions obtained by distillation under reduced pressure of atmospheric residue obtained by atmospheric distillation of crude oil. Base oils produced by isomerizing waxes produced by one or more treatments such as hydrorefining, mineral oil wax, or Fischer-Tropsch process, etc. It is done.

These mineral oil base oils preferably have a viscosity index of 90 or more, more preferably 100 or more, and even more preferably 110 or more. If the viscosity index is 90 or more, there is an effect that the viscosity index of the composition is kept high and the object of the present invention is easily achieved.
Further, the aromatic content (% C _A ) of the mineral oil base oil is preferably 3 or less, preferably 2 or less, more preferably 1 or less, and the sulfur content is preferably 100 mass ppm or less, More preferably, it is 50 mass ppm or less. % C _A is less than or equal to 3, if the sulfur content of less than 100 mass ppm, it is possible to maintain good oxidative stability of the composition.

On the other hand, as synthetic oil base oils, α-olefin oligomers obtained by conventional methods (BF ₃ catalyst, Ziegler type catalyst, etc.) and hydrogenated products thereof, di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate, etc. Examples include diesters, trimethylolpropane caprylate, polyol esters such as pentaerythritol-2-ethylhexanoate, aromatic synthetic oils such as alkylbenzene and alkylnaphthalene, polyalkylene glycols, and mixtures thereof. Of these, α-olefin oligomers obtained by conventional methods (BF ₃ catalyst, Ziegler catalyst, etc.) and hydrogenated products thereof are suitable.
In the present invention, as the other base oil, a mineral oil base oil, a synthetic oil base oil, or an arbitrary mixture of two or more selected from these can be used. Examples thereof include one or more mineral oil base oils, one or more synthetic oil base oils, a mixed oil of one or more mineral oil base oils and one or more synthetic oil base oils, and the like.

On the other hand, in the grease II of the present invention, as a base oil,
(A) an α-olefin oligomer having 16 to 60 carbon atoms obtained by oligomerizing a C 2 to 20 α-olefin using a metallocene catalyst,
(B) (H) α-olefin oligomer hydrogenated product,
A base oil containing at least one selected from the above is used.
In the grease I, the α-olefin oligomer and the hydrogenated product of the α-olefin oligomer of the components (A) and (B) are [(A) α-olefin oligomer] and [( B) α-olefin oligomer hydrogenated product] can be used.

In the grease II of the present invention, as a base oil, at least one selected from the above-mentioned components (A) and (B) α-olefin oligomers and hydrogenated products of α-olefin oligomers is used in an amount of 50 to 100 masses. %, Preferably 70 to 100% by mass, more preferably 80 to 100% by mass, particularly preferably 90 to 100% by mass.
If the base oil contains 50 mass% or more of the α-olefin oligomer of the components (A) and (B) or a hydrogenated product thereof, the amount of evaporation is small and the flash point is low even if the viscosity is low. A high base oil can be obtained, and a grease having excellent low temperature performance, low evaporation, and excellent high temperature performance can be easily obtained.
In addition to the α-olefin oligomer of the component (A) and component (B) and hydrogenated products thereof, the base oil contains 50% by mass or less, preferably 70% by mass or less, and more preferably other base oils. Can be contained in a proportion of 80% by mass or less, particularly preferably 90% by mass or less. As the other base oil, the same base oil as exemplified in the description of the grease I can be used.
The preferable kinematic viscosity at 40 ° C. and flash point of the base oil of Grease II are the same as in Grease I.

The grease 1 and grease II of the present invention can be obtained by blending a thickener together with the above base oils.
There is no restriction | limiting in particular as a thickener used for this invention, Both soap type and a non-soap type can be used. As this thickener, those having a dropping point of grease of 230 ° C. or higher are preferable. When the dropping point is 230 ° C. or higher, it is possible to suppress lubrication problems such as softening at high temperature, leakage associated therewith, and seizure.

Examples of soaps include metal soaps obtained by saponifying carboxylic acids or their esters with metal hydroxides such as alkali metals or alkaline earth metals.
Examples of metals include sodium, calcium, lithium, and aluminum. Examples of carboxylic acids include crude fatty acids obtained by hydrolyzing fats and oils to remove glycerin, monocarboxylic acids such as stearic acid, and 12-hydroxystearic acid. Examples thereof include dibasic acids such as monohydroxycarboxylic acid and azelaic acid, and aromatic carboxylic acids such as terephthalic acid, salicylic acid and benzoic acid. These may be used individually by 1 type and may be used in combination of 2 or more type.
Specifically, lithium-based lithium soap using 12-hydroxystearic acid is suitable. In blending the soap-based thickener, the carboxylic acid and the metal hydroxide may be added to the base oil and saponified in the base oil.

Other complex soaps include other soap-based thickeners. As this complex soap, lithium complex soap, aluminum complex soap, calcium complex soap, calcium sulfonate complex soap and the like are used.
Among these, lithium-based lithium complex soaps include fatty acids such as stearic acid, oleic acid, and palmitic acid and / or hydroxy fatty acids having 12 to 24 carbon atoms having one or more hydroxyl groups in the molecule, and aromatic carboxylic acids. And / or obtained by reacting an aliphatic dicarboxylic acid having 2 to 12 carbon atoms (more preferably 4 to 9 carbon atoms) with a lithium compound such as lithium hydroxide. Since it is excellent in property, it is more preferable as a thickener.
The hydroxy fatty acid having 12 to 24 carbon atoms is not particularly limited, and examples thereof include 12-hydroxystearic acid, 12-hydroxylauric acid, and 16-hydroxypalmitic acid. Among these, 12-hydroxystearic acid is particularly preferable. Acid is preferred.

Examples of the aromatic carboxylic acid include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, salicylic acid, p-hydroxybenzoic acid and the like.
The aliphatic dicarboxylic acid having 2 to 12 carbon atoms is not particularly limited, and examples thereof include azelaic acid, sebacic acid, oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, suberic acid, undecanedioic acid, Examples include dodecanedioic acid, and among these, azelaic acid is preferable.
Here, in the total mass of fatty acid and / or hydroxy fatty acid having 12 to 24 carbon atoms having one or more hydroxyl groups in the molecule and aromatic carboxylic acid and / or aliphatic dicarboxylic acid having 2 to 12 carbon atoms The aromatic carboxylic acid and / or the aliphatic dicarboxylic acid having 2 to 12 carbon atoms is preferably 20 to 90% by mass. If it is in the range of 20 to 90% by mass, a thermally stable thickener can be obtained, which is advantageous for realizing a long life of the grease at a high temperature.
Among these soap-based thickeners, lithium-based thickeners are preferable, and lithium complex soap is particularly preferable.

Examples of non-soap systems include urea compounds and organically treated bentonite.
Here, as a urea compound as a thickener, any can be used from the urea compounds conventionally used as a urea-based thickener. Examples of the urea compound include a diurea compound, a triurea compound, a tetraurea compound, and a urea / urethane compound.
A urea compound is excellent in both heat resistance and water resistance, and particularly excellent in stability at high temperatures, and therefore is suitably used in a high temperature location.

As the diurea compound, a compound represented by R ¹ NHCONHR ² NHCONHR ³ (R ¹ and R ³ are each independently a monovalent chain hydrocarbon group having 6 to 24 carbon atoms, monovalent having 6 to 12 carbon atoms, Alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ⁵ represents a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms). Typical examples include those obtained by reacting a diisocyanate and a monoamine. Examples of the diisocyanate include diphenylmethane diisocyanate and tolylene diisocyanate. Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, cyclohexylamine, and aniline. , Toluidine, octadecylamine, oleylamine and the like.

In the present invention, among the above-mentioned various thickeners, lithium-based thickeners, preferably lithium complex soaps and urea-based thickeners are preferably used.
The blending amount of the above-mentioned various thickeners in the grease is not particularly limited as long as the grease properties can be obtained, and is preferably 10 to 30% by mass, more preferably 10 to 20% by mass based on the grease. %.
The thickener used in the grease according to the present invention is for imparting consistency. If the blending amount is too small, the desired consistency cannot be obtained. On the other hand, if the blending amount is too large, the lubricity of the grease decreases. .

The grease of the present invention has various known additives such as thickeners, lubricity improvers, detergent dispersants, antioxidants, corrosion inhibitors, rust inhibitors, A foaming agent etc. can be added suitably.
Examples of the thickener include polybutene, polyisobutylene, polymethacrylate (PMA), olefin copolymer (OCP), polyalkylstyrene (PAS), styrene-diene copolymer (SCP), and the like.
Examples of the lubricity improver include sulfur compounds (sulfurized oils and fats, sulfurized olefins, polysulfides, sulfide mineral oils, thiophosphoric acids, thiocarbamic acids, thioterpenes, dialkylthiodipyropionates, etc.), phosphate esters, phosphites , (Tricresyl phosphate, triphenyl phosphite, etc.), etc., higher fatty acids such as oleic acid and stearic acid, and oily agents such as higher aliphatic alcohols such as oleyl alcohol and stearyl alcohol, etc. Examples include succinimide and boron succinimide.

  As the antioxidant, amine-based antioxidants, phenol-based antioxidants and sulfur-based antioxidants can be used, and among them, amine-based antioxidants are preferable. Examples of the amine antioxidant include monoalkyl diphenylamine compounds such as monooctyl diphenylamine and monononyl diphenylamine, 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine, 4 , 4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine, 4,4′-dinonyldiphenylamine, and other dialkyldiphenylamine compounds, tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, and polynonyldiphenylamine Alkyldiphenylamine compounds, α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, pentylpheny -α- naphthylamine, hexylphenyl -α- naphthylamine, heptylphenyl -α- naphthylamine, octylphenyl -α- naphthylamine, and naphthylamine-based compounds such as nonylphenyl -α- naphthylamine.

Examples of the corrosion inhibitor include benzotriazole and thiazole, examples of the rust preventive include metal sulfonate and succinate, and examples of the antifoaming agent include silicone and fluorinated silicone. Can be mentioned.
The blending amount of these additives may be appropriately selected according to the purpose, but is usually blended so that the total of these additives is 30% by mass or less based on the lubricant.
Examples thereof include aliphatic saturated and unsaturated monocarboxylic acid amides such as acid amides and oleic acid amides.
These may be used individually by 1 type and may be used in combination of 2 or more type. Further, the blending amount is usually selected in the range of 0.01 to 20% by mass, preferably 0.1 to 10% by mass, based on the total amount of the lubricating oil composition.

There is no restriction | limiting in particular about the preparation method of the grease based on this invention, Usually, the following method can be used.
First, a predetermined proportion of thickener and, if desired, a thickener are blended into a part of the base oil, and heated to a predetermined temperature for homogenization. Thereafter, the remaining base oil is blended and cooled, and when a predetermined temperature is reached, a predetermined amount of various additives are blended as desired, whereby the grease according to the present invention can be obtained.

The grease of the present invention is a grease containing a base oil mainly composed of an α-olefin oligomer having a high flash point and a high flash point even when the viscosity is low, and having excellent low-temperature performance. It is a grease with low evaporation and excellent high-temperature performance. The grease of the present invention has a consistency (mixing consistency) of usually 175 to 340, a relatively low mixing consistency of 265 to 295, and a consistency grade by NLGI (National Lubricating Grease Institute). No. It is easy to obtain a grease that is 2.
Therefore, the grease of the present invention can be effectively used as a grease used for a lubricated portion having a large mechanical load such as stirring.
The penetration degree is a value determined based on JIS K 2560.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various characteristics were determined according to the following methods.
(1) Kinematic viscosity at 40 ° C. of base oil Measured according to JIS K2283.
(2) Grease consistency and blending consistency Measured according to JIS K2220.7 (3) Grease dropping point Measured according to JIS K2220.8.
(4) Low temperature torque test It measured based on JISK2220.18.
(5) High temperature bearing life test The temperature was measured at 180 ° C. according to ASTM D3336.
(6) Evaporation test It measured based on JISK2220 * 10.

Production Example 1: Production of 1-decene oligomer (trimer) hydrogenated product (a) Oligomerization of decene Decene monomer (Idemitsu Kosan Co., Ltd.) in a three-necked flask having an internal volume of 5 liters under an inert gas stream Manufactured by: Linearene 10) 4 liters (21.4 mol) was charged, and methylalumoxane dissolved in toluene (converted to Al: same as biscyclopentadienylzirconium dichloride dissolved in toluene (complex mass 1168 mg: 4 mmol)) 40 mmol) was added. 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.
(B) Hydrogenation of decene oligomer Cobalt trisacetylacetonate (catalyst weight: 3.0 g) in which 3 liters of decene oligomer produced in (a) 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 (a hydrogenated product of 1-decene trimer).

Production Example 2: Production of 1-decene oligomer (tetramer) hydrogenated product A fraction at a top temperature of 261 ° C. and a bottom temperature of 293 ° C. at 0.5 Torr from the residue of Production Example 1 by distillation under reduced pressure (4 of 1-decene) The hydrogenated product) was separated.

Reference Example 1, Example 1 and Comparative Examples 1-3
A lithium complex grease having the composition shown in Table 1 was prepared, and a dropping point, a low temperature torque test and an evaporation amount were measured. The results are shown in Table 1.
The grease was manufactured by the following method.
(I) The reaction kettle is charged with 1/2 (mass) of the base oil to be used and 11.5% by mass of 12-hydroxystearic acid and 1.0% by mass of the rust inhibitor with respect to the total amount of grease. And dissolved by heating with stirring.
(Ii) An aqueous solution in which an amount corresponding to 3.1% by mass of lithium hydroxide (monohydrate) and 2.4% by mass of terephthalic acid is dissolved in water with respect to the total amount of grease is added to the above (i). Heat mixed. After the grease temperature reached 205 ° C., it was held for 5 minutes.
(Iii) Next, after the remaining base oil was added, it was cooled to 80 ° C. at 50 ° C./1 hour, and the amine antioxidants shown in Table 1 were added and mixed.
(Iv) Further, after naturally cooling to room temperature, a finishing treatment was performed using a three-roll apparatus to obtain a grease.

[note]
1) Trimer of 1-decene trimer synthesized by the metallocene catalyst obtained in Production Example 1 2) Tetramer of 1-decene tetramer synthesized by the metallocene catalyst obtained in Production Example 2 Additive 3) Polyalphaolefin (1-Chemicals, trade name “DURASYN-164”) which is an oligomer of 1-decene by a conventional method
4) Polyalphaolefin (an oligomer of BP Chemicals, trade name “DURASYN-166”) which is an oligomer of 1-decene by a conventional method
5) Polyalphaolefin (an oligomer of BP Chemicals, trade name “DURASYN-168”) which is an oligomer of 1-decene by a conventional method
6) Lithium complex grease obtained by reacting 12-hydroxystearic acid and terephthalic acid with lithium hydroxide 7) Dioctyldiphenylamine 8) Ca sulfonate

As can be seen from Table 1 , the lithium complex grease of Reference Example 1 that satisfies the requirements of Grease I and Grease II has less evaporation than the grease of Comparative Example 1, although the 40 ° C. kinematic viscosity of the base oil is lower. The low temperature torque is small. In addition, the grease of Example 1 has substantially the same low-temperature torque and less evaporation than the grease of Comparative Example 2, although the 40 ° C. kinematic viscosity of the base oil is higher. Further, the grease of Example 2 has a lower evaporation amount and a lower low temperature torque than the grease of Comparative Example 3, although the base oil has a considerably lower kinematic viscosity at 40 ° C.

Reference Example 2 and Comparative Example 4
Urea greases having the compositions shown in Table 2 were prepared and subjected to a dropping point, a low temperature torque test and a bearing life test. The results are shown in Table 2.
The grease was manufactured by the following method.
(I) An amount corresponding to 6.4% by mass of diphenylmethane-4,4′-diisocyanate based on the total amount of grease is added to 2/3 (mass) of the base oil to be used, dissolved by heating, and the raw material 1 It was.
(Ii) In addition, octylamine was added to the remaining 1/3 base oil in an amount corresponding to 6.6% by mass with respect to the total amount of grease, and the mixture was dissolved by heating to obtain raw material 2.
(Iii) Next, the raw material 2 was gradually introduced into the grease reaction kettle while vigorously stirring the raw material 1 at 50 to 60 ° C. The mixture was further heated with stirring, and kept for 1 hour after the temperature of the grease reached 165 ° C.
(Iv) Thereafter, aralkylated naphthylamine was added and mixed, and the mixture was allowed to cool naturally to room temperature, followed by finishing using a three-roll apparatus to obtain a grease.

[note]
9) a reaction product of diphenylmethane-4,4′-diisocyanate and 2 moles of octylamine,
1), 3), 7) and 8) are the same as Table 1.

From Table 2 , the urea grease of Reference Example 2 that satisfies the requirements of Grease I and Grease II has less evaporation than the grease of Comparative Example 4 although the base oil has a lower kinematic viscosity at 40 ° C. and has a bearing life. Is long and low temperature torque is small.

  The grease of the present invention has excellent low-temperature performance, low evaporation, and high-temperature performance.For example, various bearings such as automobile bearings, motor bearings, generator bearings, and small bearings for electronic equipment, It is suitable for use as grease for machine tools, industrial robots, linear motion devices such as injection molding.

Claims (4)

It contains 50 to 100% by mass of a hydrogenated product of an α-olefin oligomer having 40 carbon atoms obtained by oligomerization of 1-decene using a metallocene catalyst, and has a kinematic viscosity at 40 ° C. of 10 to 70 mm ² / s. And the kinematic viscosity and flash point are of formula (I)
Flash point (° C.) ≧ 49 × lnγ + 90 (I)
[Where γ is the kinematic viscosity (mm ² / s) at 40 ° C. ]
A grease characterized by containing a base oil satisfying the above relationship and a thickener made of lithium complex soap . The grease according to claim 1, comprising at least one selected from a thickener, a lubricity improver, an antioxidant, a rust inhibitor, a metal deactivator, a detergent dispersant, and an antifoaming agent. The grease according to claim 1 or 2, which has a penetration degree of 175 to 340. The grease according to any one of claims 1 to 3 , which is used for a rolling bearing or a linear motion bearing.