JPH11323366A - Composition for lubrication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease corrosion of fine pores by making a surface of a metal substrate smooth with a lubricant composition containing at least one kind of friction improving agents. SOLUTION: A composition for lubrication is obtained by formulating 0.125-1.0 wt.% of a friction improving agent with a lubricant composition comprising 15-75 wt.% of an isobutylene sulfide, 0-25 wt.% of a phosphorous-containing anti-abrasive agent, 0-60 wt.% of a non-ash dispersing agent of a carboxyl type or a Mannich type, 0-20 wt.% of a corrosion and friction suppressing agent and 0-20 wt.% of a surface active agent and a diluting oil. The friction improving agent includes phosphonates such as an o,o- dimethylhydrocarbylphosphonate or the like, phosphites such as a dihydrocarbyl hydrogenphosphite or the like, aliphatic succimides such as a 3-(18-24C) alkenyl-2,5-pyrrolidinedione or the like, molybdenum compounds such as a molybdenum caprylate and carbonic acid amides such as an oleinic amide and one or not less than two selected therefrom are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention is directed to a friction modifier that reduces the degree of micropitting on metal surfaces, such as gear teeth.
s) and a lubricant composition containing a friction modifier.

[0002] Micropitting is a type of surface damage that occurs primarily when a hard steel surface undergoes rolling-sliding contact. This is typically the case for rolling element bearings.
bearings, most often occurring on gear teeth, and sometimes "frosting"
"Greystaining"
Or called "peeling", and when this happens, it actually creates significant problems. When micropitting occurs, noise is higher, wear rates are significantly faster, and more severe surface damage, such as scratches, can occur, and even destruction of gear teeth can occur. Conventional lubricants are used to reduce friction when the metal surfaces move in contact with each other, but they do not prevent micropitting. Original equipment manufacturers require lubricants that can reduce the degree of micropitting compared to conventional lubricants. It is an object of the present invention to satisfy such a need.

[0003] The recognition of micropitting has increased significantly within the lubricant additive industry. FZG in Germany tests micro-pitting
The Institute has established, which is called the FZG micropitting test. The test is performed on gear sets with the same metallurgy and surface contour / roughness as the gears used in the field. The conditions of this test (high load / low speed) are optimized for micropitting. Equipment manufacturers believe that the correlation between FZG micropitting tests and field experience is good.

In this FZG micropitting test, CECL
-07-A-71 Standard FZG test rig
The test is carried out using a C-type surface-hardened gear having a surface roughness of at least 0.4 Ra. The test includes a graded phase to assess micropitting accumulation and a durability phase to assess resistance to micropitting. This step-by-step step is called the load step (loa
d stage) 5 to loading stage 10 with each stage lasting 16 hours. The gear profile is measured before and during the test. Calculate the change from the original gear profile (contour deviation). The percent micropitting (percent of the gear teeth that have undergone micropitting) and the weight loss of the gear are also evaluated. After this stepwise step, the endurance step is carried out for 80 hours in load step 8 and then in load step 10 until destruction occurs. Again, the deviation from the original contour (up to 20 microns), the level of micropitting and the weight loss are measured. In particular, the result that the industry would accept would be to pass load stage 10 in the above stages of the test. This corresponds to a contour deviation after the loading stage 10 of less than 7.5 μm, a micropitting of less than 15% (about) and a weight loss of less than 15 mg (about). It is also desired to exhibit long-term performance at the endurance stage.

[0005] The present invention discloses that when a particular friction modifier is included in a lubricant composition, improved micropitting performance is observed when the lubricant composition is used, ie, the degree of micropitting is reduced. It's based on a surprising reputation that it can. Accordingly, the present invention relates to the use of at least one friction modifier for the purpose of reducing the degree of micropitting on metal surfaces, the use comprising a lubricant composition comprising at least one friction modifier. Here, the at least one friction modifier is selected, including smoothing the metal surface with an object, such that the degree of micropitting is reduced when the metal surface is so smoothed.

[0006] The metal surface may be a tooth surface of a gear, and in this case, the at least one friction modifier may be added to a gear lubricant composition containing the compounded lubricant.

[0007] In this specification, the term "friction modifier" is used to describe additive compounds commonly used in lubricant compositions to reduce friction. All friction modifiers useful in the practice of the present invention are known in the art.

In accordance with the present invention, it has been found that the technical effect of reduced micropitting desired can be obtained with the use of an optimal specific friction modifier. The effectiveness of a given friction modifier in reducing micropitting is of interest to the degree of micropitting observed when lubricating a metal surface with a lubricant composition containing the friction modifier. It can be evaluated through comparison with the degree of micropitting observed when the same metal surface is lubricated (under the same conditions) with a corresponding lubricant composition without the friction modifier. The above FZG
The micropitting test can be used to evaluate the relative performance of a lubricant composition.

Another method for identifying suitable friction modifiers is
This is a method by examining the friction coefficient of a lubricant containing the lubricant. The at least one friction modifier may comprise a lubricant having a viscosity rating of ISO 220 containing the friction modifier, which is a SAE Technical Paper.
r that can be selected to show a coefficient of friction of 0.100 or less when measured at 130 ° C. using a high frequency reciprocating rig (HFRR) under the conditions described in r 961142. I found it. Thus, the HFRR test may be used as a screen to screen for useful friction modifiers. The preparation of a lubricant composition having a viscosity rating of ISO 220 useful in screening friction modifiers involves preparing a conventional gear and sulfur containing additive package at 40 ° C. with a viscosity of 1.98 × 10 ⁻⁴ to 2.42 × 10 ⁴ . ^-4 m ² / s range of (242CSt 198) base oil (b
aseoil). Suitable additive packages include 15-75% by weight, preferably 45-65% by weight, of sulfurized isobutylene and 0-2 of a phosphorus-containing antiwear agent.
5% by weight, preferably 3-15% by weight, 0-60% by weight, preferably 5-25% by weight of ashless dispersants of the carboxyl or Mannich type, 0-20 of corrosion and friction inhibitors
% By weight, preferably 1-10% by weight, containing 0-20%, preferably 1-10% by weight of surfactant and diluent oil. Such additive packages are commercially available. This additive package is used at normal throughput rates. Base oils suitable for use in formulating such compositions include ESSO 600SN
Is 51% by weight and 2500 Brightstock is 4
Contains 9% by weight of the blend. Useful additive packages are described in EP-A-0 744 456 and EP-A-0 812 901.

A number of different types of friction modifiers have been found to be useful in the present invention. Examples include phosphonate esters, phosphite esters, aliphatic succinimides, molybdenum compounds and acid amides.

Useful phosphonate esters include O, O-
Includes di- (primary alkyl) acyclic hydrocarbyl phosphonates, wherein the primary alkyl groups are the same or different, each independently contain from 1 to 4 carbon atoms, and are bonded to a phosphorus atom. The acyclic hydrocarbyl group described above is a linear hydrocarbyl group containing 12 to 24 carbon atoms and containing no acetylenic unsaturation. Accordingly, such compounds include O, O-dimethylhydrocarbylphosphonates, O, O-diethylhydrocarbylphosphonates, O, O-dipropylhydrocarbylphosphonates, O, O-dibutylhydrocarbylphosphonates, O, O- Diisobutyl hydrocarbyl phosphonates and similar compounds with two different alkyl groups, such as O-ethyl-O-methyl hydrocarbyl phosphonates, O-butyl-O-propyl hydrocarbyl phosphonates, and O-butyl-O-isobutyl hydrocarbyl phosphonates Wherein the hydrocarbyl group is linear in each case;
It contains one or more saturated or olefinic double bonds, wherein each double bond is preferably an internal double bond. Preferred compounds are those in which both O, O-alkyl groups are the same as one another. Compounds in which the hydrocarbyl group bonded to the phosphorus atom contains 16 to 20 carbon atoms are also suitable. A preferred friction modifier of this type is dimethyl octadecyl phosphonate. Phosphonate esters useful in the present invention are disclosed in U.S. Pat.
No. 8,633.

Useful phosphite esters are described in WO 88
/ 04313. They include dihydrocarbyl hydrogen phosphites and amine salts of the phosphites, wherein the hydrocarbyl group is
The same or different, each is a linear aliphatic hydrocarbyl group independently containing 8 to 24 carbon atoms and containing no acetylenic unsaturation. Such phosphites typically have 12 to 24 carbon atoms each,
Preferably it contains 16 to 20 linear aliphatic hydrocarbyl groups. It is also preferred that at least 50% of the hydrocarbyl groups of the dihydrocarbyl hydrogen phosphite contain at least one internal double bond. The use of dioleyl phosphite is preferred.

Suitable amine salts of the above-mentioned dihydrocarbyl hydrogen phosphites are those wherein the aliphatic group of the amine is a linear primary aliphatic group having from 8 to 24 carbon atoms, for example from 16 to 20 carbon atoms. At least 50 of the aliphatic groups
% Contains one or more internal double bonds.

Useful succinimides include those of the formula:

[0015]

Embedded image Wherein Z is a group R ¹ R ² CH—, wherein R ¹ and R ² are the same or different and are each independently a straight or branched chain carbon containing 1 to 34 carbon atoms. Which represents a hydrogen group and the total number of carbon atoms in the groups R ¹ and R ² is from 11 to 35]. The compound is described in European Patent Application Publication No. 0020.
No. 037, EP-A-0 389 237 and EP-A-0 776 964.

The group Z may be, for example, 1-methylpentadecyl, 1-propyltridecenyl, 1-pentyltridecenyl, 1-tridecylpentadecenyl or 1-tetradecyleicosenyl. Good. The number of carbon atoms in said groups R ¹ and R ² is preferably from 16 to 28,
More typically it is 18 to 24. It is particularly preferred that the total number of carbon atoms in R ¹ and R ² is about 20 or about 22. The succinimide is preferably a 3-C _18-24 alkenyl-2,5-pyrrolidinedione. One example of such a succinimide contains a mixture of alkenyl groups having 18 to 24 carbon atoms.

Useful molybdenum compounds are disclosed in US Pat.
650,381. Such compounds are typically substantially free of active sulfur. Examples of suitable compounds include glycol molybdate complexes as described in U.S. Pat. No. 3,285,942, molybdenum-containing overbased alkali metals as disclosed in U.S. Pat. No. 4,832,857, and Alkaline earth metal sulfonate, phenates and salicylate compositions, molybdenum complexes made by reacting a diethanolamine with a molybdenum source with a fatty oil as described in US Pat. No. 4,889,647; Patent No. 5,137,
Molybdenum-containing compounds made from fatty acids and 2- (2-aminoethyl) aminoethanol as described in US Pat. No. 647, amines, diamines and alkoxyls as described in US Pat. No. 5,143,633. Overbased molybdenum complexes made from fluorinated amines, glycols and polyols, and US Pat. No. 5,412,130
2,4-heteroatom-substituted molybdena-3,3-dioxacycloalkanes as described in US Pat.

Molybdenum salts, such as carboxylate salts, are a preferred group of molybdenum compounds. The molybdenum salt used in the present invention may be in a completely dehydrated state (water may be completely removed during preparation) or may be in a partially dehydrated state. They may be salts or mixed salts made from the same anion, meaning that they are made from more than one acid. Examples of those suitable anions include chloride, carboxylate, nitrate, sulfonate or any other anion.

The molybdenum carboxylate is preferably a monocarboxylic acid, for example a salt of a monocarboxylic acid having about 4 to 30 carbon atoms. Such an acid may be a hydrocarbon aliphatic, cycloaliphatic or aromatic carboxylic acid.
Monocarboxylic fatty acid acids having about 4 to 18 carbon atoms are preferred, and fatty acids having an alkyl group having about 6 to 18 carbon atoms are particularly preferred. Cycloaliphatic acids may generally contain from 4 to 12 carbon atoms. Aromatic acids generally contain one or two fused rings and from 7 to 14 carbon atoms, and the carboxyl group may or may not be directly attached to the ring. The carboxylic acid may be a saturated or unsaturated fatty acid having about 4 to 18 carbon atoms. Examples of carboxylic acids that can be used in the preparation of molybdenum carboxylate include butyric acid, valeric acid, caproic acid,
Heptanoic acid, cyclohexanecarboxylic acid, cyclodecanoic acid, naphthenic acid, phenylacetic acid, 2-methylcaproic acid, 2-ethylcaproic acid, suberic acid, caprylic acid,
Nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, linolenic acid, heptadecanoic acid, stearic acid, oleic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid, docosanoic acid and erucic acid Is included. A preferred molybdenum carboxylate is molybdenum caprylate.

Useful carboxylic acid amides include aliphatic monocarboxylic acid amides. These are of the formula (R ³ C
O) N (R ⁴ ) (R ⁵ ) wherein R ³ has 8 carbon atoms
To 24 alkyl or alkenyl groups, and R ⁴ and R ⁵ may be the same or different;
Each independently is hydrogen or alkyl having 7 or less carbon atoms]. R ³ is typically C
Represents a _14-18 alkyl group. Amides of this type are described in U.S. Pat. No. 4,280,916. A preferred friction modifier of this class is oleamide.

Friction modifiers useful in the present invention are commercially available or can be prepared by employing or applying known methods.

The amount of the at least one kind of friction modifier used is at least an amount sufficient for it to perform its intended micropitting reducing function. Such friction modifier (s) are generally used at normal processing rates. The total concentration of the friction modifier used is typically from 0.125 to 1% by weight, based on the total weight of the lubricant composition. The total amount of the friction modifier is preferably between 0.15 and 0.75% by weight, more preferably about 0.5% by weight.

Mixtures of friction modifiers can also be used. In this case, the same or different kinds of friction modifiers may be used in combination. For example, satisfactory results have been obtained when dimethyloctadecylphosphonate and 3- _{C18-24alkenyl-} 2,5-pyrrolidinedione are used in combination. The total amount of friction modifier when a mixture of friction modifiers is used is also as described above.

It is important that the at least one friction modifier used is sufficiently soluble in the lubricant composition at the treat rate at which it is used. It is also important that the at least one friction modifier be sufficiently compatible with the additional components normally present in lubricating compositions. Such components include dispersants, detergents, antioxidants, extreme pressure agents (extremep).
stress agents), anti-wear agents, defoamers,
Includes viscosity index improvers and pour point depressants. Such additives are used in their own usual amount.

The base oil used in formulating the lubricant composition useful in the present invention may be a natural or synthetic oil or a blend thereof. Useful base oils are known in the art. The compounding of the lubricant composition takes place in the usual manner by blending the individual components. The time at which the at least one friction modifier capable of improving the micropitting performance is added may be the time when the lubricant is being compounded. Alternatively, the at least one friction modifier can be added as a top treat to enhance or enhance the micropitting performance of existing lubricant compositions incorporating the same.

The present invention also provides a lubricant composition exhibiting excellent micropitting performance as compared with ordinary lubricants. 1
In one embodiment, the present invention provides a lubricant composition comprising an O, O-di- (primary alkyl) acyclic hydrocarbyl phosphonate as described above and a succinimide as described above. The composition preferably includes dimethyloctadecylphosphonate and 3- _{C18-24alkenyl-} 2-pyrrolidinedione. In another embodiment, the composition comprises a molybdenum carboxylate, such as molybdenum caprylate, and a sulfurized isobutylene extreme pressure agent. Such compositions can also include one or more other additive components described above.

The following examples illustrate the invention.

[0028]

Examples 1-7 A lubricant composition was prepared by blending the components listed in Table 1 below. The gear additive package containing sulfur and phosphorus had the following composition: 50% by weight Sulfurized isobutylene (extreme pressure agent) 8% by weight Mixed phosphite and phosphonate antiwear agent 17.5% by weight Boron phosphorylated of succinimide dispersant 9 wt% rust inhibitor package 2.6 wt% corrosion inhibitor 0.5 wt% defoamer 0.15% demulsifier 1.5 wt% 3-C _18-24 alkenyl-2,5 Pyrrolidinedione Remaining base (dilution) oil This base oil was ESSO ISO 220. The viscosity rating of each composition was ISO 220.

[0029]

[Table 1] The coefficient of friction of each composition was determined using HFRR and SAE Te.
130 operating under the conditions described in Chinese Paper 961142 (ball diameter 6 mm, load 4 N, frequency 20 Hz, stroke length 1 mm; ball and flat ANSI 52100 steel).
Measured in ° C. Table 2 shows the HFRR coefficient of friction of each composition. Each composition was also subjected to a FZG micropitting test according to CEC L-07-A-71. Table 2 also shows the results obtained in this test.

The solubility / compatibility of the friction modifier (s) in the lubricant composition was tested by visually evaluating the appearance of the composition. The presence of a precipitate indicates poor solubility / compatibility. Table 2 reports the degree of solubility / compatibility.

After the loading stage 10, the percent micropitting and weight loss were evaluated. Weight loss was measured by comparing the initial weight of the gear under test to the weight of the gear after load stage 10. Table 2 also shows the results.

[0032]

[Table 2] The above table shows the FZG results as load stage results (at the staged stage). A 7.5 μm contour deviation is used to distinguish between a pass or fail result at a given load stage. For example, experiments 1 and 2 are "10 failed"
And "9 Fail" results, which indicate that the profile deviation exceeded 7.5 μm, respectively, at load stage 10.
After (experiment 1) and after loading stage 9 (experiment 2). On the other hand, in Experiment 4-7, FZG of “10 passed”
The result gives, which means that the contour deviation did not exceed 7.5 μm after the loading stage 10.

The results in Table 2 show that the friction coefficient obtained in the HFRR test can be used to predict which friction modifier (s) will be useful for improving micropitting performance. . An HFRR result of less than 0.100 helps predict friction modifiers that provide improved micropitting performance.

The lubricant compositions used in Experiments 1 and 2 are conventional gear lubricants. This provided adequate micropitting protection, and the threshold of 7.5 μm was exceeded after loading stage 10 (Experiment 1) or after loading stage 9 (Experiment 2). In Experiment 3, the micropitting test failed after loading stage 6 as it was confirmed that the tested composition contained a precipitate. This underscores the fact that the friction modifiers used need to be completely soluble / compatible with the lubricant at the treat rates at which they are used. The compositions used in Experiments 4-7 are examples of the present invention, which are the improved FZG results compared to the normal lubricant compositions of Experiments 1 and 2, "10
Passed ". A consistent "10 pass" result is a very satisfactory result in the industry. Also, the percent level of micropitting and weight loss exhibited by Experiments 4-7 were satisfactory.

EXAMPLE 8 For the purpose of verifying the accuracy of the procedure for screening friction modifiers, glycerol monooleate, a friction modifier known to exhibit inferior micropitting protection, was viscosified. The resulting composition was included in a lubricant composition of grade ISO 220 and the resulting composition was tested in the HFRR test (SAE Technical Paper 9611).
42). This composition gave an HFRR result of 0.114, well above the threshold of 0.100.

Examples 9 and 10 The above HFRR screening procedure was repeated with compositions using various gear additive packages containing sulfur and phosphorus. The base oil is ESSO I
SO 220. The viscosity rating of the formulated composition is I
SO 220. The treatment rates of the various components and the HFRR results obtained are shown in Table 3 below.

[0037]

[Table 3] The fact that the HFRR result of Experiment 9 exceeded 0.100 is consistent with the HFRR results of Experiments 1 and 2 shown in Table 1. The combination of friction modifiers included in the composition used in Experiment 10 was a combination of friction modifiers confirmed to provide improved micropitting performance (Experiment 6 shown in Table 2).
See results). The HFRR result of experiment 10 was 0.
It is less than 100. This is the same as in Experiment 6 shown in Table 2.
(Using different gear additive packages when formulating the composition under test). This shows that the HFRR screening procedure helps predict useful friction modifiers even when using different gear additive packages in the lubricant composition formulation.

The features and embodiments of the present invention are as follows.

1. Use of at least one friction modifier to reduce the degree of micropitting on the metal surface, comprising lubricating the metal surface with a lubricant composition comprising at least one friction modifier. Wherein the at least one friction modifier is selected such that the degree of micropitting is reduced when the metal surface is so smoothed.

2. The use according to claim 1, wherein said lubricant composition is a gear lubricant composition.

3. Said at least one friction modifier,
ISO 2 containing the at least one friction modifier
A lubricant exhibiting a viscosity grade of 20 was obtained from SAE Technic
1 using a high frequency reciprocating rig (HFRR) under the conditions described in alPaper 961142.
3. Use according to paragraphs 1 or 2, wherein it is selected such that it exhibits a coefficient of friction of 0.100 or less when measured at 30 ° C.

4. The friction modifier is an O, O-di- (primary alkyl) acyclic hydrocarbyl phosphonate;
Wherein the primary alkyl group is the same or different and each independently contains 1 to 4 carbon atoms and the acyclic hydrocarbyl group bonded to the phosphorus atom contains 12 to 24 carbon atoms and is an acetylenic group. 4. Any one of the above items 1 to 3, which is a linear hydrocarbyl group containing no unsaturation.
Use as described in section.

5. The use according to claim 4, wherein said friction modifier is dimethyl octadecyl phosphonate.

6. The friction modifier is dihydrocarbyl hydrogen phosphite or an amine salt thereof, wherein:
The first hydrocarbyl group is the same or different and each is independently a linear aliphatic hydrocarbyl group containing 8 to 24 carbon atoms and containing no acetylenic unsaturation;
Use according to any one of claims 1 to 3.

7. 7. The use according to claim 6, wherein said friction modifier is dioleyl phosphite.

8. The friction modifier has the formula:

[0047]

Embedded image Wherein Z is a group R ¹ R ² CH—, wherein R ¹ and R ² are the same or different and are each independently a straight or branched chain carbon containing 1 to 34 carbon atoms. Represents a hydrogen group and the total number of carbon atoms in said groups R ¹ and R ² is 1
Succinimide represented by the formula:
Use according to any one of claims 1 to 3.

9. The use according to claim 8, wherein said friction modifier is 3- _{C18-24alkenyl-} 2,5-pyrrolidinedione.

10. Use according to any of claims 1 to 3, wherein said friction modifier is a molybdenum compound.

11. The use according to claim 10, wherein said friction modifier is molybdenum carboxylate.

12. The use according to claim 11, wherein said friction modifier is molybdenum caprylate.

13. The friction modifier has the formula (R ³ CO) N
(R ⁴ ) (R ⁵ ) [wherein R ³ has 8 to 2 carbon atoms.
It represents 4 alkyl or alkenyl group and R ⁴
And R ⁵ may be the same or different and are each independently hydrogen or alkyl having 7 or less carbon atoms]. Use according to any one of the preceding claims.

14. 14. Use according to claim 13, wherein said friction modifier is oleamide.

15. 15. Use according to any one of the preceding claims, wherein the at least one friction modifier is used in an amount of 0.125 to 1.0% by weight, based on the total weight of the lubricant composition.

16. A lubricant composition comprising the O, O-di- (primary alkyl) acyclic hydrocarbylphosphonate of claim 4 and the succinimide of claim 8.

17. _17. The lubricant composition according to claim 16, comprising dimethyloctadecylphosphonate and 3- _{C18-24alkenyl-} 2-pyrrolidinedione.

18. A lubricant composition comprising molybdenum carboxylate and an isobutylene sulfide extreme pressure agent.

19. Use according to claim 1 substantially as described above in this specification.

20. 16. The lubricant composition according to clause 15, substantially as described above herein.

21. 18. The lubricant composition according to clause 17, substantially as described hereinabove.

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[Procedure amendment]

[Submission date] May 17, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10M 133: 16) (C10M 141/12 137: 12 133: 44 133: 16 139: 00 135: 04) C10N 10:12 30: 06 30:12 40:04 (72) Rodney I. Barber, Inventor, Berkshire, Aalzie, United Kingdom 97 Dove Youth Bracknell Greenham Woods 98 (72) Inventor, Craig Earl Patterson, Berkshire, Newbury, Sutachiam, United Kingdom Tref Oil Drobe 18

Claims (3)

[Claims] 1. Use of at least one friction modifier to reduce the degree of micropitting on a metal surface, said metal surface being lubricated with a lubricant composition comprising at least one friction modifier. Wherein the at least one friction modifier is selected such that the degree of micropitting is reduced when the metal surface is so smoothed. 2. A lubricant composition, comprising O, O-di-
A lubricant composition comprising a (primary alkyl) acyclic hydrocarbyl phosphonate and succinimide. 3. A lubricant composition comprising molybdenum carboxylate and a sulfurized isobutylene extreme pressure agent.