JP2936071B2 - Borated and non-borated overbased carboxylate salts as corrosion inhibitors - Google Patents

Abstract

A corrosion inhibitor additive for gear oil formulations is disclosed in the form of an overbased carboxylate which can be in a borated or non-borated form. Borated versions of the overbased carboxylate are preferred and are obtained by reacting a boron reactant such as boric acid with an overbased carboxylate. The overbased carboxylate in its borated and non-borated forms has been found to be effective in improving the corrosion inhibiting properties of gear oil formulations which are used under severe operating conditions wherein the gear oil might come into contact with contaminant water. A method of improving the corrosion resistance of a gear oil having contaminant water therein is also disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION Cross Reference This application is a subject related in part to the disclosure of pending US Application No. 047,754, filed May 7, 1987, the inventor of which is I. Claim. The disclosure of previously filed application No. 047,754 is incorporated herein by reference. The priority of the earlier application is claimed to the extent possible under 35 USC 120.

FIELD OF THE INVENTION The present invention relates generally to the field of additives contained in lubricant compositions to improve the performance characteristics of lubricants. More specifically, the present invention relates to additive compounds that act as corrosion inhibitors in gear oil compositions.
The corrosion inhibitor has a borated and non-borated form of the overbased carboxylate.

BACKGROUND OF THE INVENTION The ability to prevent corrosion, rust formation, oxidation and degradation
A very important property of lubricating compositions and functional fluids.
The importance of such properties is becoming increasingly important when the lubricant or functional fluid is used in severe operating conditions in conjunction with very expensive equipment. The importance of corrosion protection capability is further accentuated when the lubricant (eg, gear oil) is used in environments that come into contact with water under extreme temperature and pressure conditions.
In the absence of corrosion inhibitors with high performance characteristics, the useful life of the machine is significantly reduced. Therefore, many device manufacturers that require the use of functional fluids and lubricants require that such fluids and lubricants contain a corrosion inhibitor. Numerous tests have been devised to evaluate the corrosion protection properties of lubricants and functional fluids when used under harsh conditions. Accordingly, there is a strong need for corrosion inhibitors that are easily and economically manufactured and that can be added to provide corrosion protection properties to lubricants and functional fluids.

U.S. Pat. No. 3,929,650 to King et al. Discloses a particulate dispersion of an alkali metal borate. The borate is prepared by contacting boric acid with an alkali metal carbonate overbased metal sulfonate in a lipophilic liquid reaction medium. The reactants are contacted at a temperature in the range of 20-200 ° C for 0.5-7 hours. The molar ratio of boric acid to alkali metal carbonate is in the range of 1-3.

U.S. Pat. No. 3,595,790 to Norman et al.
Many different oil-soluble and overbased metal salts of various organic acids are disclosed. Sulfonates, carboxylates and phosphates can be combined with such acids in substantially anhydrous conditions in the presence of an acid gas (eg, carbon dioxide) and a promoter (eg, an alcohol). It is obtained by reacting with an amount of a metal base. This basic metal salt neutralizes the undesired acidic substances formed in the crankcase oil (which is a lower viscosity oil than the gear oil) during operation of the engine. It has been shown to be useful as an additive in oils.

SUMMARY OF THE INVENTION The present invention is a corrosion inhibitor additive compound for use with a lubricant in the form of a gear oil. The corrosion inhibitor is preferably in the form of a borated overbased carboxylate. The borated versions of the overbased carboxylate additives of the present invention are most commonly prepared by reacting a boron reactant (preferably boric acid) with an overbased carboxylate. Is done.
The invention also relates to a method for improving the corrosion protection properties of gear oils. This process involves the use of borated and / or non-borated variants of the corrosion inhibitor of the present invention in small amounts (0.1% by weight of gear oil).
(% To 5% by weight) to gear oils containing impure water and dispersing the corrosion inhibitor in the system to improve the overall corrosion protection properties.

It is an object of the present invention to provide a corrosion inhibitor useful in a wide range of lubricating and functional fluid compositions, especially gear oils.

An advantage of the present invention is that the overbased carboxylate compositions of the present invention are easily and economically manufactured to prevent corrosion, rust formation, oxidation and degradation, and are lubricated in the form of gear oils. It can be included in a composition.

A feature of the present invention is that the corrosion inhibitor additive can be provided in the form of various overbased carboxylate salts. More specifically, the acid anion portion of the carboxylate, like the metal cation portion of the molecule, is readily available and is as economical as any borating agent.

Another advantage of this corrosion protection composition is that it can impart corrosion resistance to gear oils without acting to antagonize protection against nicks and impact loads at high speeds. This antagonistic property is generally obtained by the use of free carboxylic acids, which are another well-known class of corrosion inhibitors.

Yet another advantage of the present invention is that the corrosion inhibitor is
It is to provide gear oils with improved properties without undesired effects on the oxidative and / or thermal stability of the gear oils. Such undesirable effects are brought about when utilizing amine compounds as corrosion inhibitors.

These and other objects, advantages and features of the present invention will become apparent to those of skill in the art upon a detailed reading of the formulations, synthetic methods and uses described in more detail below.
Reference is made to the attached general structures which form part of them. Here, the same symbols consistently represent the same molecular moiety.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the corrosion inhibitor additives of the present invention, the process of making such additives, oil formulations, methods of improving corrosion, and additive concentrates, the present invention requires that Compound, process,
Without being limited to formulations, methods or concentrates, the compounds, processes, formulations, methods and concentrates as described are
Of course, it should be understood that it can be varied. It is also to be understood that the terminology used herein is for describing particular embodiments only and is not intended to be limiting. This is because the scope of the present invention is limited only by the appended claims.

As used in this specification and the appended claims, the singular forms "a,""an," and "the" refer to plural referents unless the context clearly dictates otherwise. Include. Thus, for example, an indication for "an overbased carboxylate" includes a mixture of such carboxylate salts,
References to "an corrosion inhibitor" include mixtures of such corrosion inhibitors, and references to "oils" include mixtures of such oils and the like.

The present invention provides corrosion inhibitor additives that can be used with lubricants and functional fluids. This additive is in the form of an overbased carboxylate. The carboxylate may be in a borated or non-borated form. This borated version is generally indicated to be preferred. This variant is
It is prepared by reacting a boron reactant (preferably boric acid) with an overbased carboxylate. Overbased carboxylate is used in crankcase engine oil (which is a lower viscosity oil than gear oil) to neutralize acidic components formed during engine operation It has been known.
These acidic components are formed by the "engine blowback phenomenon". This phenomenon does not occur with rear axle assemblies.

In the context of the present disclosure, the term "overbased"
Or "overbased compound" or "overbased carboxylate" is generally used to refer to a metal salt in which the metal ion is present in a stoichiometrically greater amount than the organic acid group. . Methods commonly used to prepare overbased compounds include acids (e.g.,
Carboxylic acid) with a stoichiometric excess of a metal neutralizing agent (eg, a metal oxide, hydroxide, carbonate, bicarbonate or sulfide) at a temperature above 50 ° C. ,
And filtering the resulting mass.

In connection with the production of overbased compounds, it is generally preferred to use an accelerator in the neutralization step to assist in mixing a large excess of metal. Particularly effective methods of preparing overbased carboxylate salts include carboxylic acids and
Mixing a stoichiometric excess of a basic alkaline earth neutralizer (e.g., calcium hydroxide) and at least one alcohol promoter, and adding the mixture to an elevated temperature (from 10C to 200C). ° C. which may be in the range of, but more preferably at present) in the range of about 40 ° C. to 80 ° C., by passing the CO _2, the carbonating the mixture are included.

The inventor has recognized that the corrosion inhibiting properties of various lubricating compositions and functional fluids (particularly gear oil formulations) can be improved by including additives, preferably in the form of borated overbased carboxylate salts. It has been found that it can be greatly improved. Such overbased carboxylate salts react a stoichiometric excess of a metal neutralizing agent with a statistical mixture of carboxylic acids to form a stoichiometric excess of a metal-containing carboxylic acid. Prepared by forming a statistical mixture of acid salts. The anionic portion of the corrosion inhibitor of the present invention is an ionized carboxylic acid or an ionized carboxylate, and most preferably a statistical mixture thereof. A statistical mixture of components is a mixture of numerous components that differ slightly from one another over a wide range (eg, differ in molecular weight and shape). The cationic portion of the corrosion inhibitor of the present invention is typically an alkali metal ion or an alkaline earth metal ion. Certain specific metals that may be utilized include lithium, potassium, sodium, magnesium, calcium and barium, with sodium, calcium and magnesium being preferred.

In preparing the present invention, a large number of different types of carboxylic acids can be used individually or preferably in a statistical mixture. Useful carboxylic acids include oleic, tall oil, palmitic, linoleic, stearic and lauric acids. Other carboxylic acids that are oil-soluble or dispersible when combined in a salt form with other additives in a lubricant that is a functional fluid may also be used in connection with the present invention. Useful carboxylic acids are generally 12
Has from 22 to 22 carbon atoms.

The carboxylic acid component is converted to a salt by reacting it with a metal neutralizer. The neutralizing agent may be the metal itself, an oxide, hydroxide, carbonate, bicarbonate or sulfide of the metal. Such neutralizing agents can be used individually or preferably in combination with one another in a statistical mixture. Metals and metal compounds of sodium, calcium and magnesium are preferably used in the context of the present invention. However, other alkali and alkaline earth metals and their compounds can be used for the production of the overbased carboxylate of the present invention.

The overbased carboxylate of the present invention comprises reacting one or more carboxylic acids, or a statistical mixture thereof shown above, with one or more neutralizing agents shown above. Can be obtained by The neutralizing agent may be added in a stoichiometric excess of the organic acid. Means of conducting the reaction between the organic acid and the neutralizing agent are set forth above. A typical reaction involves the reaction of calcium hydroxide with oleic acid to form a calcium carboxylate (more specifically, calcium oleate).

Such a reaction product may be represented by the following general empirical formula (I): Ca (RCOO) ₂ .XCa (OH) ₂ .YCaCO ₃ where R is hydrocarbyl and combined X and Y are greater than one and vary depending on the degree of overbasing desired.

Different ranges of "R _2" is present in a preferred statistical mixture of the present invention.

In Formula (I), and elsewhere in this disclosure, hydrocarbyl means "hydrocarbon-based." As used herein, the term "hydrocarbon-based",
"Hydrocarbon-based substituents" and the like, within the context of the present invention, denote substituents having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character.

Examples of hydrocarbyl substituents useful in connection with the present invention include: (1) hydrocarbon substituents, ie, aliphatic substituents (eg, alkyl or alkenyl), alicyclic substituents ( For example, cycloalkyl, cycloalkenyl), aromatic, aliphatic and alicyclic-substituted aromatics, and the like,
Cyclic substituent. Wherein the ring is completed by another part of the molecule (ie, for example, any two indicated substituents may together form an alicyclic group); 2) Substituted hydrocarbon substituents, ie, these substituents have non-hydrocarbon groups. The non-hydrocarbon groups do not, in the context of the present invention, primarily alter the hydrocarbon substituents; such groups as, for example, halo (especially chloro and fluoro), alkoxy, mercapto, alkylmercapto, nitro, nitroso, Sulfoxy)
Are known to those skilled in the art; (3) heterosubstituents, ie, within the context of the present invention,
It has substituents other than carbon present in the ring or chain while having mainly hydrocarbon properties, but the others are substituents composed of carbon atoms. Suitable heteroatoms will be apparent to those of skill in the art and include, for example, sulfur, oxygen, nitrogen. For example, substituents such as pyridyl, furanyl, thiophenyl, imidazolyl, and the like are examples of these hereto substituent heteroatoms. Preferably, there is only one heteroatom for each 10 carbon atoms of the hydrocarbon-based substituent. Typically, such groups or heteroatoms are not present in the hydrocarbon-based substituent. Thus, it is a pure hydrocarbon.

Certain preferred carboxylic acids used in preparing the overbased carboxylic acid salts include tall oil fatty acids, oleic acid, linoleic acid, and palmitic acid. Certain preferred neutralizing agents include sodium hydroxide, calcium hydroxide and magnesium hydroxide. Statistical mixtures of overbased calcium carboxylate are considered particularly preferred.

After this overbased carboxylate is formed,
The carboxylate can be borated by reacting with a boron reactant. The boron reactant is preferably in the form of boric acid. To perform this reaction, boric acid is charged to the reaction medium containing the overbased carboxylate in the amount required to form the preferred type of borate. Different amounts of H ₃ BO ₃ can be loaded into the system to obtain the desired amount of borate incorporation. This depends on the end result desired and on the particular functional fluid or lubricating composition (in which connection, rust inhibitors may be used).

Useful boron reactants include boric acid, and various alkyl borates (eg, tributyl borate) and sodium metaborate, with boric acid being more preferred. The overbased carboxylate can be fully or partially borated with one or more boron reactants.

The overbased carboxylate rust inhibitor in the borated or non-borated variant may be used in an amount sufficient to improve the rust inhibiting performance of the lubricant or fluid. It can be in a composition or a functional fluid (eg, gear oil). This amount can be determined by one skilled in the art and will vary depending on factors such as: oil-based type, end use, and other additives present in the formulation. There is. Generally, this rust inhibitor will be present at about 0.1% by weight, based on the weight of the fully formulated lubricant or functional fluid.
It is present in an amount within the range of 3% by weight (preferably about 0.2% to about 1.5%, most preferably about 0.5% by weight).

Carboxylic acids from which overbased salts suitable for use in the present invention can be prepared include aliphatic, cycloaliphatic, and aromatic monobasic and polybasic carboxylic acids. These include, for example, naphthenic acids, alkyl- or alkenyl-substituted cyclopentanoic acids, alkyl- or alkenyl-substituted cyclohexanoic acids, alkyl- or alkenyl-substituted aromatic carboxylic acids. The aliphatic acid generally has at least 8 carbon atoms, preferably at least 12 carbon atoms. Typically, they have no more than about 400 carbon atoms.
In general, when the aliphatic carbon chain is branched, the acid becomes more oil soluble for any carbon atom content. The cycloaliphatic carboxylic acids and aliphatic carboxylic acids can be saturated or unsaturated. Specific examples include 2-
Ethylhexanoic acid, α-linolenic acid, propylene tetramer-substituted maleic acid, behenic acid, isostearic acid, pelargonic acid, capric acid, palmitoleic acid, linoleic acid, lauric acid, oleic acid, ritinoleic acid, undecylic acid, dioctylcyclopentanecarboxylic acid , Myristic acid, dilauryldecahydronaphthalenecarboxylic acid, stearyl-octahydroindenecarboxylic acid, palmitic acid, commercially available mixtures of two or more carboxylic acids (eg, tall oil acids, rosin acids), and the like. It is preferred to use a statistical mixture of such acids having from 12 to 400 carbon atoms.

A typical group of oil-soluble carboxylic acids useful in preparing the salts used in the present invention are oil-soluble aromatic carboxylic acids. These acids are represented by the following general formula: Here, R ^* is an aliphatic hydrocarbon-based group having at least 4 carbon atoms and no more than 400 aliphatic carbon atoms. a is an integer of 1 to 4, Ar ^* is 14
A polyvalent aromatic hydrocarbon nucleus having up to carbon atoms, each X
^* Is independently a sulfur or oxygen atom, and m
Is an integer from 1 to 4, provided that (R ^* ) _a is a group of formula IV
Has at least 8 aliphatic carbon atoms for each acid molecule represented by Examples of aromatic nuclei represented by various Ar ^* include polyvalent aromatic groups derived from: benzene, naphthalene, anthracene, phenanthrene, indene, fluorene, biphenyl and the like.
Generally, the group represented by Ar ^* is a multivalent nucleus derived from benzene or naphthalene (eg, phenylene and naphthalene). The nucleus includes, for example, methylphenylene, ethoxyphenylene, nitrophenylene, isopropylene, hydroxyphenylene, mercaptophenylene, N, N-diethylaminophenylene, chlorophenylene, N, N-diethylaminophenylene, chlorophenylene, dipropoxynaphthylene, Triethylnaphthylene and their similar trivalent, tetravalent, pentavalent nuclei and the like.

The R ^* group is usually a hydrocarbyl group, preferably a group such as an alkyl or alkenyl group.
However, the R ^* group may have a small number of substituents such as: phenyl, cycloalkyl (eg, cyclohexyl, cyclopentyl, etc.), and non-hydrocarbon groups (eg, nitro, amino, halo (eg, Chloro, bromo, etc.), lower alkoxy, lower alkyl mercapto, oxo substituent (ie, = 0), thio group (ie, ＳS), interrupting group (eg, —NH—, —O—, —
S-). However, the substantial hydrocarbon nature of the R ^* group is retained. The hydrocarbon character is non-carbon atoms of any present in R ^* group, unless more than about 10% of the total weight of the R ^* group is retained for purposes of the present invention.

Examples of R ^* groups include butyl, isobutyl, pentyl, octyl, nonyl, dodecyl, docosyl, tetracontyl, 5-chlorohexyl, 4-ethoxypentyl, 4-
Hexenyl, 3-cyclohexyloctyl, 4- (p-
Chlorophenyl) -octyl, 2,3,5-trimethylheptyl, 4-ethyl-5-methyloctyl, and substituents derived from polymerized olefins such as: polychloroprene, polyethylene, polypropylene, Polyisobutylene, ethylene-propylene copolymer, chlorinated olefin polymer, oxidized ethylene-propylene copolymer, and the like. Similarly, an Ar ^* group may contain, for example, non-hydrocarbon substituents (eg, various substituents such as: lower alkoxy, lower alkyl mercapto, nitro, halo, less than 4 carbon atoms) An alkyl or alkenyl group having, hydroxy,
Mercapto and the like.

The carboxylic acids corresponding to Formulas IV-V above are well known or can be prepared according to methods well known in the art. Methods of preparing carboxylic acids of the type illustrated in the above formula, and their overbased metal salts, are well known and disclosed, for example, in the following U.S. Patents: U.S. Patent Nos. 2,197,832; 2,197,835; No. 2,252,662
No. 2,252,664; 2,714,092; 3,410,798 and 3,595,791. The disclosure of these acids and the method of preparing the overbased salts are incorporated herein by reference.

The following examples are set forth in order to provide those skilled in the art with a complete disclosure and description of how to make the overbased carboxylate salts of the present invention, and lubricant formulations (gear oils). I have. Therefore, these examples do not limit the range that the present inventors regard as the invention. Efforts have been made to ensure accuracy with respect to numbers and terms used (eg, amounts, compounds, temperatures, etc.), but some experimental error and deviation should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in degrees Celsius, and pressure is at or near atmospheric.

Example A alkylated salicylic acid (the alkyl group is, on average, about
About 512 parts by weight of a mineral oil solution containing about 0.5 equivalents of a substantially neutral magnesium salt (having 18 aliphatic carbon atoms) and about 250 parts by weight of xylene are added to the flask. About 60
Heat to a temperature between ° C and 70 ° C. Increase heating to about 85 ° C and add approximately 60 parts by weight of water. The reaction is held at a reflux temperature of about 95 ° C to 100 ° C for about 1-1 / 2 hours, followed by removal of volatile components under vacuum at a temperature of 155 ° C to 160 ° C, And filter. The filtrate contains a basic magnesium carboxylate containing 200% of a stoichiometrically equivalent amount of magnesium.

Example B Alkylated salicylic acid (the alkyl group is, on average, about
About 506 parts by weight of a mineral oil solution containing about 0.5 equivalents of a substantially neutral magnesium salt (having 16 to 24 aliphatic carbon atoms) is added to about 22 parts by weight of magnesium oxide (about 1.0 equivalent) and about Fill the reaction flask with 250 parts by weight. Heat the temperature to about 60-70 ° C. Increase heating to about 85 ° C., add approximately 60 parts by weight of water to the reaction, and heat to reflux. The reaction is held at a reflux temperature of about 95 ° C. to 100 ° C. for about 1-1 / 2 hours, followed by removal of volatile components at 40 torr at a temperature of about 155 ° C. and filtration . The filtrate contains a basic magnesium carboxylate containing stoichiometrically equivalent 274% of magnesium.

Example C An alkylated salicylic acid (where the alkyl group is 1616) is prepared by reacting magnesium chloride with a substantially neutral potassium salt of the alkylated salicylic acid in approximately stoichiometric amounts.
Substantially neutral magnesium salt (having 2 to 24 aliphatic carbon atoms). Mineral oil solution (this is approximately 6.% of the substantially neutral magnesium salt of the alkylated salicylic acid).
A reactant containing approximately 6580 parts by weight (containing 50 equivalents) and about 388 parts by weight of an oil mixture (which contains about 0.48 equivalents of alkylated benzene sulfonic acid) is added to about 285 parts by weight of magnesium oxide (14 equivalents). And the flask with approximately 3252 parts by weight of xylene. From about 55 ℃
Heat to a temperature of 75 ° C. Raise the temperature to about 82 ° C, about 78
0 parts by weight of water are added to the reaction and then heated to reflux temperature. The reaction is maintained at a reflux temperature of about 95-100 ° C. for about 1 hour, followed by under 50 torr,
At a temperature of about 170 ° C., the volatile components are removed and filtered.
The filtrate contained a basic magnesium carboxylate and 15.7% (this is 276% of the stoichiometric equivalent).
Sulphated ash content (sulphated ash).

Examples A-1, B-1, C-1 Individual overbased carboxylate salts for any of Examples AC, or a mixture of carboxylate salts from all or any of AC, Reaction with a suitable borating agent (e.g., boric acid) can be borated, preferably borated, to give Examples A-1, B-1 and C-1, respectively. The resulting borated carboxylate provides improved rust protection in lubricants (eg, gear oils).

Example 1 Gear oil (especially SAE80W-90 (80% 600N + 20% 150
A gear oil formulation is prepared by initiating the reaction with the base oil formulation utilized in making Bright Stock)). To this base oil composition is added 0.25% by weight of a borated overbased carboxylate obtained by reacting the overbased carboxylate of Example A with boric acid. Thereafter, a suitable pour point depressant, especially the reaction product of a maleic anhydride / styrene copolymer with an alcohol and an amine, is added. This pour point depressant is added in an amount of 1% by weight. 1% of a phosphate ester neutralized with an amine and 0.075% by weight of an oleamide / linoleamide mixture of hydroxyalkyldialkyl-phosphorodithioate are added. 0.075% by weight of polymer defoamer and 3.6% by weight of sulfurized olefin are added. Next, Amoco15
Add 0.08% by weight of ashless inhibitor commercially available as 8.

Example 2 Gear oil (especially Exxon base, SAE80W-90)
A gear oil is formulated by initiating a reaction using a base oil formulation utilized in the production of To this base oil composition is added 0.25% by weight of the overbased carboxylate obtained by the method of Example A. Thereafter, 1% by weight of a pour point depressant (maleic anhydride / styrene copolymer) is added. Phosphate ester neutralized with amine 1
%, And 0.75% by weight of an oleamide / linoleamide mixture of hydroxyalkyldialkyl-phosphorodithioate. Add 0.075% by weight of polymer defoamer and 3.6% by weight of sulfurized olefin as antioxidant
Add.

Example 3 A gear oil formulation is prepared by starting with Exxon base SAE80W-90. To this base oil composition is added 0.10% by weight of a borated overbased carboxylate (obtained by reacting the overbased carboxylate of Example B with boric acid). Add. Thereafter, a suitable pour point depressant (especially the reaction product of a maleic anhydride / styrene copolymer with an alcohol and an amine) is added, and a viscosity improver is added in an amount of 1% by weight. 1% by weight of phosphate ester neutralized with amine
Add. 0.075% by weight of polymer defoamer is added and 4.0% by weight of sulfurized olefin are added.

Example 4 A base oil of Exxon base SAE80W-90 was reacted with a borated overbased carboxylate salt by reacting the overbased carboxylate salt of Example C with boric acid. By adding 3.0% by weight of the resulting), a gear oil formulation can be prepared. afterwards,
1.0% by weight of a suitable pour point depressant and 1% by weight of a phosphate ester neutralized with an amine are added. Polymer defoamer
0.1% by weight and 2.0% by weight of the sulfurized olefin are added. Then, 3.0% by weight of dialkyl phosphorodithioate treated with epoxide is added.

Example 5 SEA80W-90 base oil (75% by weight of 600 neutral oils and 1%
A gear oil formulation was prepared by starting with 50 bright stock (containing 25% by weight). To this base oil is added 1% by weight of a pour point depressant, which is in the form of a reaction product obtained by reacting a maleic anhydride / styrene copolymer with ethanol and an amine. An antiwear agent (3% by weight) in the form of a dialkyl phosphorodithioate treated with epoxide was added. 1% by weight of borated calcium carboxylate
0 was added, R-NC ₃ H ₆ N of (R is tallow (tallow)).
1% by weight and 0.075% by weight of a polymeric antifoam were added to complete a gear oil formulation with improved corrosion resistance properties.

Example 6 SEA 80W-90 base oil (75% by weight of 600 neutral oils and 1%
The gear oil formulation was prepared by initiating the reaction with 50 bright stock (containing 25% by weight).
To the base oil, 1% by weight of a reaction product obtained by reacting a maleic anhydride / styrene copolymer with ethanol and an amine was added as a viscosity index improver. An antiwear agent (3% by weight) in the form of a dialkyl phosphorodithioate treated with epoxide was added.
Add 1% by weight of calcium carboxylate and add R-NC ₃ H ₆ N
(R is tallow) 0.1% by weight and polymer defoamer 0.0
75% by weight was added to complete a gear oil formulation with improved corrosion resistance properties.

Example 7 SEA80W-90 base oil (75% by weight of 600 neutral oils and 1%
The gear oil formulation was prepared by initiating the reaction with 50 bright stock (containing 25% by weight).
To the base oil, 1% by weight of a reaction product obtained by reacting a maleic anhydride / styrene copolymer with ethanol and an amine was added as a viscosity index improver. The sulfurized olefin was added in an amount of 3% by weight. An antiwear agent (3% by weight) in the form of a dialkyl phosphorodithioate treated with epoxide was added. 1% by weight of borated calcium carboxylate is added and R-
0.2% by weight of NC ₃ H ₆ N (R is tallow) and 0.075% by weight of a polymeric defoamer were added to complete a gear oil formulation with improved corrosion resistance properties.

Comparative Example 1 This example was prepared in the same manner as Example 7, except that 1% by weight of borated calcium carboxylate was not added to the formulation.

Comparative Example 2 Another comparative example was prepared in the same manner as in Example 7 except that 1% by weight of calcium sulfonate was added to the formulation instead of 1% by weight of the calcium carboxylate added in Example 7. Was prepared.

Comparative Example 3 In the same manner as in Example 7, except that 1% by weight of an acidic corrosion inhibitor was added to the formulation instead of the borated calcium carboxylate added in Example 7, A formulation of a comparative example was prepared.

Comparative Example 4 The same ingredients as in Example 7 were utilized, except that the borated calcium carboxylate of Example 7 was replaced by an additional 1% by weight of basic rust inhibitor to the formulation. Thus, another comparative example was prepared.

The above examples show the use of SAE80W-90 oil as base oil. When preparing gear oils,
SAE 80W-90 oil is preferred. However, 75W oil ~ about 1
40W oil is used and can be used in combination with 150 bright stock oil. The base oil used in preparing the gear oil may be 200 neutral or more, preferably 300N or more, more preferably about 300N or more.
500N to 700N. The viscosity of gear oil base oil is 40 cSt or more at 40 ° C (6 cSt or more at 100 ° C), preferably 60 cSt or more at 40 ° C (100 ° C
At 8 cSt or more). These values are based on the base oil used as a lubricant in the crankcase (eg, about 10
This is exactly the same as the value of about 20 cSt at 0N and 40 ° C (4 cSt at 100 ° C for 5W and 10W base oils).

Gear oil formulations of the present invention typically include a suitable pour point depressant compound. The pour point depressant compound generally comprises from about 0.05% to 4%, more preferably from 0.5% to 2% by weight, based on the weight of the gear oil.
In amounts within the range. Many of the useful pour point depressant compositions are well known and, in oils and fuels,
Used to make these flow freely at low temperatures. Such compounds may typically be composed of the condensation products of chlorinated paraffins and aromatic hydrocarbons (eg, naphthalene). So many different pour point depressants,
And other publications disclosing pour point depressants, 1987
It is disclosed and described in PCT Publication US86 / 02792, published August 30, 1998. (The contents of which are incorporated herein to disclose useful pour point depressant compositions.)

Gear oil formulations of the present invention also typically include a sulfurized olefin compound useful as an antioxidant.
Such compounds typically include an unsaturated olefin compound and a sulfurizing agent (eg, hydrogen sulfide or elemental sulfur).
Are reacted under specific reaction conditions (probably in the presence of a catalyst). Many sulfurized olefin compositions are available from PCT published on December 25, 1986.
It is disclosed in publication US86 / 00884. (These contents are
Shown here to disclose sulfurized olefin compounds).

The PCT publications set forth above also indicate a number of other patents and publications disclosing sulfurized olefin compositions and methods of making the same. Such a sulfurized olefin compound is present in the gear oil in an amount of 0.5% to 10%, more preferably 1% to 5%, even more preferably about 2% by weight, based on the total weight of the gear oil. May be present.

The gear oil formulation of the present invention may also include an extreme pressure agent-antiwear agent therein. Such compounds may be in the form of an attached phosphorus-containing amide. Such compounds are disclosed in issued US Pat. No. 4,670,169. (The contents are hereby incorporated by reference with respect to the disclosure of phosphorus-containing extreme pressure agents and methods for their preparation).

Gear oil formulations of the present invention may also contain minor amounts of other additives, such as antifoams. Antifoams are used to reduce or prevent the formation of stable foam.
Typical defoamers include silicone or organic polymers. Specific antifoam compositions are described in "Foam Control Agents" by Henry T. Kerner (Neusdata Corporation, 1976), pages 125-162.

Amines which can be used in the gear oil formulations of the invention /
In addition to the phosphate compounds, various dithiophosphate compounds (eg, Group II metal salts of dithiophosphoric acids such as zinc dicyclohexyldithiophosphate), and US Pat.
It is possible to use other similar compounds as disclosed in 4,670,169. (The contents of which are hereby incorporated by reference for their disclosure of such dithiophosphate compounds).

In addition to the components set forth above, other additive components such as the following may be included in the gear oil formulation: dispersants, detergents, antioxidants, antiwear agents, extreme pressure agents. Emulsifiers, demulsifiers, friction modifiers, other rust inhibitors and corrosion inhibitors, viscosity improvers, dyes, and solvents for improving handling. These components may be present in various amounts, depending on the needs of the final product of the particular gear oil formulation.

Widely accepted standard tests are available to evaluate the performance of a material to prevent corrosion or rust. 2 of the most widely accepted and accepted standard tests
One is the L-33 wet corrosion test and the turbine oil rust test of ASTM D665 (US Standard Test Material, Book D, No. 665). These tests contain rust inhibitors and corrosion inhibitors, when compared to other gear oils outside the scope of the present invention.
The evaluation of the above invention was shown to be useful.

The L-33 wet corrosion test is first described. Moisture buildup in automotive differential components can create significant rust problems. The Dana Model 30 hypoid rear wheel assembly is used in a specially designed test to evaluate the inherent corrosion resistance of gear lubricants. The capacity of the lubricant is 1.2L (2 1/2 pints). To perform this test, 29.6 cm ³ (1
Oz.) Of distilled water is added to the lubricant. This unit operates at 2500 rpm for 4 hours at a lubricant temperature of 82 ° C. (180 ° F.). After the driving period ends,
The parts are stored at a temperature of 52 ° C. (125 ° F.) for 7 days. Following storage, the unit is disassembled and inspected for rust on cover plate, differential case, gear teeth and bearings. To "pass" the L-33 wet corrosion test, no rust is observed on the gear teeth, bearings, or any other functional part of the rear wheel assembly. The rear wheel assembly cover is more susceptible to rust, and therefore, to achieve a "pass" rating in accordance with the L-33 wet corrosion test, the rusted surface should not exceed 1%. That should be shown. Therefore, if rust is present on any of the functional parts of the rear wheel assembly, or if rust is present on more than 1% of the surface of this cover,
Receive a "Fail" rating. The L-33 wet corrosion test is part of the MIL-L-2105C specification for gear lubricants. This is recognized worldwide as a standard for rust performance.

It is known that when water is incorporated into a lubricant, rust on the ferrous portion can progress rapidly if the lubricant is not sufficiently treated with a suitable rust inhibitor. The ASTM D665 turbine oil rust test is designed to measure the performance of industrial lubricants containing rust inhibitors to prevent rust under water contaminated conditions.

The ASTM D665 test consists of two parts. 1 of this test
One part uses distilled water and the other part
Use synthetic seawater. Both tests are performed under the same conditions and compared. This test uses 300m of test lubricant
The mixture consists of stirring a mixture of l and 30 ml of water at 60 ° (140 ° F) for 24 hours. Certain cylindrical steel specimens (made from # 1018 cold-finished carbon steel) are completely immersed in the test fluid. After 24 hours, the specimens are removed, washed with solvent and evaluated for rust.

To obtain a "pass" according to the ASTM D665 turbine oil rust test, the specimen must be completely free of visible rust when tested under magnification under normal light. When rust is observed, the tested lubricant receives a "fail" rating.

The lubricants included in the present invention were subjected to the L-33 wet corrosion test and the ASTM D665 turbine oil test. For comparison, the same lubricant containing no essential components of the present invention was also tested by the standard method described above. The result looks like this: Comparative Examples 1 to 4 were the same as Example 7 except that the carboxylate component was changed. In this regard, it is believed that these results clearly demonstrate the importance of the present invention with respect to rust prevention.

The present invention is shown and described herein at what is considered to be the most practical and more preferred embodiment. However, it will be appreciated that departures therefrom may be made within the scope of the invention, and that reading of this disclosure will result in obvious modifications by those skilled in the art.

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Claims (8)

(57) [Claims] 1. A gear oil composition comprising a major amount of a base oil having a viscosity at 40 ° C. of 40 cSt or greater; an overbased carboxylate; and a sulfided olefin, wherein the overbased A composition wherein the carboxylate is borated and wherein the composition contains from 0.1% to 5% by weight of impure water. 2. The overbased carboxylate according to claim 1, wherein
A carboxylic acid having ~ 22 carbon atoms, and calcium,
The gear oil composition according to claim 1, obtained by reacting with a neutralizing agent containing a metal selected from the group consisting of sodium and magnesium. 3. The overbased carboxylate is present in an amount ranging from 0.1% to about 3% by weight, based on the weight of the gear oil, and the carboxylic acid is
The gear oil composition according to claim 2, wherein the gear oil composition is selected from the group consisting of tall oil fatty acids, oleic acid, linoleic acid, palmitic acid, stearic acid and lauric acid. 4. A major amount of a base oil having a viscosity of 40 cSt or more at 40 ° C .; a statistical mixture of carboxylic acids or thiocarboxylic acids represented by the following general formula (IV): calcium, sodium and magnesium A statistical mixture of overbased carboxylate or thiocarboxylate formed by reacting a stoichiometric excess of a neutralizing agent containing a metal selected from the group consisting of: A gear oil composition comprising: an olefin, comprising: Wherein R ^* is an aliphatic hydrocarbon-based group having at least 4 carbon atoms and no more than 400 aliphatic carbon atoms, a is an integer from 1 to 4, and Ar ^* is ,14
A polyvalent aromatic hydrocarbon nucleus having up to carbon atoms, each X
^* Is independently a sulfur or oxygen atom, and m
Is an integer from 1 to 4, provided that (R ^* ) _a is a group of formula IV
Has a total of at least 8 aliphatic carbon atoms for each acid molecule represented by the formula: React to form a statistical mixture of borated overbased carboxylate or thiocarboxylate, and wherein the composition contains 0.1% to 5% by weight of impure water ,Composition. 5. The gear oil composition according to claim 4, wherein said borating agent is boric acid. 6. A method for improving the corrosion resistance of a gear oil composition, wherein the gear oil composition comprises a major amount of a base oil having a viscosity at 40 ° C. of 40 cSt or more, and a weight of the gear oil composition. Containing from 0.1% to 5% by weight of impure water, based on the method, comprising: borating an overbased carboxylate or thiocarboxylate; 0.1% by weight to the gear oil composition; Adding about 3% by weight of the borated overbased carboxylate or thiocarboxylate; and to improve the corrosion resistance of the gear oil, the borated overbased throughout the oil. A method comprising admixing a carboxylic acid salt or a thiocarboxylic acid salt. 7. The borated overbased carboxylate or thiocarboxylate comprises a statistical mixture of a carboxylic acid or a thiocarboxylic acid represented by the following general formula (IV): calcium, sodium and magnesium. Reacting with a stoichiometric excess of a metal-containing neutralizing agent selected from the group consisting of: and borating the reactants to form a borated overcoat. 7. The method of claim 6, wherein the method is a statistical mixture of a base carboxylate or a thiocarboxylate. Wherein R ^* is an aliphatic hydrocarbon-based group having at least 4 carbon atoms and no more than 400 aliphatic carbon atoms, a is an integer from 1 to 4, and Ar ^* is ,14
A polyvalent aromatic hydrocarbon nucleus having up to carbon atoms, each X
^* Is independently a sulfur or oxygen atom, and m
Is an integer from 1 to 4, provided that (R ^* ) _a is a group of formula IV
Has at least 8 aliphatic carbon atoms for each acid molecule represented by 8. The statistical mixture of the borated overbased carboxylate or thiocarboxylate comprises:
The method according to claim 7, wherein the amount is added in the range of 0.2% to 1.5% by weight, based on the weight of the gear oil.