JPH0813981B2 - Automatic transmission oil composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic transmission oil composition.

(Prior Art) Conventional automatic transmission fluids include oils such as ATF dexylone.

(Problems to be solved by the invention) However, in such a conventional automatic transmission fluid, the high temperature viscosity is about 7 cSt at 100 ° C, about 4 cSt at 140 ° C,
Also, since the low temperature viscosity is 4,000 cp at -30 ° C, the oil temperature is 1
If the temperature rises to 40 ° C, the pump efficiency will drop somewhat due to leakage due to low viscosity, and if the oil temperature drops to -30 ° C, the viscosity (increase in viscosity) will cause the automatic transmission selection (from neutral to drive) time lag. There was a problem of getting bigger.

(Means for Solving Problems) The inventor has found that the high temperature viscosity of oil is 7 cSt or more at 140 ° C., the low temperature viscosity is 2,900 cP or less at −30 ° C., and the shear stability in order to ensure excellent durability. (ASTM D 2603 sound wave 28 μm, irradiation for 60 minutes) at 100 ° C viscosity reduction rate of 10% or less, and by setting the flash point to 155 ° C or more for fire prevention, it was confirmed that the above problems could be solved. The invention has been achieved.

Therefore, the automatic transmission oil composition of the present invention has a C _{14 to} C ₂₆ α-
Olefin oligomer 69-89% by weight, number average molecular weight 3,
000-4,000 ethylene-α-olefin oligomers 10-
25% by weight and ethylene having a number average molecular weight of 26,000 to 40,000
1 to 4% by weight of α-olefin copolymer and / or neopentyl glycol fatty acid ester (C of fatty acid is 6 to
10) 0.1-9% by weight.

Hereinafter, the automatic transmission oil composition according to the present invention will be described.

The composition of the present invention comprises [1] 69 to 89% by weight of C _{14 to} C ₂₆ α-olefin oligomer, and [II] number average molecular weight of 3,000 to
4,000 ethylene / α-olefin oligomers 10-25
% Of ethylene- [alpha] -olefin copolymer having a number average molecular weight of 26,000 to 40,000 and / or [IV] neopentyl glycol fatty acid ester (C of fatty acid is 6 to 10).

Further, the composition of the present invention may optionally contain an additive as a fourth component [V] in a proportion of 0.1 to 10% by weight.

The components [I] to [V] will be described more specifically.

[I] C ₁₄ -C ₂₆ α-Olefin Oligomer The α-olefhen oligomer is a dimer of 1-decene,
Alternatively, it is a mixture of oligomers having 14 to 26 carbon atoms centered on this. If the carbon number is smaller than this range, the flash point becomes low, and if it is larger than this range, the low temperature viscosity becomes too high, which is not preferable.

The proportion of the α-morefin oligomer in the automatic transmission oil is 69% by weight or more and 89% by weight or less. If it is smaller than this range, the low temperature viscosity becomes too high, and if it is larger than this range, the high temperature viscosity becomes too low, which is not preferable.

[II] Ethylene / α-olefin oligomer having a number average molecular weight of 3,000 to 4,000 The ethylene / α-olefin oligomer is equivalent to Lucant HC-2000, a product of Mitsui Petrochemical Industry Co., Ltd., and has a number average molecular weight of about 3,500. , 3,000 to 4,000 are also included.

The proportion of the ethylene / α-olefin oligomer in the automatic transmission fluid is 10% by weight or more and 25% by weight or less.
When it is smaller than this range, the high temperature viscosity becomes insufficient, and when it is larger than this range, the low temperature viscosity becomes too high, which is not preferable. When the ethylene-α-olefin copolymer is not used, the blending amount of the ethylene-α-olefin cooligomer is preferably in the range of 18 to 25% by weight.

(III) number average molecular weight 26,000 ~ 40,000 ethylene
The olefin copolymer, which is a copolymer of ethylene and α-olefin like the co-oligomer, has a large number average molecular weight of 26,000 to 40,000 and serves as a viscosity index improver.

When the ethylene / α-olefin copolymer is blended, the proportion of the automatic transmission oil is 1% by weight or more and 4% by weight or more.
It is the following. If it is less than this range, the target viscosities at high temperature and low temperature cannot be secured at the same time, and if it exceeds this range, the shear stability is insufficient and the effect of addition cannot be found.

[IV] Neopentyl glycol fatty acid ester The neopentyl glycol fatty acid ester is a mixture of caprylic acid diester or a fatty acid ester having 6 to 10 carbon atoms with the fatty acid ester being the center. These esters play a role of appropriately swelling the non-metallic material which is contracted by the hydrocarbon oil.

The proportion of the ester in the automatic transmission oil is 0.1% by weight or more and 9% by weight or less. If it exceeds this range, the low temperature viscosity becomes too high to secure the target viscosity at high temperature, which is not preferable.

[V] Additive In the automatic transmission oil composition of the present invention, if necessary, at least one kind of an antioxidant, an antiwear agent, an oiliness agent, a detergent dispersant, an antifoaming agent, etc. may be added. it can.

Details of the various additives are introduced in, for example, “Petroleum Product Additives” by Toshio Sakurai (Koshoubo), and the examples are shown below.

Antioxidants include zinc dialkyldithiophosphate, 2,
6-di-tert-butylparacresol and the like can be added in an amount of 0.1 to 3.0% by weight.

0.1-5% by weight of phosphoric acid ester, metal salt of dithiophosphoric acid, etc. as an antiwear agent, 0.5-6% by weight of fats and oils, higher fatty acids, etc. as an oiliness agent, Mg sulfonate, polybutenyl succinimide as a detergent dispersant. 0.1 to 4% by weight, and antifoaming agents such as silicone and ester 0.002
~ 0.5 wt% each can be added.

When these various additives are used in combination, the total amount thereof is preferably 0.1% by weight or more and 10% by weight or less based on the automatic transmission oil composition.

The automatic transmission composition of the present invention has an oil high temperature viscosity of 140
7cSt or higher at ℃, low temperature viscosity of ≤ 2,900cp at -30 ℃, and shear stability (ASTM D26
03 Sound wave 28 μm, 60 minutes irradiation) 10% at 100 ° C viscosity reduction rate
It also satisfies the condition that the flash point is 155 ° C or higher for fire prevention, and the performance at high and low temperatures is further superior to that of ATF that is currently generally used. High temperature for example
At 140 ° C, the pump efficiency of the composition of the present invention (viscosity of about 7 cSt) is about 25%, compared to commercially available ATF (viscosity of about 4 cSt).
high. Further, at a low temperature of -30 ° C, the composition of the present invention (viscosity of about 2,800 cps) was used against commercially available ATF (viscosity of about 4,000 cp).
cp) can reduce the automatic transmission selection (neutral to drive) time lag by about 1-2 seconds. Furthermore, since the shear stability is extremely good, the high temperature and low temperature performances do not change even after the endurance.

(Examples) Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

The compositions of Examples 1 to 6 in Tables 1 and 2 are the automatic transmission oil compositions of the present invention, and the compositions of Comparative Examples 1 to 6 are comparative compositions. Numerical values of the oil composition and additives in the table are shown in% by weight.

 The additives used are as follows.

The antioxidant was 2,6-di-tert-butylparacresol in Example 5 and Comparative Examples 1 and 4, and zinc dialkyldithiophosphate in Examples 2 and 6, and Comparative Examples 2, 3, 5 and 6.

All the antiwear agents were phosphorus-based commercial antiwear agents, the oiliness agents were Example 5, Comparative Examples 1 and 4 were fats and oils, and Examples 2 and 6 and Comparative Examples 2, 3, 5 and 6 were C ₁₄ -C ₁₈ fatty acids. The detergent / dispersant is a mixture of magnesium sulfonate and polybutenyl succinimide.

 All antifoam agents are silicone.

The compositions of Examples 1-2 and 3-6 and Comparative Examples 1-
Tested various performances on compositions 3 and 4-6,
The results of the compositions of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in Table 1, and the results of Examples 3 to 6 and Comparative Examples 4 to 6 are shown in Table 2. The test method is as follows.

(1) Viscosity (140 ° C): Measured according to JIS K2283. It is preferably 7 cSt or more.

(2) Viscosity (−30 ° C.): Measured by ASTM D2983. 2,900cp
The following is preferred.

(3) Shear stability: A sound wave having an amplitude of 28 μm was irradiated for 60 minutes by ASTM D 2603, and the viscosity decrease rate at 100 ° C. was measured. It is preferably 10% or less.

(4) Flash point: Measured according to JIS K 2265.

 It is preferably 55 ° C or higher.

Examples 1 and 2 Reference examples and 2 are dimers of 1-decene, ethylene-α
-Compositions before and after adding various additives to the mixed oil of the olefin cooligomers, Examples 1 and 2 are compositions in which the neopentyl glycol caprylic acid diesters of Reference Examples 1 and 2 were further added. All passed various tests, and it was revealed that they were excellent automatic transmission fluid compositions.

Comparative Examples 1 to 3 Comparative Examples 1 and 2 are 1-decene dimer, ethylene-
An example in which various additives are added to a mixture of α-olefin cooligomers, Comparative Example 3 is an example of a composition in which neopentyl glycol caprylic acid diester is added to the components of Comparative Example 2, and ethylene and 1- When the low temperature viscosity is kept low when the α-olefin cooligomer is low, the high temperature viscosity becomes low, and when a large amount of the ethylene-α-olefin cooligomer of 2 is added, the low temperature viscosity becomes too high. It is not preferable compared to the examples.

Examples 3-6 Examples 3 and 5 are dimers of 1-decene, ethylene-
Compositions before and after blending various additives into a mixed oil of an α-olefin cooligomer and an ethylene-α-olefin copolymer. A composition further containing a diester, each of which passed various tests,
It has been found to be an excellent automatic transmission oil composition.

Comparative Examples 4 to 6 Comparative Examples 4 and 6 were prepared by adding no viscosity index improver.
If the low temperature viscosity is kept low, the high temperature viscosity becomes low, and if the high temperature viscosity is kept high, the low temperature viscosity becomes too high. Also,
Comparative Example 5 is a case where a large amount of the viscosity index improver was added,
The low temperature viscosity becomes high and the shear stability becomes poor. Any of the comparative examples is not preferable as compared with the examples.

The shear stability of Examples 1 to 2 is higher than that of Examples 3 to 6.
The viscosity decrease rate at 100 ° C is as low as 2% or less. This is because the high-molecular-weight viscosity index improver (copolymer of ethylene-α-olefin having a large molecular weight) contained in Examples 3 to 6 is cut off to increase the rate of decrease in viscosity. This is because no. 2 contains no viscosity index improver.

(Effects of the Invention) As described above, according to the present invention, the composition is [I] C _{14 to} C ₂₆ α-olefin oligomer 69 to 89% by weight, and [II] the number average molecular weight is 3,000 to 4,000. Of ethylene-α-olefin cooligomers of 10 to 25% by weight, [II
I] 1 to 4% by weight of ethylene-α-olefin copolymer having a number average molecular weight of 26,000 to 40,000 and neopentyl glycol fatty acid ester of [IV] (C of fatty acid is 6 to 10).
Since it is an automatic transmission composition containing 1 to 9% by weight,
When the temperature of the automatic transmission oil rises to 140 ° C, the pump efficiency is improved, and when the temperature drops to -30 ° C, the automatic transmission select (neutral to drive) time lag can be improved. Further, it is possible to obtain the effect that the high temperature and low temperature performances do not change even after the endurance.

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Claims (1)

[Claims] 1. A C ₁₄ -C ₂₆ α-olefin oligomer 69-89
% Ethylene and ethylene with a number average molecular weight of 3,000 to 4,000
Olefin oligomer 10 to 25% by weight and number average molecular weight 2
An automatic transmission oil composition comprising 1 to 4 wt% of an ethylene-α-olefin copolymer of 6,000 to 40,000 and / or 0.1 to 9 wt% of a neopentyl glycol fatty acid ester (C of fatty acid is 6 to 10). Stuff.