CA1290314C

CA1290314C - Lubricant composition containing transition metals for viscosity control

Info

Publication number: CA1290314C
Application number: CA000526872A
Authority: CA
Inventors: David E. Ripple
Original assignee: Lubrizol Corp
Current assignee: Lubrizol Corp
Priority date: 1986-01-21
Filing date: 1987-01-07
Publication date: 1991-10-08
Anticipated expiration: 2008-10-08
Also published as: DE3788345T2; DK489487D0; AU604678B2; EP0290457A1; DE3788345D1; JPH01501396A; MX169569B; NO873690L; HK96694A; FI883438A; NO174347B; ZA87280B; EP0290457B1; FI883438A0; DK489487A; NO174347C; IN167977B; BR8707574A; CN87100331A; NO873690D0

Abstract

ABSTRACT

This invention describes lubricants containing a minor amount of an oil-soluble or oil-dispersible metallic compound which retards viscosity rate increase build-up in a high soot environment.

Description

1290:~.4 BACKGROUND OF THE INVENTION

1. Field of the Invention This invention relates to lubricant compositions and, in particular, to viscosity control of the lubricant in a diesel engine.

2. Description of the Art Lubricants, particularly lubricants for diesel engines used in low speed, high torque operations, suffer from a viscosity build-up over time. This viscosity build-up is manifested in that the lubricant within the diesel engine begins a gradual viscosity rise and that the rate of viscosity increase accelerates with time.
Eventually, the viscosity increase becomes sufficiently high and the oil flow within the engine will be restricted.
A second factor is that the lubricant in the sump gradually t~ickens and becomes unavailable for lubrication. When the thickened lubricant does not pass the oil pump inlet, engine damage results.
The viscosity build-up thus can lead to unacceptable wear in the engine, particularly in a cold climate. The main preventative technique for avoiding damage from excessive viscosity build-up is to drain a small amount of oil from the sump and to observe the viscosity of the lubricant. The problem then becomes the determination of the correct interval for checking the sump. As the rate : of change in viscosity accelerates, the intervals for checking lubricant viscosity must become more closely spaced to ensure that engine damage does not occur.
It has been stated in a paper entitled, Oil Thickening In the Mack T-7 Enqine Test by Covitch, Humphrey and Ripple, that various compounds may be added to a diesel lubricant to limit oil thickening. The Covitch et al paper was presented at the SAE Fuels and lubricants meeting, Tulsa, Oklahoma on October 23, 1985.
The Covitch et al paper teaches that soot, which is 12~ 4 produced as an incomplete combustion product in diesel engines, finds its way into the lubricating oil. The presence of soot in the crankcase has been linked to viscosity increase and viscosity rate increase in the lubricants.
United States Reissue Patent 29,661 which was granted on June 6, 1978 to Hendrickson describes a test composition comprising SAE neutral refined oil containing a succinimide dispersant, calcium phenates and as an oxidation catalyst, a solution of metal naphthenates in kerosene including copper, iron, tin, manganese and lead. The purpose of including the metals in the Hendrickson patent is apparently to rapidly increase the oxidation of ~ 2~()314 l:he oil as a part of a test of the effectiveness of the dispersant employed.
United States Patent 4,529,408 issued July 16, 1985 to Yan suggests that coal combustion may be improved, ash corrosion modified, and fouling and ash slagging reduced by including a metal at a few parts per thousand with coal. The materials suggested by Yan include a member selectPd from the group consisting of manganese dioxide, iron oxide, manganese nodules, sand and mixtures thereof.
Johnson, in United States Patent 4,411,774 issued October 25, 1983 suggests that waste oil contains in parts per million concentration various metals including tin, lead, copper, aluminum, iron, chromium, zinc, magnesium, nickel, barium, sodium, calcium, vandium, molybdenum, boron and manganese. The waste oil, according to Johnson, also may contain silicon, phosphorus and possibly silver.
Hotten, in United States Patent 4,049,562, issued September 20, 1977 suggests that the anti-oxidant activity of an oil may be tested in the presence of a solution containing the naphthenates of copper, iron, manganese, lead and chromium. It is further stated by Hotten that this distribution of metals would be e~pected to be found in a used crankcase oil from a diesel engine.
Various transition metals as o~idation inhibitors are described in United States Patent 4,122,033 issued October 24, 1978 to Black. Watson, in United States Patent 3,652,616 issued March 28, 1972 describes fuel and lubricant compositions containing metals such as zinc, manganese, chromium, copper, cobalt, vanadium, titanium, molybdenum, silver, cadmium, tungsten or mercury. The use of copper as an anti-oxidant in lubricants in disclosed in European application 0024 146 to Colelough published February 25, 1981.
It has been found in the present invention that relatively small amounts of certain transition metals may be utilized in an oil-soluble form in a diesel lubricant composition to substantially reduce the soot related ~290~3~.4 viscosity increase and the viscosity rate increase (acceleration). The compositions of the present invention are particularly effective in diesel oils which are sub~ect to rapid viscosity build-up.
Throughout the specification and claims, percentages and ratios are by weight, temperatures are in degrees Celsius and pressures are in KPa gauge unless otherwise indicated.

SUMMARY OF THE INVENTION

A first aspect of the invention is a lubricant composition comprising an oil of lubricating viscosity, a dispersant, and a minor amount of an oil-soluble or oil-dispersible metallic compound in an amount sufficient to retard soot related viscosity rate increase of the oil when utilized in a diesel engine wherein the metallic compound contains a metal,selected from the group consisting of manganese, titanium, cobalt, copper, vanadium, nickel, tungsten, molybdenum, and chromium, and mixtures thereof.
A preferred embodiment of the invention is a lubricant composition comprising a major amount of an oil of lubricating viscosity and about 30 ppm to about 500 ppm as the metal of an oil-soluble or oil-dispersible metallic compound capable of retarding soot related viscosity rate increase of the oil when utilized in a diesel engine wherein the metallic compound contains a metal selected from the group consisting of manganese, titanium, cobalt, chromium, vanadium, nickel, tungsten, molybdenum, and mixtures thereof.
A second aspect of the invention is a process for retarding soot related viscosity rate increase of a lubricant in a lubricating system prone to soot build-up comprising the steps of introducing to a lubricant a metallic compound wherein the metal is selected from the 12~ 4 group consisting of manganese, titanium, cobalt, copper, ~anadium, nickel, tungsten, chromium, and molybdenum, and mixtures thereof in an amount sufficient to retard the viscosity rate increase.
DETAILED DESCRIPTION OF THE INVENTION
Basically, this invention is a composition comprising a polyvalent metal compound and a diesel lubricating oil.
The metallic compound includes both organic and inorganic forms of manganese, copper, nickel, vanadium, titanium, tungsten, cobalt, chromium, molybdenum and mixtures thereof. Preferably, the metallic compound contains manganese or titanium. Also useful herein are the metallic phenates, salicylates, phosphonates, dithiocarbamates and napthanetes. The napthanetes are a preferred species of the metallic compound.
The inorganic compounds include, for example, the oxides, hydroxides, and carbonates. Organic and inorganic metal compounds are useful in mixtures within the present invention. The amount of metal employed should be sufficient to retard the viscosity rate increase between 100 and 150 hours in the Mack T-7 test. The viscosity rate increase slope should then be less than 0.1, preferably less than 0.08 during the 100 to 150 hour interval.
The preferred organic compounds useful for the metallic components are conveniently salts of at least one organic acid. While mixtures of organic and inorganic metal components are useful, it is highly desired that an organic metallic compound be employed to assist in dispersing the metal compound in the lubricant.
The organic acids used to make the salts for the metallic compound include carboxylic acids, particularly those containing from 1 to 30 carbon atoms, e.g., the carboxylates, sulfonic acids, particularly those containing an aromatic ring structure (e.g., benzene ring) substituted with one or more alkyl groups of 4 to about 30 carbon atoms, e.g., a sulfonate, and phosphorus acids, i2~ 4 containing within their structures one or more organic groups of 1 to about 30 or more carbon atoms. Preferably, the organic acid is a mixture of organic acids containing an average of at least 7 carbon atoms, conveniently about 4 to about 30, preferably 6 to 30 total carbon atoms per carboxyl group.
Such carboxylic, sulfonic and phosphorus acids are well known to the art. The carboxylic acids can be mono-or polycarboxylic acids (if the latter, typically they are di- or tricarboxylic acids).
Monocarboxylic acids include C1_7 lower acids (acetic, proprionic, etc.) and higher C8~ acids (e.g., octanoic, decanoic, etc.) as well as the fatty acids of about 12-30 carbon atoms. The neo acids such as neooctanoic and neodecanoic and the like are also useful.
The fatty acids are often mixtures of straight and branched chain acids containing, for example, from 5% to about 30% straight chain acids and about 70% to about 95~
(mole) branched chain acids. Other commercially available fatty acid mixtures containing much higher proportions of straight chain acids are also useful. Mixtures produced from dimerization of unsaturated fatty acids can also be used.
Higher carboxylic acids include the well known dicarboxylic acids made by alkylating maleic anhydride or its derivatives. The products of such reactions are hydrocarbon substituted succinic acids, anhydrides, and the like. Lower molecular weight dicarboxylic acids, such as polymethylene bridged acids (glutaric, adipic, and the like), can also be used to make the salts of this invention as well as the lower molecular weight substituted succinic acids such as tetrapropenyl succinic acid and its analogs of to about C30 substituted acids.
Higher molecular weight substituted succinic anhydrides, acids, and analogs useful in making the salts of this invention have been described in a number of patents, particularly those dealing ~ith acylated ~ 2~ .4 compounds useful as dispersants. Typical high molecular we~ght acids are those made by reacting a poly(isobutene) Eraction having between 30 and 400 (usually 50-250) carbon atoms with maleic anhydride. Such materials are described in U.S. Patents 3,172,892 issued to Le Suer et al on March 9, 1965, 3,219,666 issued to Norman et al on November 23, 1965, and 3,272,746 issued to Le Suer et al on September 13, 1966. Other monocarboxylic acids of similar molecular weight can be made by alkylating acrylic acid and its analogs. Mixtures of such acids can also be used.
The useful metallic compounds of this invention can also be made from carboxylic acids and even acidic hydroxy co~pounds such as alkylated phenols. Such materials are disclosed in U.S. Patent 4,100,082 issued to Clason et al on July 11, 1978, particularly columns 15-17.
Typically the organic acids used to make the salts of this invention are carboxylic acids, sulfonic acids, or mixtures thereof, or compounds containing both functional groups.
The sul~onic acids used to form the metallic compound include the aliphatic sulfonic acids. Examples of such sulfonic acids are mahogany sulfonic acids; bright stock sulfonic acids; sulfonic acids derived from lubricating oil fraction having a Saybolt Viscosity from about 100 seconds at 37C to about 200 seconds at 99C; petrolatum sulfonic acids; mono- and polywax substituted sulfonic and polysulfonic acids of, e.g., benzene, naphthalene, phenol, diphenyl ether, naphthalene disulfide, diphenyl amine, thiophene, alpha-chloronaphthalene, etc.; other substituted sulfonic acids such as alkyl benzene sulfonic acids (where the alkyl group has at least 8 carbons), cetylphenyl mono-sulfide sulfonic acids, dicetyl thianthrene disulfonic acids, dilauryl beta-naphthyl sulfonic acids, dicapryl nitronaphthalene sulfonic acids and alkaryl sulfonic acids such as dodecylbenzene (bottoms) sulfonic acids. Dodecylbenzene (bottoms) are principally mixtures of mono- and di-dodecylbenzenes.

~2~0~

The aliphatic sulfonic acids include paraffin wax sulfonic acids, unsaturated paraffin wax sulfonic acids, hydroxy-substituted paraffin wax sulfonic acids, hexapropylene sulfonic acids, tetra-amylene sulfonic acids, polyisobutene sulfonic acids wherein the polyisobutene contains from 20 to 7000 or more carbon atoms chloro-substituted paraffin wax sulfonic acids, nitro-paraffin wax sulfonic acids, etc., cycloaliphatic sulfonic acids such as petroleum naphthene sulfonic acids, cetyl cyclopentyl sulfonic acids, lauryl cyclohexyl sulfonic acids, bis-(di-isobutyl) cyclohexyl sulfonic acids, mono- or poly-wax substituted cyclohexyl sulfonic acids, etc.
Further details concerning sulfonic acids used herein can be found in U.S. Patents PATENT INVENTOR ISSUE DATE

2,616,905 Asseff et al November 4, 1952 3,027,325 McMillen et al March 27, 1962 3,312,618 Le Suer et al April 4, 1967 3,350,308 McMillen et al October 31, 1967 3,471,403 Le Suer et al October 7, 1969 3,488,284 Le Suer et al January 6, 1970 3,595,790 Norman et al July 27, 1971 3,798,012 Le Suer March 19, 1974 3,829,381 Le Suer August 13, 1974 4,100,083 Ripple August 22, 1978 4,326,972 Chamberlin April 27, 1982 The useful salts of this invention can be made from phosphorus acids. Such phosphorus acids have been disclosed in a number of U.S. patents and other literature. Exemplary of the former is U.S. Patent ~2~

4,191,658 to Jahnke issued March 4, 1980, which discloses phosphorus acid salts of the formula Rl(Xl)a ll \ 11 4 P-X M
/

R (X )b /

wherein M is the aforementioned metal of the metallic compound or mixtures thereof; each Rl and R2 is a hydrocarbon xadical; each of Xl, X , X3 and X4 is oxygen or sulfur; and each of a and b is 0 or 1.
The salts made from organic acids can be prepared by reacting the organic acid with the metal, preferably manganese, for example, such as manganese oxide, manganese hydroxide, manganese carbonate, cupric o~ide, cupric hydroxide and cupric carbonate.
A particularly preferred method of obtaining the metallic co~pound are as the overbased salts. Overbased salts are those salts of organic acids which contain more than sufficient metal to neutralize the acid present. In other words, they contain in excess of one equivalent of metal per equivalent of acid derived moiety. Such salts are known to the art. For disclosures on overbasing in general, see, for example, U.S. Patent 3,827,979 to Piotrowski et al; U.S. Patent 3,312,618 to Le Suer et al issued April 4, 1967; U.S. Patent 2,616,904 and 2,616,905 to Asseff issued November 4, 1952; U.S. Patent 2,595,790 to Norman et al; and U.S. Patent 3,725,441 to Murphy et al issued April 3, 1973. For specific disclosures of overbased manganese and copper salts of organic acids, see U.S. Patents 2,695,910 issued November 30, 1954, to Asseff et al and 4,162,986 issued July 31, 1979, to Alkaitis et al.
In particular, this invention relates to manganese salts of organic acids -~hich are hydrocarbon-soluble.

~0~.4 ~ighly overbased manganese metal organic compositions c:omprising a manganese oxide-hydroxide-carboxylate complex herein the metal content is in chemical combination partly with oxygen in a polynuclear metal oxide crystallite core and partly with at least two different monocarboxylic acids or a mixture of one or more monocarboxylic and monosulfonic acids containing at least two carbon atoms as hydroxyl-metal-carboxylate and hydroxyl-metal sulfonate groups. See, for example, U.S.
Patent 4,191,658 issued March 4, 1980, to Jahnke.
The compositions of this invention are preferably those which are hydrocarbon soluble. As used in the specification and the appended claims, the term "hydrocarbon soluble" is intended to mean that the compositions are soluble or stably dispersible in normally liquid hydrocarbons. The term "stably dispersible" as u~ed in the specification and the appended claims is intended to mean that the composition is capable of being dispersed in the lubricant to an extent which allows it to function in its intended manner. Thus, for example, a composition is hydrocarbon soluble if it is capable of being suspended in a lubricating oil in a manner sufficient to allow the oil to function as a lubricant.
The combination of the oil, the metallic compound and the dispersant can be effected in any convenient manner.
Where both copper and manganese are employed a ratio of about 0.05 up to about 23 g-atoms, preferably, from about 2 up to about 23 and, more preferably, from about 4 up to about 20 g-atoms of manganese for each g-atom of copper is employed in the composition. Mixtures of manganese and titanium, manganese and cobalt, and titanium and cobalt are also useful herein. Suggested metal molar ratios of the foregoing binary combinations are about 15:1 to 1:15, preferably about 10:1 to 1:10 of the first metal to the second metal.
The invention also contemplates the use of other additives. Such additives include, for example, ~ 2~ .4 detergents and dispersants of the ash-producing or ashless type.
The ash-producing detergents are exemplified by oil-soluble neutral and basic salts of alkali or alkaline earth metals with sulfonic acids, carboxylic acids, or organic phosphorus acids characterized by at least one direct carbon-to-phosphorus linkage such as those prepared by the treatment of an olefin polymer (e.g., polyisobutene having a molecular weight of 1000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and a sulfur halide, or phosphorothioic chloride. The most commonly used salts of such acids are those of sodium, potassium, lithium, calcium, magnesium, strontium and barium.
The term "basic salt" is used to designate metal salts wherein the metal is present in stoichiometrically larger amounts than the organic acid radical. The commonly employed methods for preparing the basic salts involve heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate, bicarbonate, or sulfide at at a temperature about 50C and filtering the resulting mass.
The use of a "promoter" in the neutralization step to aid the incorporation of a large excess of metal likewise is known. Examples of compound useful as the promoter include phenolic substances such as phenol, naphtol, alkylphenol, thiophenol, sulfurized alkyphenol, and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octyl alcohol, cellosolve, carbitol, ethylene glycol, stearyl alcohol, and cyclohexyl alcohol, and amines such as aniline,- phenylenediamine, phenothiazine, phenyl-beta-naphthylamine, and dodecylamine. A
particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic ~2~0~3~.4 alkaline earth metal neutralizing agent and at least one alcohol promoter, and carbonating the mixture at an elevated temperature such as 60-200C.
Ashless detergents and dispersants are so called despite the fact that, depending on its constitution, the dispersant may upon combustion yield a non-volatile material such as boric oxide or phosphorus pentoxide;
however, it does not ordinarily contain metal and therefore does not yield a metal-containing ash on combustion. Many types are known in the art, and any of them are suitable for use in the lubricant compositions of this invention. The following are illustrative:
(1) Reaction products of carboxylic acids (or derivatives thereof) containing at least about 30 and preferably at least about 50 carbon atoms with nitrogen containing compounds such as amine, organic hydroxy compounds such as phenols and alcohols, and/or basic inorganic materials. E~ample~ of these "carboxylic dispersants" are describe~ in British Patent 1,306,529 and in many U.S. patents including the following:

PATENT INVENTOR ISSUE DATE

3,163,603 Le Suer December 29, 1964 3,184,474 3,215,707 Rense November 2, 1965 3,219,666 Norman et al November 23, 1965 3,271,310 Le Suer September 6, 1966 3,272,746 Le Suer et al September 13, 1966 3,281,357 Vogel October 25, 1966 3,306,908 Le Suer February 28, 1967 3,311,558 Prizer et al March 28, 1967 3,316,177 Dorer April 25, 1967 3,340,281 Brannen September 5, 1967 3,341,542 Le Suer et al September 12, 1967 3,346,493 Le Suer October 10, 1967 ~2~03~.`4 3,351,552 Le Suer November 7, 1967 3,381,022 Le Suer April 30, 1968 3,399,141 Clemens August 27, 1968 3,415,750 Anzenberger December 10, 1968 3,433,744 Le Suer March 18, 1969 3,444,170 Norman et al May 13, 1969 3,448,048 Le Suer June 3, 1969 3,448,049 Preuss et al June 3, 1969 3,451,933 Leister June 24, 1969 3,454,607 Le Suer July 8, 1969 3,467,668 Gruber et al September 16, 1969 3,501,405 Willette March 17, 1970 3,522,179 Le Suer July 28, 1970 3,541,012 Stuebe November 17, 1970 3,542,680 Le Suer November 24, 1970 3,543,678 3,567,637 Sabol March 2, 1971 3,574,101 Murphy April 6, lg71 3,576,743 Widmer et al April 27, 1971 3,630,904 Musser et al December 28, 1971 3,632,510 Le Suer January 4, 1972 3,632,511 Chien-Wei Liao January 4, 1972 3,697,428 3,725,441 Murphy April 3, 1973 4,234,435 Meinhardt November 18, 1980 Re 26,433 Le Suer August 6, 1968 (2) Reaction products of relatively high molecular weight aliphatic or alicyclic halides with amines, preferably polyalkylene polyamines. These may be characterized as "amine dispersants" and examples thereof are described for example, in the following U.S. patents:
PATENT INVENTOR ISSUE DATE

3,275,554 3,438,757 3,454,555 vander Voort et al July 8, 1969 3,565,804 Honnen et al February 23, 1971 ~2~03~.4 (3) Reaction products of alkyl phenols in which the alkyl group contains at least about 30 carbon atoms with aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines), which may be characterized as "Mannich dispersants". The materials described in the following U.S. patents are illustrative:
PATENT INVENTOR ISSUE DATE

2,459,112 Oberright January 11, 1949 2,962,442 Andress November 29, 1960 102,984,550 Chamot May 16, 1961 3,036,~03 Verdol May 27, 1962 3,166,516 3,236,770 Matson February 22, lg66 3,355,270 Amick November 28, 1967 153,368,972 Otto Fe~ruary 13, 1968 3,413,347 Worrel November 26, 1968 3,442,808 Traise May 6, 1969 3,448,047 Traise June 3, 1969 3,454,497 Wittner July 8, 1969 203,459,661 Schlobohm August 5, 1969 3,461,172 3,493,520 Verdol et al February 3, 1970 3,539,633 Piasek et al November 10, 1970 3,558,743 Verdol et al January 26, 1971 253,586,629 Otto et al June 22, 1971 3,591,598 Traise et al July 6, 1971 3,600,372 Udelhofen et al August 17, 1971 3,634,515 Piasek et al January 11, 1972 3,649,229 303,697,574 Piasek et al October 10, 1972 3,725,277 Worrel April 3, 1973 3,725,480 Traise et al April 3, 1973 3,726,882 Traise et al April 10, 1973 3,980,569 Pindar et al September 14, 1976 ~4) Products obtained by post~treating the carboxylic, amine or Mannich dispersants with such ~2~03~.4 reagents as urea, thiourea, carbon disulfide, aldehydes, }setones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, phosphorus compounds or the like. Exemplary materials of this kind are described in the following U.S. patents:
PATENT INVENTOR ISSUE DATE

3,036,003 Verdol May 22, 1962 3,087,936 Le Suer April 30, 1963 3,200,107 Le Suer August 10, 1965 3,216,936 Le Suer November 9, 1965 3,254,025 Le Suer May 31, 1966 3,256,185 Le Suer June 14, 1966 3,278,550 Norman et al October 11, 1966 3,280,234 3,281,428 Le Suer October 25, 1966 3,282,955 Le Suer November 1, 1966 3,312,619 Dale April 4, 1967 3,366,569 Norman et al January 30, 1968 3,367,943 3,373,111 Le Suer et al March 12, 1968 3,403,102 Le Suer September 24, 1968 3,442,808 Traise et al May 6, 1969 3,455,831 3,455,832 3,493,520 Verdol et al Februar~ 3, 1970 3,502,677 Le Suer March 24, 1970 3,513,093 Le Suer May 19, 1970 3,533,945 Vogel October 13, 1970 3,539,633 Piasek et al November 10, 1970 3,573,010 Mehmedbasich March 30, 1971 3~579,450 Le Suer May 18, 1971 3,591,598 Traise July 6, 1971 3,600,372 3,639,242 Le Suer February 1, 1972 3,649,229 3,649,659 Otto et al March 14, 1972 3,658,836 Vineyard April 25, 1972 3,697,574 Piasek et al October10, 1972 3,702,757 3,703,536 3,704,308 3,708,422 Swanson January2, 1973 (5) In~erpolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight olefins with monomers containing polar substituents, e.g., aminoalkyl acrylates or acrylamides and poly-(oxyethylene)-substituted acrylates. These may be characterized as "polymeric dispersants" and examples thereof are disclosed in the following U.S. patents:
PATENT INVENTOR ISSUE DATE

3,329,658 Fiel~s July 4, 1967 3,449,250 3,519,565 Coleman July 7, 1970 3,666,730 Coleman May 30, 1972 3,687,849 Abbott August 29, 1972 3,702,300 Coleman November 7, 1972 As previously mentioned, the compositions of the present invention are useful as additives for diesel lubricants. Generally, these lubricant compositions comprise a major amount of an oil of lubricating viscosity and a minor amount of the manganese or other metallic compound of the present invention.
The term "minor amount" as used in the specification and appended claims is intended to mean that when a composition contains a "minor amount" of a specific material that amount is less than 50~ by weight of the composition.
The term "major amount" as used in the specification and appended claims is intended to mean that when a composition contains a "major amount" of a specific .4 material that amount is more than 50% by weight of the composition.
Typically, the amount of the metallic compound to the lubricant oil in the compositions of this invention is such that the treated lubricant compositions have the metal present at about 30 ppm to 500 ppm, preferably 35 ppm to 350 ppm, and most preferably about 40 ppm to about 150 ppm by weight of the composition.
The oil of lubricating viscosity which is utilized in the preparation of the diesel lubricants of the invention may be based on natural oils, synthetic oils, or mixtures thereof.
Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful.
Synthetic lubricating oils include hydrocarbon oils and halosubstituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypyropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, etc.); poly(1-hexenes), poly(l-octenes), poly(1-decenes), etc. and mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes, etc.), polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.);
alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils that can be used. These are exemplified ~2~0~.4 by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methylpolyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3-C8 fatty acid esters, or the C13oxo acid diester of tetraethylene glycol.
Another suitable class of snythetic lubricating oils that can be used comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acidl alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.
Esters useful as synthetic oils also include those made from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripenta-erythritol, etc.
Silicon-based oils such as the polyalkyl~, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants ~ 2~0~.4 (e.g., tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate, tetra-(4-methyl-hexyl)-silicate, tetra-(p-tert-butyl-phenyl)silicate, hexyl-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxans, poly(methylphenyl)siloxanes, etc.~. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioxtyl phosphate, diethyl ester of decane phosphonic acid, etc.), polymeric tetrahydrofurans and the like.
Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the concentrates of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil.
Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, hydrotreating, hydrocracking, acid or base extraction, filtration, percolation, etc.
Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.
Most preferably, the oil used herein is a petroleum derived oil. Coincidently, the greatest effects of the various metals used herein are found in petroleum derived o i 1 s .

~ 2~0~ 4 The effect of soot related viscosity increase and viscosity rate increase on the lubricant may be retarded by periodically adding a portion of fresh lubricant treated with the metals according to the present invention. Thus, an initially untreated (metal) lubricant may enjoy the benefits herein by using a treated lubricant for replacement between oil changes. The metallic compound may also be added to the crankGase in the presence of a diluent oil wherein the metallic compound is present in a 1 to 25 fold excess (as the metal) over that normally found in the oil. In this manner, a diesel crankcase containing twenty to twenty-five liters of untreated oil is brought up to the correct metallic compound level by adding as little as one liter of additive.
The lubricant oil is typically utilized in the invention at about 75% to about 99.5% by weight of the composition, preferably about 80% to about 99% by weight.
The diluent oils (lubricants) present as various additives are included in the above amounts. The dispersant as previously discussed is conveniently utilized at about 0.05% to about 20~ by weight, preferably about 0.1% to about 15% by weight of the composition.
The diesel lubricating compositions utilized herein are preferably substantially free of lead, iron, aluminum or tin in any form. The absence of the aforementioned metals is desired because they are wear metals, or materials which normally comprise a portion of the engine.
The presence of wear metals during analysis by a fleet owner usually indicates a problem of wear in the engine.
Thus, wear metals are desirably not included in a lubricant as these materials reduce the reliability of the analytical methods used to detect wear. The metals described as being undesirable also have the potential to act as oxidation catalysts which can result in oil oxidation thus requiring premature oil changes.

1 2~0~3~ 4 The total base number of the diesel lubricant is typically between O and 25, preferably between 1 and 15.
The total base number indicates that the lubricant is capable of withstanding changes toward acid build-up.
Acid build-up causes increased corrosion and a higher base-number represents resistance to acid build-up.
In a preferred embodiment, the diesel lubricants of the present invention also contain at least one oil-soluble neutral or basic alkaline earth metal salt of at least one acidic organic compound. Such salt compounds generally are referred to as ash-containing detergents.
The acidic organic compound may be at leas~ one sulfur acid, carboxylic acid, phosphorus acid, phenol, salicylate or mixtures thereof.
Calcium, magnesium and barium are the preferred alkaline earth metals. Salts containing A mixture of ions of two or more of these alkaline earth metals can be used.
The salts which are useful can be neutral or basic.
The neutral salts contain an amount of alkaline earth metal which is just sufficient to neutralize the acidic groups present in the salt anion, and the basic salts contain an excess of the alkaline earth metal cation.
The amount of the alkaline earth metal salt included in the diesel lubricants of the present invention also may be varied over a wide range, and useful amounts can be readily determined by one skilled in the art. The salt functions as an auxiliary or supplemental detergent. The amount of the alkaline earth metal salt diesel lubricant of the invention may vary from about 0% to about 5~ or more, preferably 0.5~ to 4% by weight of the composition.
The present invention also contemplates the use of other additives in the diesel lubricant compositions of the present invention. These other additives include such conventional additive types as anti-oxidants, extreme pressure agents, corrosion-inhibiting agents, pour point depressants, color stabilizing agents, anti-foam agents, and other such additive materials known generally to those 0~ 4 s~illed in the art of formulating diesel lubricants.
Where anti-oxidants are employed, it is preferred that the anti-oxidant be of the amine type such as an alkylated aryl amine. Preferably, the t-butyl hindered phenolics are not employed in the present invention. If used, the hindered phenolic should be employed with a second anti-oxidant.
Extreme pressure agents and corrosion- and oxidation-inhibiting agents are exemplified by chlorinated aliphatic hydrocarbons such as chlorinated was; organic sulfides and polysulfides such as benzyl disulfide, bis(chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized alkylphenol, sulfurized dipentene, and sulfurized terpene;
phosphosulfurized hydrocarbons such as the reaction product of a phosphorus sulfide with turpentine or methyl oleate; phosphorus esters including principally dihydrocarbon and trihydrocarbon phosphites such as dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentyl phenyl phosphite, dipentyl phenyl phosphite, tridecyl phosphite, distearyl phosphite, dimethyl naphthyl phosphite, oleyl 4-pentylphenyl phosphite, polypropylene (molecular weight 500)-substituted phenyl phosphite, diisobutyl-substituted phenyl phosphite; metal thiocarbamates, such as zinc dioctyldithiocarbamate, and barium heptylphenyl dithio-carbamate; Group II metal phosphorodithioates such as zinc dicyclohexylphosphorodithioate, zinc dioctylphosphoro-dithioate, barium di(heptylphenyl)-phosphorodithioate, cadmium dinonylphosphorodithioate, and the zinc salt of a phosphorodithioic acid produced by the reaction of phosphorus pentasulfide wih an equimolar mixture of isopropyl alcohol and n-hexyl alcchol.
Many of the above-mentioned auxiliary extreme pressure agents and corrosion-oxidation inhibitors also serve as antiwear a~ents. Zinc dialkylphosphorodithioate compounds are a well known example.

~2~0~ 4 Pour point depressants are a particularly useful type of additive often included in the lubricating oils described herein. The use of such pour point depressants in oil-based compositions to improve low temperature properties of oil-based compositions is well known in the art. See, for example, page 8 of "Lubricant Additives" by C.V. Smalheer and R. Kennedy Smith (Lezius-Hiles Co.
publishers, Cleveland, Ohio, 1967).
Examples of useful pour point depressants are poly-methacrylates; polyacrylates; polyacrylamides;condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkylfumarates, vinyl esters of fatty acids and alkyl vinyl ethers. Pour point depressants useful for the purposes of this invention, techniques for their preparation and their uses are described in the following U. S. Patents:

PATENT INVENTOR ISSUE DATE
2,387,501 2,015,748 2,655,479 1,815,022 2,191,498 Reiff February 27, 1940 2,666,746 2,721,877 2,721,878 3,250,715 Wyman May 10, 1966 Anti-foam agents are used to reduce or prevent the formation of stable foam. Typical anti-foam agents include silicones or organic polymers. Additional anti-foam compositions are described in "Foam Control Agents", by Henry T. Kerner (Noyes Data Corporation, 1976), pages 125-162.
Viscosity improvers are typically included at about 5~ to about 15% by weight of the composition. The viscosity improvers function to maintain more or less ~l 2~0~3~.4 constant viscosity as the lubricant temperature is increased. Examples of viscosity improvers are hydrogenated styrene-isoprene copolymers; maleic anhydride styrene copolymers; olefin copolymers such as ethylene-propylene copolymers; styrene butadiene copolymers andhomopolymers such as polybutylene.
The present invention will be further understood by a consideration of the following examples which are intended to be purely exemplary of the invention. Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the following.

~0~

EXAMPLE I

A fully formulated lubricant composition is prepared containing:
COMPONENTS PARTS

Mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 Manganese as its sulfonate from 50 ppm dialkylated benzene having an average alkyl benzene molecular weight between 300 and 380 reported as manganese metal The product of Example I gave a Mack T-7 test result slope of 0.018 between 100 and 150 hours of operation. A
passing slope value under the current Mack T-7 test is 0.04 or less. The same formulation without the manganese gave a test value of 0.16.

12903~.4 EXAMPLE II

A fully formulated lubricant composition is prepared containing:
COMPONENTS PARTS

Mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 Manganese oxide, hydroxide, and carboxylate 40 ppm (neodecanoate) as manganese This formulation gave a Mack T-7 slope test result of 0.035 where 0.04 is passing. The test slope value in the absence of the manganese is 0.16.

~290~3~ 4 EXAMPLE III

A fully formulated lubricant composition is prepared containing:
COMPONENTS PARTS

Mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 Cobalt as a napthenate 50 ppm The cobalt containing formulation gives a Mack T-7 test slope ~alue of 0.068 and shows an improvement of greater than 50% over the formulations not containing cobalt. The viscosity increase in the lubricant is 58%
greater over the interval of 100 to 150 hours in the absence of cobalt.

~2~03~.4 EXAMPLE IV

A fully formulated diesel lubricant composition is prepared containing:
COMPONENTS PARTS

Mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 Titanium (as titanium~ in the form 50 ppm of titanium isopropoxide organic adduct The Mack T-7 test results on the titanium compound shows a slope value of 0.026. The viscosity increase over the base line is 182% when titanium is not employed.

~ X~0~3~4 EXAMPLE V

A fully formulated lubricant composition is prepared containing:
COMPONENTS PARTS

Mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 This example utilizes copper phenate at 150 ppm of copper. A further variation is the use of manganese salicylate, substituted for the copper phenate at 450 ppm manganese.

EXAMPLE VI

A fully formulated lubricant composition is prepared containing:
COMPONENTS PARTS

mineral oil 92.45 Viscosity Improver 0.68 Basic Magnesium alkylated benzene sulfonate 0.77 Dispersant 3.48 Zinc salts of alkylated phosphorodithioic acids 1.43 Anti-wear detergent 1.11 Silicone anti-foam 0.001 Antioxidant 0.08 Vanadium at 100 ppm is substituted for the manganese compound of Example I as the neooctanoate. A further variation is utilizing equal levels of nickel, tungsten, molybdenum and chromium in place of the manganese.

Claims

1. A lubricant composition comprising an oil of lubricating viscosity, a dispersant, and a minor amount of an oil-soluble or oil-dispersible metallic compound in an amount sufficient to retard soot related viscosity rate increase of the oil when utilized in a diesel engine wherein the metallic compound contains a metal selected from the group consisting of manganese, titanium, cobalt, copper, vanadium, nickel, tungsten, molybdenum, and chromium, and mixtures thereof.

2. The lubricant composition of claim 1 wherein the oil of lubricating viscosity is present at from about 75%
to about 99.5% by weight of the composition.

3. The lubricant composition of claim 1 wherein the metallic compound is present as the metal at about 30 ppm to about 500 ppm of the composition.

4. The lubricant composition of claim 1 wherein the total base number is from about 0 to about 25.

5. The lubricant composition of claim 1 which is substantially free of lead.

6. The lubricant composition of claim 1 wherein the metallic compound is a sulfonate.

7. The lubricant composition of claim 1 wherein the metallic compound is a carboxylate.

8. The lubricant composition of claim 1 wherein the metallic compound is a phosphonate.

9. The lubricant composition of claim 1 wherein the metallic compound is a salicylate.

10. The lubricant composition of claim 1 wherein the metallic compound is a phenate.

11. The lubricant composition of claim 1 containing a viscosity improver at about 5% to about 15% by weight of the composition.

12. The lubricant composition of claim 1 wherein the metallic compound contains a member selected from the group consisting of manganese, titanium, and cobalt and mixtures thereof.

13. The lubricant composition of claim 1 wherein the metallic compound contains a member selected from the group consisting of copper and chromium and mixtures thereof.

14. The lubricant composition of claim 7 wherein the carboxylate is a fatty acid having from about 6 to about 30 carbon atoms per carboxyl group.

15. The lubricant composition of claim 12 wherein the metallic compound contains manganese.

16. The lubricant composition of claim 12 wherein the metallic compound contains titanium.

17. The lubricant composition of claim 1 wherein the dispersant is selected from the group consisting of phosphorous containing olefin polymers, amine dispersants, Mannich dispersants, and the alkali metal and alkaline earth metal salts of carboxylic acids, sulfonic acids and organic phosphorous acids.

18. The lubricant composition of claim 7 wherein the carboxylate is derived from a branched chain fatty acid.

19. The lubricant composition of claim 17 wherein the dispersant is present at about 0.05% to about 20% by weight of the composition.

20. The lubricant composition of claim 1 wherein the metallic compound is a naphthenate.

21. The lubricant composition of claim 1 wherein the metallic compound is present as the metal at about 35 ppm to about 350 ppm of the composition.

22. The lubricant composition of claim 1 also containing a zinc compound.

23. A lubricant composition comprising a major amount of an oil of lubricating viscosity and about 30 ppm to about 500 ppm as the metal of an oil-soluble or oil-dispersible metallic compound capable of retarding soot related viscosity rate increase of the oil when utilized in a diesel engine wherein the metallic compound contains a metal selected from the group consisting of manganese, titanium, cobalt, chromium, vanadium, nickel, tungsten, molybdenum, and mixtures thereof.

24. The lubricant composition of claim 23 wherein the total base number is 0 to about 25.

25. The lubricant composition of claim 23 containing a dispersant.

26. The lubricant composition of claim 23 wherein the metallic compound is a carboxylate.

27. The lubricant composition of claim 23 wherein the metallic compound is a phosphonate.

28. The lubricant composition of claim 23 wherein the metallic compound is a salicylate.

29. The lubricant composition of claim 23 wherein the metallic compound is a phenate.

30. The lubricant composition of claim 23 containing a viscosity improver at about 5% to about 15% by weight of the composition.

31. The lubricant composition of claim 23 wherein the metallic compound contains a metal selected from the group consisting of manganese, titanium, and cobalt and mixtures thereof.

32. The lubricant composition of claim 26 wherein the carboxylate is a fatty acid having about 6 to about 30 carbon atoms per carboxyl group.

33. The lubricant composition of claim 23 wherein the metallic compound is a naphthenate.

34. The lubricant composition of claim 31 wherein the metal is manganese.

35. The lubricant composition of claim 26 wherein the carboxylate is derived from a branched chain fatty acid.

36. The lubricant composition of claim 23 wherein the metallic compound is a sulfonate.

37. The lubricant composition of claim 23 wherein the metallic compound is present as the metal at about 35 ppm to about 350 ppm of the composition.

38. The lubricant composition of claim 25 wherein the dispersant is present at about 0.1% to about 15% by weight of the composition.

39. The lubricant composition of claim 23 which is substantially free of lead.

40. The lubricant composition of claim 23 also containing a zinc compound.

41. The lubricant composition of claim 25 wherein the dispersant is selected from the group consisting of phosphorous containing olefin polymers, amines dispersants, Mannich dispersants, and the alkali metal and alkaline earth metal salts of carboxylic acids, sulfonic acids and organic phosphorous acids.

42. A process for retarding soot related viscosity rate increase of a lubricant in a lubricating system prone to soot build-up comprising the steps of introducing to a lubricant a metallic compound wherein the metal is selected from the group consisting of manganese, titanium, cobalt, copper, vanadium, nickel, tungsten, chromium, and molybdenum, and mixtures thereof in an amount sufficient to retard the viscosity rate increase.

43. The process of claim 42 wherein the metallic compound contains manganese which is present as the metal at about 30 ppm to 500 ppm of the lubricant.

44. The process of claim 42 wherein the metallic compound contains manganese.

45. The process of claim 42 wherein the metallic compound contains titanium.

46. The process of claim 42 wherein the metallic compound contains cobalt.