JP2503536B2 - Lubricating oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a lubricating oil having a high viscosity index, a low temperature viscosity, a large thickening property, and excellent shear stability, heat resistance, and oxidation resistance. It relates to a composition.

[Conventional technology]

As a lubricating oil composition with a high viscosity index and excellent shear stability and oxidation resistance, it has a kinematic viscosity of 40 to 1 at 100 ° C.
000 cSt poly-alpha-olefins, synthetic hydrocarbons with kinematic viscosities of 1-10 cSt at 100 ° C, esters with kinematic viscosities of 1-10 cSt at 100 ° C, and essentially dispersants, antioxidants, corrosion inhibitors, resistant A lubricant composition has been proposed which comprises an additive package containing at least one additive selected from the group consisting of abradability, pour point depressant, rust preventive, foam suppressor and extreme pressure agent (Japanese Patent Laid-Open No. 2000-242242). (Sho 59-89397).

This lubricant composition uses the above as a base oil,
This is a mixture of a thickener and an additive.
Examples of the thickener include 1-octene, 1-decene, 1-
Relatively long chain α-olefin oligomers such as dodecene have been used.

[Problems to be solved by the invention]

However, since such a conventional lubricating oil composition does not have a high viscosity index and the temperature dependence of the viscosity is large, designing to maintain the high temperature viscosity at a certain value increases the low temperature viscosity and increases the viscosity. There was a problem that the viscosity was also small.

In order to solve the above problems, the object of the present invention is to provide a lubricating oil composition having a high viscosity index, a low temperature viscosity and a large thickening property, as well as excellent shear stability, heat resistance and oxidation resistance. It is to be.

[Means for solving problems]

(A) One or more base oils selected from synthetic hydrocarbons and esters having a kinematic viscosity at 100 ° C of 1 to 20 cSt
50 to 99.8 parts by weight, (B) 100 ° C kinematic viscosity of 1000 to 10,000cSt, 135 ° C
Intrinsic viscosity [η] in decalin is 0.5 dl / g or less, number average molecular weight measured by gel permeation chromatography is 2000-7800, Q value measured by gel permeation chromatography (weight average molecular weight / number average) Molecular weight) is 4 or less, and standard deviation σ of ethylene composition
Is a lubricating oil composition containing 0.2 to 50 parts by weight of one or more thickeners selected from ethylene / α-olefin cooligomers of 0 to 3.

The base oil of component (A) used in the present invention is 100 ° C.
A synthetic hydrocarbon or / and ester oil having a kinematic viscosity of 1 to 20 cSt, which is conventionally used, can be used. For example, the kinematic viscosity at 100 ℃ is 1 ~ 20c
Examples of the synthetic hydrocarbon of St include α-olefin oligomers, alkylbenzenes, alkylnaphthalenes and the like, and these are used alone or in combination of two or more kinds.

Among them, as the α-olefin oligomer, a low molecular weight oligomer of α-olefin composed of C ₈ (octene) to C ₁₂ (dodecene) or a mixture of these olefins can be used. The low viscosity α-olefin oligomer can be produced by Ziegler catalyst, thermal polymerization, free radical catalyzed polymerization, or polymerization using BF ₃ as a catalyst. These polymerization methods are described, for example, in U.S. Pat.
It is described in No. 8.

The alkylbenzenes and alkylnaphthalenes are produced by Friedel-Crafts alkylation of benzene or naphthalene with an olefin, and such alkylbenzenes or alkylnaphthalenes are
Usually most are dialkylbenzenes or dialkylnaphthalenes with alkyl chain lengths of 6 to 14 carbon atoms. The alkylated olefins used in the production of alkylbenzenes or alkylnaphthalenes may be linear or branched olefins or combinations thereof. These manufacturing methods are shown, for example, in US Pat. No. 3,909,432.

The low viscosity ester having a kinematic viscosity at 100 ° C. of 1 to 20 cSt includes, for example, a monoester produced from a monobasic acid such as pelargonic acid and an alcohol; a dibasic acid and an alcohol, or a diol and a monobasic acid or Diesters produced with acid mixtures; produced by reacting diols, triols (eg trimethylolpropane), tetraols (eg pentaerythritol), hexaols (eg dipentaerythritol) with monobasic acids or acid mixtures Examples thereof include polyol ester. Examples of these esters are tridecyl pelargonate, di-2-ethylhexyl adipate, di-
2-ethylhexyl azelate, trimethylolpropane triheptanoate, pentaerythritol tetraheptanoate and the like can be mentioned.

The thickener of the component (B) used in the present invention has a viscosity increase of 100 to 10,000 cSt at 100 ° C., preferably 1100 to 6500 cS.
The ethylene / α-olefin cooligomer having an intrinsic viscosity [η] of 0.5 dl / g or less in decalin at 1,500 to 5,000 cSt and 135 ° C. is particularly preferable. Intrinsic viscosity [η]
When it exceeds 0.5 dl / g, only poor shear stability and solubility can be obtained. Such an ethylene / α-olefin cooligomer has an ethylene component unit of 20 to
80 mol%, preferably 30-70 mol%, particularly preferably 40
~ 60 mol%, α- olefin component unit is 20 to 80 mol%,
Preferably 30-70 mol%, particularly preferably 40-60 mol%
And the number average molecular weight (n) measured by gel permeation chromatography (GPC) is 2000.
~ 7800, preferably 2300-5000, particularly preferably 2500-
Transparent liquid low molecular weight ethylene / α-olefin copolymerization weight in the range of 4500 and having a Q value (weight average molecular weight / number average molecular weight) measured by GPC of 4 or less, preferably 3.5 or less, particularly preferably 3.0 or less. Use coalescence.

When the number average molecular weight (n) is less than 2000, the viscosity index is low, the low temperature viscosity is high, the pour point is high, the viscosity increase is small, the addition amount is large, and the weight loss due to volatilization is large. . On the other hand, when it exceeds 7800, the shear stability and the solubility become poor. When the Q value is within the above range, the shear stability is particularly good, the weight loss due to volatilization of the composition is small, and the heat resistance and the oxidation resistance are excellent. Stability,
The heat resistance and oxidation resistance are poor, and the weight loss due to volatilization is large.

The standard deviation value σ of the ethylene composition of this ethylene / α-olefin cooligomer is usually 0 to 3, preferably 0.
2, particularly preferably in the range of 0 to 1. The standard deviation value σ of the ethylene composition of the ethylene / α-olefin cooligomer is calculated as follows.

That is, hexane, which is a good solvent for ethylene / α-olefin oligomer, and acetone, which is a poor solvent, are used as a hexane alone solvent and hexane / acetone (hereinafter, referred to as H / A
Say. ) Is 4/1, 3/2, 1/4 (volume ratio), and the co-oligomer is first dissolved in hexane alone solvent.

Of the fraction 1 that does not dissolve in hexane alone (the highest ethylene composition) and the fraction 2 that dissolves in it, fraction 2 is separated and dissolved in the H / A mixed solvent (4/1), and similarly fraction 3 is not dissolved. Of the fractions 4 that dissolve with, the fractions 4 are separated and dissolved in the H / A mixed solvent (3/2), and similarly, the fractions 5 of the undissolved fractions 5 and the soluble fractions 6 are separated. Dissolve in H / A mixed solvent (1/4) to obtain insoluble fraction 7 and soluble fraction 8.

Then, 5 fractions having different compositions of fractions 1, 3, 5, 7, and 8 were desolvated, and the weights M _{1 to} M ₅ of the cooligomers of each fraction were determined. The weight fraction Wi of each fraction was Mi / M ₁ It is represented by + M ₂ + M ₃ + M ₄ + M ₅ , and IR analysis gives the ethylene composition Ei of each fraction.

The standard deviation value σ is obtained by calculation according to the following equation using the ethylene composition Ei and the weight fraction Wi of each fraction. The larger the standard deviation value σ of the ethylene composition, the wider the composition distribution.

In the above formula, Ei represents the ethylene composition of the fraction, Wi represents the weight fraction of the i fraction, and represents the average ethylene composition of the copolymer. When the standard deviation value σ of the ethylene composition is in the above range, the resulting lubricating oil composition has a transparent and excellent appearance, and also has good thermal stability, oxidation resistance, solubility, and low temperature viscosity. Low and excellent shear stability. When the standard deviation value σ exceeds 3, the ethylene composition E has a high low-temperature viscosity and is poor in heat resistance and oxidation resistance due to a fraction in which the ethylene composition E largely deviates to the negative side. On the other hand, the transparency and the solubility are deteriorated due to a large variation in the positive side.

In the present invention, the kinematic viscosity is measured according to JIS K2283. Further, the ethylene content in the ethylene / α-olefin cooligomer is measured by ¹³ C-NMR analysis. The number average molecular weight was previously calibrated using standard substances of known molecular weight (monodisperse polystyrene and squalane).
Measured by C. The Q value was measured by measuring the GPC count using a standard substance of known molecular weight (monodisperse polystyrene w500 to 840 × 10 ⁴ , 16 pieces), and measuring the molecular weight and EV (Elution V
olume) correlation diagram (calibration curve). And G
The GPC pattern of the sample is taken by the PC method, the molecular weight is obtained from the calibration curve, and then the Q value is calculated.

Examples of the α-olefin component unit that is a constituent of the ethylene / α-olefin cooligomer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 3-methyl-1-pentene. , 1-
Examples of the α-olefin having 3 to 20 carbon atoms include octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-octadecene.
A mixed component of two or more of these α-olefins may be used.

As a method for producing the ethylene / α-olefin cooligomer, in the presence of hydrogen, a catalyst formed from a soluble vanadium compound and an organoaluminum compound is used,
Ethylene and α-olefin are continuously copolymerized in a liquid phase, the vanadium compound concentration in the re-polymerization system is 0.3 mmol or more per liquid phase, and the vanadium compound supplied to the polymerization system is a vanadium compound of the polymerization system. There is a method in which the polymerization medium is diluted and supplied so that the concentration becomes 5 times or less the concentration.

Vanadium compounds include VOCl ₃ , VO (OC ₂ H ₅ ) C
l ₂ , VO (OC ₂ H ₅ ) _1.5 , Cl _1.5 , VCl ₄ and other general formulas VO (O
R) _n X _3-n or VX ₄ (wherein R is an aliphatic hydrocarbon group, X
Is halogen and 0 ≦ n ≦ 3. The compound shown by these can be used. As the organoaluminum compound,
_{(C 2 H 5) 3 Al} , (C 2 H 5) 2 AlCl, (C 2 H 5) 1.5 AlCl 1.5,
_{(Iso-C 4 H 9)} 1.5 AlCl 1.5, (C 2 H 5) 3 AlCl 2, the general formula ^{_{R 1 m AlX 1 3-m}} ( wherein R ₁ of a mixture thereof is an aliphatic hydrocarbon group, X ^The compound represented by ¹ is halogen and 1 ≦ m ≦ 3 can be used.

As the polymerization medium, pentane, hexane, heptane,
Hydrocarbons such as kerosene, cyclohexane and toluene can be used. The vanadium compound concentration in the liquid phase is 0.3 mmol / min or more, preferably 0.5 to 20 mmol /, and the organoaluminum compound concentration is Al / V (atomic ratio) of 2 to 5
It may be set to 0, particularly 3 to 20.

Copolymerization temperature is 0 to 100 ° C, especially 20 to 80 ° C, polymerization pressure is 0 to 50 kg / cm ² (gauge pressure), particularly 0 to 30 kg / cm ² (gauge pressure), average residence time is 5 to 300 minutes, In particular, polymerization conditions such as 10 to 250 minutes may be adopted.

The lubricating oil composition of the present invention comprises 50 to 99.8 parts by weight of the component (A), preferably 60 to 95 parts by weight, and 0.2 to 5 parts of the component (B).
0 parts by weight, preferably 5 to 40 parts by weight,
The mixing ratio of the component (A) and the component (B) is set so that the kinematic viscosity of the composition becomes a predetermined value. When the compounding ratio of the component (A) and the component (B) is within the above range, an economical lubricating oil composition having excellent shear stability, a high viscosity index and a low temperature viscosity can be obtained.

In addition to the above components of the lubricating oil composition of the present invention, other components such as various additives may be blended. Additives that can be blended include detergents such as neutral and basic sulfonates and phenates (metal salt type); dispersants such as succinimide, ester and benzylamine, and copolymeric polymers (ashless type); Condensates of chlorinated paraffins with naphthalene or phenol, pour point depressants such as polyalkyl acrylates and methacrylates, polybutenes, polyalkylstyrenes, polyvinyl acetates; antioxidants such as zinc thiophosphate, trialkylphenols; sulfuric acid, sulfones Emulsifiers such as acids and phosphates, fatty acid derivatives, amine derivatives, quaternary ammonium salts, polyoxyethylene-based activators; Demulsifiers such as quaternary ammonium salts, sulfated oils, phosphates, etc .; Phenolic compounds, formaldehyde Mold prevention of donor compounds, salicylanilide compounds, etc. Agent; Sutin inhibitors; anti-chatter agents, anti-squawk agents; such as extreme pressure additives and the like.

The lubricating oil composition of the present invention can be obtained by mixing the above-mentioned components (A) and (B) and other components to be blended if necessary. The lubricating oil composition of the present invention can be used as it is as a lubricating oil or a lubricating oil base in the same manner as conventional ones, particularly gear oils for automobiles or industries; operation of automobiles, aircraft, robots, molding machines, etc. Oil: Suitable for use as engine oil.

 The lubricating oil composition of the present invention has the following properties.

High viscosity index.

When designing normal lubricating oil (gear oil, engine oil, etc.), the kinematic viscosity at 100 ° C is adjusted to maintain load bearing performance at high temperatures, but when the viscosity index is high, the kinematic viscosity at 40 ° C is low. Will be lower than if.

Low temperature viscosity.

Therefore, the engine oil has good startability in cold regions. In general, energy loss can be reduced in the application of lubricating oil such as gear oil and engine oil.

Greatly thickened.

 Therefore, the amount of thickener used is reduced.

If various thickeners (eg, olefin copolymer type, polymethacrylate type) are used instead of ethylene / α-olefin cooligomer, shear stability is poor, viscosity decreases with time of use, and load resistance decreases. However, this composition has very good shear stability.

Compared with mineral oil base, viscosity index is considerably higher, low temperature viscosity is much lower, heat resistance and oxidation resistance are much better,
Good shear stability.

〔The invention's effect〕

As described above, since the lubricating oil composition of the present invention contains the specific ethylene / α-olefin cooligomer in the base oil, it has a higher viscosity index and a lower low temperature viscosity than conventional ones, and a large viscosity increase. It can reduce the use of sticky agent and has excellent shear stability, heat resistance and oxidation resistance.

〔Example〕

Examples of the present invention will be described below. Table 1 shows the evaluation methods in the examples.

Examples 1 to 3 ethylene / propylene cooligomer (I) (ethylene
60 mol%, n7800, kinematic viscosity at 100 ℃ 4950cSt,
[Η] 0.45 dl / g, Q value 2.0, σ value 0.1 or less), ethylene /
Propylene cooligomer (II) (ethylene 55 mol%,
n4000, kinematic viscosity at 100 ℃ 3100cSt, [η] 0.24dl /
g, Q value 2.2, σ value 0.1 or less), or ethylene / propylene cooligomer (III) (ethylene 53 mol%, n370
Kinematic viscosity at 0 and 100 ℃ 2060cSt, [η] 0.20dl / g, Q
Value 2.4, σ value 0.1 or less), and poly α-olphine oligomer (PAO-6, manufactured by Chegron Chemical Co., Synfluid 6cSt P
AO, trade name, kinematic viscosity at 100 ° C 6cSt, viscosity index 135)
Was mixed in the proportions shown in Table 2 at 100 ° C. for 1 hour to obtain a lubricating oil composition, and its characteristics were evaluated.

Example 4 Instead of PAO-6 in Examples 1 to 3, ester oil DIDA (manufactured by Daihachi Chemical Co., Ltd., trade name, kinematic viscosity at 100 ° C. is 3.5 cS).
t, viscosity index 138) were used in the proportions shown in Table 2 for evaluation.

Comparative Example 1 Ethylene / Propylene Cooligomer (IV) (Ethylene
49 mol%, n1400, kinematic viscosity at 100 ℃ 100cSt,
[Η] 0.07 dl / g, Q value 1.5, σ value 0.1 or less) were evaluated alone for comparison.

Comparative Example 2 Poly α-olefin oligomer (PAO-100, Mobil Ch
manufactured by emical, SHF-1001, trade name, kinematic viscosity at 100 ° C
100 cSt) alone was evaluated for comparison.

Comparative Examples 3 to 4 Ethylene / propylene cooligomer (III) and ethylene / propylene cooligomer (V) (48 mol% ethylene, n1000, kinematic viscosity at 100 ° C. 40 cSt, [η] 0.05d
l / g, Q value 1.4, σ value 0.1 or less) and ethylene / propylene oligomer (VI) (ethylene 46 mol%, n2100, 1)
Kinematic viscosity at 00 ° C 5000cSt, [η] 0.26dl / g, Q value 6.
7, σ value 6.0) were mixed in the proportions shown in Table 2 and evaluated. The composition in which the ethylene / propylene oligomer (VI) was mixed was cloudy.

Comparative Example 5 An ethylene / propylene copolymer (60 mol% ethylene, n65,000, w / n = 1.5, [η] 0.52 dl / g) and PAO-6 were blended in the proportions shown in Table 2 and evaluated.

 The above results are summarized in Table 2.

Example 5, Comparative Examples 6 to 8 In addition to those used in Example 3 and Comparative Example 5, ethylene / propylene cooligomer (VII) (49 mol% ethylene, n800, kinematic viscosity at 100 ° C. 20 cSt, [η] 0.04 dl
/ g, Q value 1.4, σ value 0.1 or less) and poly α-olefin oligomer (PAO-40, Mobil Chemical Co., SHF-40
1, product name, kinematic viscosity at 100 ℃ 40cSt),
Lubricating oils were prepared with the formulations shown in Table 3 and evaluated. However, as the extreme pressure additive, Angramol 99 (manufactured by Nippon Lugrisol Co., Ltd., trade name) was used.

Comparative Example 9 Commercially available ISO VG220 grade industrial gear oil was evaluated by the same method.

 The above results are summarized in Table 3.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C10M 105: 32 C10M 105: 32 159: 12 159: 12 143: 08 143: 08 143: 02) 143 : 02) C10N 20:02 C10N 20:02 20:04 20:04 30:08 30:08 30:10 30:10 40:04 40:04 40:08 40:08 70:00 70:00

Claims (2)

(57) [Claims] (A) 50 to 99.8 parts by weight of at least one base oil selected from synthetic hydrocarbons and esters having a kinematic viscosity of 1 to 20 cSt at 100 ° C, and (B) a kinematic viscosity of 100 to 10,000 cSt at 100 ° C. , The intrinsic viscosity [η] in decalin at 135 ° C is 0.5 dl / g or less, the number average molecular weight measured by gel permeation chromatography is 2000-7800, and the Q value measured by gel permeation chromatography (weight average (Molecular weight / number average molecular weight) is 4 or less, and standard deviation σ of ethylene composition
A lubricating oil composition containing 0.2 to 50 parts by weight of one or more thickening agents selected from ethylene / α-olefin cooligomers of 0 to 3. 2. The lubricating oil composition according to claim 1, wherein the α-olefin has 3 to 20 carbon atoms.