JPH04209697A - Automatic transmission oil composition - Google Patents

Abstract

PURPOSE:To provide an automatic transmission oil composition which is excellent in friction characteristics, nonfoamability, etc., and does not leak from breathers by incorporating a dimethylpolysiloxane specified in viscosity and a specific friction controlling agent in a base oil in respectively given amounts. CONSTITUTION:The title composition comprises a base oil, 0.01-5wt.% compound(s) selected from the group consisting of phosphoric (phosphorous) esters or amine salts, 8-30C aliphatic or aromatic carboxylic acids, reaction products with esters or organic amines of the above acids, hydrocarbon sulfides (e.g. diisobutyl disulfide) represented by the formula (wherein R<1> is a monovalent hydrocarbon group; R<2> is a divalent hydrocarbon group; X is an integer of 1 or more; (n) or 0 or 1 or more), and sulfurized fat or oil which is a reaction product of a fat or oil with sulfur, and 0.00003-0.005wt.% dimethylpolysiloxane having a viscosity at 25 deg.C of 50 to 500 thousand cSt.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to automatic transmission oil compositions.

[Prior art/issues to be solved by the invention] Automatic transmission oil compositions are required to have excellent various performances such as friction properties, oxidation stability, and antifoaming properties. In order to meet the requirements, various additives are added to the base oil depending on the purpose.

Incidentally, in recent years, there has been a remarkable trend toward smaller automatic transmissions and multi-speed transmissions in order to save fuel and improve drivability, but the downside of automatic transmissions being smaller and multi-speed is that the shock when changing gears becomes larger. There is a tendency to increase. Therefore, there is a need for an automatic transmission oil that reduces shift shock and improves riding comfort. The automatic transmission oil with a small shift shock has its friction characteristics, especially the ratio of the static friction coefficient (μ0) to the dynamic friction coefficient (μd) (μ0/μd).
is required to be as close to 1.0 as possible, and for this purpose, it has conventionally been common practice to add a friction modifier in addition to the anti-wear agent and the extreme pressure agent. However, adding a friction modifier may have an adverse effect on the antifoaming properties of automatic transmission oil. In particular, the recent miniaturization of automatic transmissions and the increase in engine output and speed have a tendency to raise the temperature of the oil in automatic transmissions. This causes a problem in that it promotes deterioration of the defoaming property of the oil and reduces the possibility of oil leakage from the breather of an automatic transmission, especially at high temperatures. Moreover, this problem tends to become more pronounced in degraded oils after long-term use.

Dimethylpolysiloxane, which has a viscosity of about 5,000 to 10,000 centistokes at 25°C, has traditionally been added as an antifoaming agent, but even if automatic transmission oil containing this low molecular weight dimethylpolysiloxane is used, It is difficult to suppress oil leakage of automatic transmission oil used in recent small automatic transmissions.

The present invention is an automatic transmission that incorporates a friction modifier to reduce shift shock, which prevents automatic transmission oil from leaking from the breather even when operated at high oil temperatures, and which deteriorates over long periods of use. The purpose of this invention is to develop an automatic transmission oil composition that is less likely to cause oil leakage even when the oil is contaminated.

[Means for Solving the Problems] The present invention uses dimethylpolysiloxane having a viscosity of 50,000 to 500,000 centistokes at 25° C. as a base oil.
os ~ 0.005% by weight, and (B) the following (1) to (5)
One or more compounds selected from the group consisting of 0.01 to 5
% by weight.

(1) Phosphate, phosphite, or amine salt thereof; (2) Saturated or unsaturated aliphatic carboxylic acid or aromatic carboxylic acid having 8 to 30 carbon atoms; (3) the above (2) or a reaction product of the carboxylic acid and an organic amine, (4) general formula (I): % formula % () (wherein R is a monovalent hydrocarbon group, R2 is a divalent A hydrocarbon sulfide represented by a hydrocarbon group, X is an integer of 1 or more, each X may be the same or different in the repeating unit, and n represents O or an integer of 1 or more. , (5) Sulfurized fats and oils are reaction products of fats and oils and sulfur.

[Function and Examples] In the present invention, 0.00% dimethylpolysiloxane having a viscosity at 25° C. of about 50,000 to 500,000 centistokes is added to the base oil together with the compound of component (B) used as a friction modifier.
By adding 03 to 0.005% (wt%, same hereinafter), it reduces the shock of gear shifting and prevents oil leakage when operating at high oil temperatures, not only with new oil but also with deteriorated oil. Unexpected effects are produced by the combined use of low-viscosity dimethylpolysiloxane and the friction modifier known from .

The dimethylpolysiloxane component (A) used in the composition of the present invention has a viscosity at 25°C of about 50,000 to 500,000 centistokes, preferably about 50,000 to 300,000 centistokes. If the viscosity of dimethylpolysoloxane is less than the above range, the antifoaming effect at high temperatures will be low, which is not preferable. If the viscosity exceeds the above range, dispersion into the base oil becomes difficult. The dimethylpolysiloxane has a ratio of about 0.0% to the base oil.
0003-0.005%, preferably about o,ooi~0
．． It is blended at a ratio of 0.003%. If the amount of dimethylpolysiloxane exceeds the above range, it will not be well dispersed in the base oil, and if it is less than the above range, the oil leak prevention properties, especially in degraded oil, will deteriorate. 25°C as long as a predetermined amount of the high viscosity dimethylpolysiloxane is added.
Antifoaming agents such as dimethylpolysiloxane having a viscosity of less than about 50,000 centistokes, ester type, fluorine type, etc. can be added in combination.

In the composition of the present invention, in addition to the dimethylpolysiloxane, one or more compounds selected from the group consisting of the following (1) to (5) are added as component (B).

(1) Phosphate ester, phosphite ester or amine salt thereof; (2) Saturated or unsaturated aliphatic carboxylic acid or aromatic carboxylic acid having 8 to 30 carbon atoms; (3) Carboxylic acid of (2) above. ester of an acid or a reaction product of the carboxylic acid and an organic amine, (4) general formula (I
): Hydrocarbon sulfide represented by the % formula %() (in the formula, R, R-, xsn are the same as above), (5) Sulfurized fat and oil which is a reaction product of fat and oil and sulfur.

The compounds (1) to (5) above are specific additives selected from additives that are generally called oil agents, anti-wear agents, extreme pressure agents, etc. Ratio of friction coefficient (μ0) to dynamic wear coefficient (μd) (μ0/μd)
This has the effect of reducing the shift shock by bringing the value closer to 1.0.

The phosphoric acid ester and phosphorous acid ester of component (1) (B) may be mono-, di-, or triester, and the alcohol residue thereof may be an alkyl group having 4 to 30 carbon atoms, such as butyl, octyl, lauryl. Examples include aryl groups having 6 to 30 carbon atoms, such as , stearyl, and oleyl groups; and alkyl-substituted aryl groups having 7 to 30 carbon atoms, such as phenyl group, such as methylphenyl, octylphenyl, and the like. Examples of specific compounds include tributyl phosphate, monooleyl phosphate, dioctyl phosphate,
Examples include dioleyl phosphite, diphenyl phosphite, and tricresyl phosphate.

Examples of the amine salts of phosphate esters and amine salts of phosphite esters of component (B) (1) include stearylamine salts, oleylamine salts, coconut amine salts, etc. of the phosphoric esters or phosphite esters. It will be done.

The saturated or unsaturated carbon number of the component (B) (2) is 8 or more
Examples of the 30 aliphatic carboxylic acids include capric acid, stearic acid, oleic acid, linoleic acid, linuric acid,
Erucic acid and the like, and the aromatic carboxylic acids include
Examples include benzoic acid and salicylic acid.

Among the component (B) (3), the carboxylic acid ester of (2) is the saturated or unsaturated carboxylic acid having 8 to 8 carbon atoms.
30 alkyl esters of aliphatic or aromatic carboxylic acids, such as butyl, octyl, lauryl,
Examples include stearyl and oleyl ester. Examples of specific compounds include oleyl caprate,
Examples include octyl valmitate, amyl stearate, lauryl oleate, and lauryl linoleate.

Of the component (B) (3), the reaction product of the carboxylic acid of (2) and the organic amine is the saturated or unsaturated aliphatic carboxylic acid or aromatic carboxylic acid having 8 to 30 carbon atoms. and alkanolamines such as monoethanolamine, motuprobanolamine, jetanolamine, dibrobanolamine, diisopropanolamine, triethanolamine, polymethylene polyamines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, Examples include reaction products with tetrapropylene pentamine, hexabutylene hebutamine, hexaethylene hebutamine, heptaethylene octaamine, and the like.

The hydrocarbon sulfide represented by the formula (+) of component (4) (B) is a hydrocarbon group in which R1 is a monovalent hydrocarbon group, such as an alkyl group or an alkenyl group having 2 to 20 carbon atoms.
straight-chain or branched, saturated or unsaturated aliphatic hydrocarbon group, or aromatic hydrocarbon group having 6 to 2B carbon atoms;
-20 linear or branched aliphatic hydrocarbon groups, or aromatic hydrocarbon groups having 6 to 26 carbon atoms.

Specific examples of the hydrocarbon group represented by R1 include ethyl group, propyl group, butyl group, nonyl group, dodecyl group, propenyl group, butenyl group, phenyl group, tolyl group, hexylphenyl group, benzyl group, etc. .

Specific examples of the divalent hydrocarbon group represented by R2 include:
Examples include ethylene group, propylene group, butylene group, and phenylene group.

Representative examples of compounds of the hydrocarbon sulfide represented by the general formula (I) include sulfurized olefins and R'-Sx-R' in the case where X is 2 or more and n is 0 in the general formula (1).
It is a polysulfide compound represented by

Specific examples of these hydrocarbon sulfides include diisobutyl disulfide, dioctyl polysulfide, ditertiary nonyl polysulfide, ditertiary butyl polysulfide, dibenzyl polysulfide, and sulfurizing agents such as olefins such as polyisobutylene and terpenes. Examples include sulfurized olefins sulfurized with sulfur, a reaction product of isobutylene and sulfur, and a compound estimated to have the formula: (wherein x and n are the same as above).

The sulfurized fat and oil of component (5) (B) is a reaction product of fat and oil and sulfur, and the fat and oil include lard, beef tallow, whale fat,
There are animal and vegetable oils such as palm oil, coconut oil, and rapeseed oil.

This reaction product does not have a single chemical structure but a mixture of various substances, and the chemical structure itself is not clear.

The friction modifier, which is the component (B), has a content of about 0 relative to the base oil.
．． It is used in a range of about 0.01 to 5%, preferably about 0.1 to 3%. If the amount of the friction modifier is less than the above range, there will be no effect, and if it exceeds the above range, it will adversely affect the antifoaming properties and oxidation stability of the composition, which is not preferred.

The composition of the present invention has a μOlμd of about 0.92 to 1.05 by adding the component (B) as the friction modifier in the above ratio.
It is preferable to keep it within the range of 1.0, and more preferably as close to 1.0 as possible.

The composition of the present invention may further include metal detergents, ashless dispersants, antioxidants, corrosion inhibitors, pour point depressants, viscosity index improvers, seal swelling agents, etc. that are commonly added to automatic transmission oils. may be added.

Examples of the metal type detergent include alkaline earth metal sulfonates and alkaline earth metal phenates.

Examples of the ashless dispersant include alkenyl succinimides, alkenyl succinic esters, amides of long chain fatty acids and polyamines (amino amide type), and the like.

Examples of the antioxidant include amine type antioxidants, phenolic type antioxidants, zinc dithiophosphate, and the like.

Examples of the corrosion inhibitor include benzotriazole and alkenyl succinate.

Examples of the pour point depressant include a condensate of chlorinated paraffin and naphthalene, a condensate of chlorinated paraffin and phenol, polymethacrylate, polybutene, polyalkylstyrene, and the like.

Examples of the viscosity index improver include polymethacrylates and olefin copolymers.

Examples of the seal swelling agent include esters such as phosphoric acid esters and dioctyl phthalate.

The amount of each of these additives used is preferably about 0.01 to 10% of the automatic transmission oil composition, and when various additives are used together, the total amount is about 0.1 to 20%. is preferable.

As the base oil for the automatic transmission oil used in the present invention, oils that have conventionally been generally used as base oils for automatic transmission oils can be used;
centistokes, preferably about 1.5 to 10 centistokes mineral oil (mineral lubricating oil or its refined product);
Particular preference is given to synthetic oils (lubricating oils) alone or in mixtures.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these.

Examples 1 to 10 and Comparative Examples 1 to 5 Automatic transmission oil compositions were prepared by using refined mineral oil with a viscosity of 3.6 centistokes at 100° C. as the base oil and blending it with the additives shown in Table 1. did.

Regarding the obtained composition, antifoaming properties of new oil and deteriorated oil,
Friction characteristics, bench breather oil leakage tests, and actual vehicle high-speed durability tests were conducted. The test conditions for each are as follows.

The deteriorated oil was obtained by oxidative deterioration at 150° C. for 96 hours in accordance with JIS K-2514.

The antifoaming test was conducted in accordance with JIS K-2518, Petroleum Product Foaming Test Method, as shown below.

(1) Heat 200ml of sample oil to 49±3°C, then cool to 24±3°C.

(2) Take 190 ml of the sample oil obtained in (1) above in a container, place it in a water bath maintained at 24±0.5°C, insert an air introduction tube with a diffuser stone into the container, and hold for about 5 minutes.

(3) After the first bubbles appear, blow dry air at a flow rate of 94±5 ml/win for 5 minutes.

(4) Stop ventilation and immediately read the amount of bubbles.

The amount of foam at this time is defined as foaming amount I.

(5) After that, leave it for 10 minutes and read the amount of bubbles.

The amount of foam at this time is defined as foaming amount 11.

(Foaming amount) Seq I Foaming amount I in Nistep (4),
The amount of foaming (11) in (5) is expressed as I/II.

5eqll: After completing the Seq I test, the sample was further subjected to step (1) in a water bath at 93.5±0.5°C.
, (4), and (5) are repeated to obtain the foaming amount I and the foaming amount I+, which are expressed as I/I+.

5eqlll: After completing the 5eqll test, the sample was allowed to cool down to 24°C or lower in the air, placed in a water bath at 24±0.5°C again, and the steps (3), (4), and (5) were repeated. , foaming amount I
and foaming amount II are obtained and displayed as I/11.

The friction properties were tested using an SAE No. 2 (manufactured by Shinko Zoki) friction tester under the following conditions.

Disc: Vapor material disc (2 pieces) Plate: Steel plate (3 pieces) Surface pressure: 20 Kgf/cd Oil temperature: 120 ℃ Motor rotation speed: Dynamic friction coefficient when the rotation speed is 1200 rpm under experimental conditions of 3000 rpm mark or higher is μd , the coefficient of static friction when stopping is μ0
Then, μ0/μd was calculated.

The bench breather oil leakage test was conducted under the following conditions.

Range: D3 Oil level: Upper limit +10mm Input rotation speed: 8000rpa+ Oil temperature (oil pan): Initially 80°C, cooling was stopped, and the temperature was raised until oil leakage occurred.

An oil temperature of 140'C or higher at which oil leakage occurred under the above conditions was considered to be a pass.

The actual vehicle high-speed durability test was conducted under the following conditions.

Vehicle speed: 135 ~ 140) cm/hm/
Level: Upper limit +10111! l Oil temperature: 110 to 120°C Judgment 2 The test results are shown in Table 2 based on the mileage until oil leakage occurs.

[See the following margins] From the results of Examples 1 to IO1 and Comparative Examples 1 to 5, the following is understood. In other words, the automatic transmission oil composition containing the dimethylpolysiloxane of the present invention in combination with a specific compound as a friction modifier has excellent frictional properties and antifoaming properties, and has an antifoaming effect even in degraded oil at high oil temperatures. However, oil leakage is also prevented. On the other hand, even if conventionally used low-viscosity dimethylpolysiloxane is used in combination with a friction modifier, the effect of preventing foaming of deteriorated oil is small and oil leakage is likely to occur at high temperatures.

[Effects of the Invention] As described in detail above, the automatic transmission oil composition of the present invention has excellent frictional properties and generates little foaming even during operation at high oil temperatures, so oil leakage from the breather can be prevented. Furthermore, since the above-mentioned excellent characteristics are maintained even with degraded oil, the oil can be sufficiently adapted to miniaturization of automatic transmissions.

Claims (1)

[Claims] 1. (A) 0.0003 of dimethylpolysiloxane having a viscosity of 50,000 to 500,000 centistokes at 25°C is added to the base oil.
~0.005% by weight; and (B) 0.01 to 5% by weight of one or more compounds selected from the group consisting of (1) to (5) below. Composition. (1) Phosphate, phosphite, or amine salt thereof; (2) Saturated or unsaturated aliphatic carboxylic acid or aromatic carboxylic acid having 8 to 30 carbon atoms; (3) (2) above. (4) General formula (I): ▲There are numerical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R^1 is 1 a valent hydrocarbon group, R^2 is a divalent hydrocarbon group, x is an integer of 1 or more, each x may be the same or different in the repeating unit, and n
(represents an integer of 0 or 1 or more); (5) Sulfurized fats and oils that are reaction products of fats and oils and sulfur.