JPH0339399A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To obtain the subject lubricating oil composition showing excellent characteristics against variation with time and temperature change by blending a base oil with a phosphoric or phosphorous ester (salt), an alkylamine compound, a perbasic magnesium sulfonat, etc. CONSTITUTION:With a base oil, (A) one or more selected from a phosphoric or phosphorous ester represented by formulae I-IV (l is 1-3; m and n are 1 and 2; R and R' are 4-30C alkyl and alkyl-substituted aryl) and amine salts thereof, (B) an alkylamine compound expressed by formula V (R'', R''' and R'''' are H, 1-30C alkyl, aryl, alkyl-substituted aryl or alkanol), (C) an aliphatic dicarboxylic acid compound, (D) succinicimide and (E) a perbasic magnesium sulfonate or a perbasic calcium sulfonate are blended, thus obtaining the objective composition. The resultant composition can be used as an automatic transmission oil, a wet type brake oil, of an automobile, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition for use in automatic transmissions, wet brake oils, etc., and particularly for automatic transmissions of automobiles.

[Conventional technology]

Conventionally, two types of lubricating oil (hereinafter also referred to as ATF) have been used for automobile automatic transmissions.

One is ATF, which contains a friction modifier (hereinafter also referred to as FM) in oil, and is typified by oil that satisfies GM's Dexron ■ standard. The other type is ATF that does not contain FM in the oil, and is typified by oil that satisfies Ford's M2C33F (Type F) standard.

Since the Type F ATF described above does not use FM, it has the disadvantage that it causes a large shift shock during shifting, which deteriorates the ride comfort of the automobile.

In addition, since the above-mentioned Dexron ■ type ATF uses FM, it has the characteristic that there is almost no gear shift stiffness during shifting, or even if there is, it is small, but this characteristic can be maintained because ATF is similar to new oil. When the oil deteriorates due to heat and oxidation, the FM is consumed and the shift shock becomes large.

On the other hand, in general, when the ATF oil temperature is low, for example when the vehicle has just started driving or when driving in a cold region, the shift shock is large even if the ATF is new oil. Various proposals have been made from the viewpoint of suppressing this type of shift shock. For example, in JP-A-60-173097, (A) trivalent and pentavalent phosphoric acid esters or their amines are added to the base oil. salt, and (B) sorbitan fatty acid ester, palm kernel oil fatty acid,
Coconut oil fatty acids (the first two are glycerin esters of higher fatty acids, i.e. oils and fats are the main ingredients), mixtures of oils and fatty acids, polyalkylene polyamines and fatty acids (
A lubricating oil composition has been proposed that contains one type of compound selected from the group consisting of:

Furthermore, JP-A No. 63-254196 discloses that phosphoric acid esters, phosphorous esters, phosphoric acid ester amine salts, carboxylic acids, carboxylic acid oxides, etc. are blended as FM with specific base oils. It is proposed that. Furthermore, FM consisting of a condensation product of an unsaturated fatty acid and an alkanolamine was proposed in JP-A No. 63-180000, and FM consisting of a condensation product of a fatty acid and a dialkanolamine was proposed in JP-A No. 63-66299. FM consisting of a combination with fats and oils has been proposed, and JP-A-62-84190 proposes blending magnesium sulfonate with base oil as a metal detergent.

Including these proposals, efforts are being made to obtain a stable lubricant for automobile automatic transmissions that does not cause shift shock over a long period of time, but in order to obtain a lubricant that is fully satisfactory, There is still room for improvement.

[Problem to be solved by the invention]

The present inventors have found that, among various additives used in automatic transmission lubricating oil (ATF), friction adjustment We conducted intensive studies from the viewpoint of the importance of controlling the selection of FM and its usage.

In order to prevent the FM in the ATF from being gradually consumed during use and resulting in shifting problems, it would be a good idea to add a large amount of FM from the beginning, but if too much FM is added, the friction coefficient will decrease. This is undesirable because the smaller the clutch, the more slippage occurs when the clutch is engaged and the shift time becomes longer, resulting in a slow response and engine revving due to poor response. Therefore, in order to solve the problem of shift shock due to FM wear, it is important to select an FM that is less likely to wear out under high-temperature operation and has excellent stability against heat and oxidation.

Furthermore, in order to solve the problem of shift shock when the ATF oil temperature is relatively low, it is important to use an ATF whose friction coefficient changes little with respect to temperature changes.

With the above in mind, the present inventors developed one or two types of FM that have strong adsorption activity at low temperatures, that is, improve friction characteristics at lower temperatures, and one that has strong adsorption activity at high temperatures, that is, at higher temperatures. Total of 2 of 1 type of FM that improves friction characteristics on the side
We have discovered that by combining ~3 types of FM, and furthermore a specific ashless dispersant and metal detergent, we can obtain an ATF that exhibits excellent characteristics against changes over time and temperature changes, and have developed the present invention. It was completed.

[Means to solve the problem]

According to the present invention, in order to solve the above problems, the following (iL (ii), (iiiL (iv) and (
v), or (i), (iii), (iv) and (v): (i) the following general formulas (1), (2), (3) and (4), (RO)r-P-( OH) 3-f
m (1) Seal (RO)T-P→OH)+-,・NIl,R'! −
--(2)(RO)y-P-i0H)3-1
... (3) (RO)7- P→0H)3
-, ・NH,R' 3-11 ++ (4) (In the above formula, l represents an integer of 1 to 3, m and n each represent an integer of 1 or 2, and R and R' are the same phosphoric acid esters, phosphite esters and their agonists represented by At least one salt selected from salts; (ii) the following general formula (5), (in the above formula, R″, Rr′p, and Rnrr are hydrogen atoms, C, to C3° alkyl groups, aryl groups, alkyl-substituted aryl group or alkanol group as shown in Table 17); (iii) an aliphatic dicarboxylic acid compound; (iv) succinimide; (v) overbased magnesium or calcium sulfonate; A lubricating oil composition is provided.

The first FM (i
Components) are represented by the general formulas (1), (2), (3) and (
4) At least one selected from phosphate esters, phosphite esters, and their amine salts, and this FM has strong adsorption activity on the low temperature side (adsorbs to the friction surface that causes friction and increases the friction coefficient between the two). (characteristics that lower the Specific compounds of this type include, for example, mono(R) phosphate, di(R) phosphate, where R is butyl, hexyl, octyl, decyl, lauryl, myristyl, palmityl, stearyl, oleyl, phenyl, cresyl, etc.
Phosphate esters such as phosphate and tri(R) phosphate; Phosphite esters such as mono(R) phosphite, di(R) phosphite, and tri(R) phosphite:
Di(R) phosphate mono(R′) amine salt, mono(R
) Phosphate ester amine salts such as phosphate di(R') amine salts; phosphite ester amine salts such as mono(R) phosphite amine salts;

Next, the second FM constituting the lubricating oil composition i of the present invention
(The acid component (ii) is composed of an alkyl pentane compound represented by the general formula (5) above, and this FM (ii) component also has strong adsorption activity on the low temperature side (adsorbs to the friction surface that generates friction, causing a gap between the two). (characteristics that lower the coefficient of friction).

In formula (5), two or three of RrtRDI and Rn" may be the same or completely different.
To illustrate Rrp, Rrrz, and R′r, C3
-C5° Alkyl groups, alkyl-substituted aryl groups, alkanol groups such as ethanol groups and propanol groups. However, from the viewpoint of solubility in oil, at least 1
Desirably, the type is an alkyl group or an alkyl-substituted aryl group having a chain length of 04 or more. The following are exemplified as specific compounds of the component (ii).

(a) Heptamines Examples include butylamine, pentylamine, hexylamine, octylamine, laurylamine, octadecylamine, oleylamine, stearylamine, and the like.

(b) Diamines such as dibutylamine, dipentylamine, dihexylamine, dioctylamine, dilaurylamine, dioctadecylamine, distearylamine, stearylamine,
Monoethanolamine, palmityl monopropanolamine, decyl monoethanolamine, hexyl monopropanolamine, phenyl monoethanol ξ
Examples include tolyl monopropanol amine, tolyl monopropanol amine, and the like.

(c) Triamines such as tributylamine, tribentylamine, trihexylamine, trioctylamine, trilaurylamine, triotadecylamine, trioleylamine,
Tristearyl amine, dioleyl monoethanolamine, dilauryl monopropanolamine, dioctyl monoethanolamine, dihexyl monopropanolamine, dibutyl monopropanolamine, oleyl jetanolamine, stearyl dibro Banolamine, lauryl jetanolamine, octyl
dibrobanolamine, butyl jetanolamine,
Examples include phenyl jetanolamine, tolyl dibrobanolamine, xylyl jetanolamine, jetanolamine, and dibrobanolamine.

Next, the third FM (i
ii) component is an aliphatic dicarboxylic acid compound, and this FM
The components exhibit strong adsorption activity at high temperatures. Specific compounds of this type include adipic acid, pimelic acid,
Speric acid, azelaic acid, sebacic acid, undecanniic acid (brassylic acid), dodecanniic acid, tetradecanniic acid,
There are esterification reaction raw materials such as octadecanoic acid, icosanniic acid, triacontannic acid, etc., and these dicarboxylic acids or their anhydrides with diethylene glycol, thiodiethylene glycol, or monoalkylene glycol.

FM ((i)+(ii)) in the lubricating oil composition of the present invention
The amount of +(iii) or (i)+(iii)) added is:
0.01~2. Owt%, preferably 0.05-1.
Owt% is blended. FM if less than 0.01wt%
If the content exceeds 2.0 wt%, as mentioned above, too much FM will be applied and slippage will increase when the clutch is engaged, which is not preferable.

Further, in the lubricating oil m paraboloid of the present invention, the FM ((
The mixing ratio of the i)+(ii)) component and the FM (iii) component is effective in a wide range of to: 90 to 90: 10% by weight, but it is used at a ratio of 25: 75 to 75: 25% by weight. is effective. Furthermore, the F
The mixing ratio of M(i) component and FM(ii) component is 10:
It is effective in a wide range of 90 to 90:10% by weight, but
It is effective to use it in a ratio of 25:75 to 75:25% by weight. -, FM(i) component and FM(iii)
) components, the mixing ratio is 20:80-80
: Effective in a wide range of 20% by weight, but 40% by weight:
60-60: It is most effective to use it at a ratio of 40% by weight.

Next, the blending of a specific ashless dispersant, which is a feature of the present invention, will be explained.Usually, an ashless dispersant is blended in this type of lubricating oil, but in the present invention, while maintaining sludge dispersibility, Furthermore, it has been found that addition of succinimide is suitable as a compound that also improves friction properties.

Although the reason for the friction property improvement effect of succinic acid is not clear, it is speculated as follows.

Succinimide causes competitive adsorption with FM on the friction surface, controls the adsorption state of FM, and increases the initial μS (static friction coefficient) and μ0 (final W! friction coefficient)/μd (dynamic friction coefficient). We believe that this results in stable friction characteristics.

Examples of this succinimide compound include the following. That is, mono- and bis-alkyl succinimides represented by the following general formula (in the above formula, R represents an oligomer residue with a molecular weight of about 1000, and n represents an integer of 4 to 6) and B-shielded succinimides. etc. Among these, B-shielded succinimide is particularly preferred.

In addition, the amount of component (iv) added is 1.00 to 10.00w.
It is preferably t%, and more preferably 2.00 to 5.00wt%. If the amount added is less than 1.00 wt%, the dispersibility of degraded substances is poor and μS decreases due to FM adsorption. If it exceeds 10.00 wt%, μ0/μd decreases due to FM adsorption interference, resulting in poor friction characteristics and further deterioration in wear resistance.

Furthermore, the formulation of a specific metal detergent, which is a feature of the present invention, will be explained.Normally, a metal detergent is blended in this type of lubricating oil, but in the present invention, while maintaining cleanliness, It has been found that the incorporation of overbased sulfonates is suitable as a composition for improving friction properties.

Although the reason for the effect of overbased sulfonate on improving friction properties is not clear, it is presumed as follows. Some sulfonates are neutral or basic, but overbased sulfonates are thought to control the adsorption state of FM due to their strong basicity, have the effect of increasing μd (coefficient of kinetic friction), and even increase the multiplier. This has the effect of lowering μ0 (final coefficient of friction)/μd, which is an index of comfort (occurrence of shift shock).

Examples of overbased sulfonate compounds include the following. That is, examples include overbased magnesium sulfonate and overbased calcium sulfonate.

Here, overbase number is TBN (TOTAL BASE
NIIMBER) indicates 300 or more.

(v) The amount of component added is 0.05 to 1.000%, especially 0.
．． Preferably 10 to 0.50 t%, 0.0
If it is less than 5 wt%, the cleanliness will be poor, and if it exceeds 1.00 wt%, the abrasion resistance will be poor. Further, when the above specific ashless dispersant and metal detergent are combined and blended, a synergistic effect on the friction properties can be obtained.

In the lubricating oil composition of the present invention, mineral oils and synthetic oils known in the art are used as the base oil to which the above-described components are added.

Mineral oils include 60 neutral oil, 100 neutral oil, 150 neutral oil, 300 neutral oil, 500 neutral oil, which are obtained by solvent refining or hydrogenation refining.
There are also low pour point base oils whose low temperature fluidity has been improved by removing the wax content from these base oils, and these can be used alone or as a mixture in an appropriate proportion.

In addition, synthetic alcoholic beverages include polyα-olefin oligomers,
These base oils include diesters, polyol esters, polyglycol esters, etc. These base oils are usually used alone, but can also be used in combination with the mineral oils mentioned above.The mixing ratio of synthetic oil and mineral oil is, for example, 80: 20-20
: 80.

In the present invention, the viscosity of the base oil described above is 1o.

3 to 20 cSt at °C is preferred.

The lubricating oil composition of the present invention includes an anti-wear agent selected from -grade zinc thiophosphate, secondary zinc thiophosphate, zinc allylthiophosphate, etc., particularly preferably primary zinc thiophosphate, and further includes a viscosity index improver and an antioxidant. etc. may be contained.

[Examples] Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited to these Examples in any way.

<Examples 1 to 4/Comparative Examples 1 to 4> As shown in Table 1 below, FM as a friction modifier
(i), (ii) and (iii) components (total 0.
5wt%), and the remaining amount of base oil (refined mineral oil, 4.Oc.
Test oils were prepared using a 100° C.

The friction properties of the test oil thus prepared were measured using a 5AENα2 friction tester manufactured by Automax Co., Ltd. (Japan).

This test consists of a dynamic test and a static test, and from the torque curve obtained in each test, the torque value Td (dynamic 11! friction torque), To (final friction torque),
Determine Ts (static friction torque) and use the following formula % formula % (1) The corresponding friction coefficient μd (dynamic friction coefficient) and μ0 (
final friction coefficient) and μS (static friction coefficient) were calculated.

From Table 1, the ATF of the present invention, that is, the FM that has excellent stability against heat and oxidation and exhibits strong adsorption activity at low temperatures.
An ATF prepared by combining an appropriate amount of an acid component and an FM acid component that exhibits adsorption activity on the high-temperature side, as well as a specific ashless dispersant and metal detergent, was tested for friction properties using a 5AEk2 tester. It can be seen that the coefficient of friction is stable with little change over time, and that the coefficient of friction is also stable when measured at different oil temperatures.

C Effects of the Invention The lubricating oil composition of the present invention has excellent properties in that the coefficient of friction changes little over time and is stable, and the coefficient of friction changes little with changes in oil temperature. Therefore,
It is particularly useful as a lubricant for automatic transmissions in automobiles, and in actual vehicle shift shock sensitivity tests, it suppresses shift shock during shifts and provides extremely good ride comfort.

Claims (1)

[Claims] 1. The base oil contains the following (i), (ii), (iii), (i)
v) and (v), or (i), (iii), (iv
) and (v): (i) The following general formulas (1), (2), (3) and (4)
, ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(2) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(3) ▲ There are mathematical formulas, chemical formulas, tables, etc.▼...(4) (In the above formula, l represents an integer of 1 to 3, m and n each represent an integer of 1 or 2, and R and R' are the same. They may be present or different, and C_4 to C_3_ respectively.
0 alkyl group, aryl group, or alkyl-substituted aryl group); (ii) the following general formula (5), ▲ formula , chemical formulas, tables, etc.▼...(5) (In the above formula, R'', R''', R'''' are hydrogen atoms, C_1~
C_3_0 alkyl group, aryl group, alkyl-substituted aryl group or alkanol group); (iii) Aliphatic dicarboxylic acid compound; (iv) Succinimide; (v) Overbased magnesium or calcium A lubricating oil composition comprising a sulfonate.