AU604678B2 - Lubricant composition containing transition metals for viscosity control - Google Patents

Description

DECLARED AT Wickliffe, Ohio No Legalization No Corporate Seal this day of July 19 89 Signature of Declarant George R. Hill Senior Vice President To: The Commissioner of Patents.

,Af-2/U A. 4F V de a V#"'r-cJi'94e r-'-9eCU e

PC'

WORLD INTELLECTUAL PROPERTY ORGANIZATION Intonational'ureau 9 ele 7 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) Internrtional Publication Number: WO 87/ 04454 141/00, 141/12 A3 (43) International Publication Date: 30 July 1987 (30.07.87) (21) International Application Number: PCT/US87/00070 (81) Designated States: AT (European patent), AU, BE (European patent), BR, CH (European patent), DE (Eu- (22) International Filing Date: 12 January 1987 (12.01.87) ropean patent), DK, FI, FR (European patent), GB (European patent), IT (European patent), JP, LU (European patent), NL (European patent), NO, SE (31) Priority Application Number: 820,860 (European patent).

(32) Priority Date: 21 January 1986 (21.01.86) Published (33) Priority Country: US With international search report.

Before the expiration of the time limit for amending the claims and to be republished in the event of the receipt of (71) Applicant: THE LUBRIZOL CORPORATION [US/ amendments.

US]; 29400 Lakeland Blvd., Wickliffe, OH 44092 (88) Date of publication of the international search report: (72) Inventor: RIPPLE, David, Eugene 7657 Markell 11 September 1987 (11.09.87) Road, Kirtland, OH 44094 (US).

(74) Agents: COLLINS, Forrest, L. et al.; The Lubrizol Corporation, 29400 Lakeland Blvd., Wickliffe, OH 44092

(US).

(54) Title: LUBRICANT COMPOSITION CONTAINING TRANSITION METALS FOR VISCOSITY CONTROL (57) Abstract 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.

L

i WO 87/04454 PCT/US87/00070 1 LUBRICANT COMPOSITION CONTAINING TRANSITION METALS FOR VISCOSITY

CONTROL

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 thickens 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 t6 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 Engine 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 dj L WO 87/04454 PCT/US87/00070 -2produced 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.

It has been suggested in the application of Koch et al filed September 24, 1985, Serial No. 779,725 (Attorney's Docket No. L-2226B), that various metal complexes of Mannich bases of transition metals may be utilized in fuels. Koch et al also suggest that a Schiff base may be incorporated into their compositions. Dorer et al in pending application Serial No. 539,350, filed October 5, 1983 (Attorney's Docket No. L-2161B) suggests that mixtures of manganese containing salts and hydrocarbon-soluble copper containing salts may be utilized as fuel additives to reduce the ignition temperature of exhaust particulates from diesel engines.

Diesel lubricants containing alkali metal salts as additives to minimize undesirable viscosity increases in diesel engines are described in United States Serial No.

777,975, filed by Ripple (Attorney's Docket No. L-2238R) on September 19, 1985. The Ripple application further describes dispersants which are useful in diesel crankcase lubricants. Transition metal containing hydrocarbon soluble compositions containing ashless dispersants and phenolic anti-oxidants are disclosed in Tupa, United States Serial No. 606,442, filed August 30, 1984 (Attorney's docket no. 2176B).

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 SUBSTITUTE SHEET r I: i WO 87/04454 PCT/US87/00070 3 the 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 thcusand with coal. The materials suggested by Yan include a member selected 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 expected to be found in a used crankcase oil from a diesel engine.

Various transition metals as oxidation 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 ii L Z WO 87/04454 PCT/US87/00070 4 viscosity increase and the viscosity rate increase (acceleration). The compositions of the present invention are particularly effective in diesel oils which are subject 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. To the extent that the references cited in this application are applicable to the present invention, they are herein incorporated by reference.

SUMMARY OF THE INVENTION A feature 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 therof.

A futher embodiment of the invention is a lubricant composition comprising a major amount of an oil nf 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.

The invention also describes a method of 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 i viscosity increase and the viscosity rate increase (acceleration). The compositions of the present invention are particularly effective in diesel oils which are subject 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. To the extent that the references cited in this application are applicable to the present invention, they are herein incorporated by reference.

"l SUMMARY OF THE INVENTION According to a first embodiment of this invention there is provided 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 and copper, and mixtures thereof in an amount sufficient to retard the ,riscosity rate increase.

According to a second embodiment of this invention there is provided a method 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 the lubricant a metallic compound selected from the group consisting of manganese, titanium, cobalt, and copper, and mixtures thereof in an amount sufficient to retard the viscosity rate increase wherein the lubricant contains an oilsoluble or oil-dispersible basic alkali metal or alkaline earth metal salt.

/L T DETAILED DESCRIPTION OF THE INVENTION Basically, in this invention a composition comprising a polyvalent metal compound and a diesel lubricating oil may be employed. The metallic compound includes both organic and inorganic forms of manganese, copper, titanium, cobalt, 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, 10: and carbonates. Organic and inorganic metal compounds are useful in mixtures .4oo within the lubricant composition. 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, S preferably less than 0.08 during the 100 to 150 hour interval.

15 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 than 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, the carboxylates, sulfonic acids, particularly those containing an aromatic ring structure benzene ring) substituted with one or more alkyl groups of 4 to about 30 carbon atoms, a sulfonate, and phosphorus acids, U-6-1 iJ

-IL_-

M

f

L

WO 87/04454 PCT/US87/00070 7 compounds useful as dispersants. Typical high molecular weight acids are those made by reacting a poly(isobutene) fraction 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.

USed rn The useful metallic compounds e4 this invention can also be made from carboxylic acids and even acidic hydroxy compounds 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 sulfonic 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 37cC to about 200 seconds at 99°C; petrolatum sulfonic acids; mono- and polywax substituted sulfonic and polysulfonic acids of, benzene, naphthalene, phenol, diphenyl ether, nap"thalene disulfide, diphenyl amine, thiophene, alpha-cnloronaphthalene, 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 S/ principally mixtures of mono- and di-dodecylbenzenes.

qC'N T O s\ 1 1 WO 87/04454 PCT/US87/00070 8 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., cycloaliphetic 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 In aI eIbodimtf- a( The-usefualsalts 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 7 4F NT t 01 t J WO 87/04454 PCT/US87/00070 9 4,191,658 to Jahnke issued March 4, 1980, which discloses phosphorus acid salts of the formula

X

3

R(X

a P-X4M R2 X2 b wherein M is the aforementioned metal of the metallic 1 2 compound or mixtures thereof; each R and R is a 1 2 3 4 hydrocarbon radica3; each of X X X and X 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 oxide, cupric hydroxide and cupric carbonate.

A particularly preferred method of obtaining the metallic compound 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 el. I E rve t icula~, thiO s h inenti relatesto manganese salts of organic acids which are hydrocarbon-soluble.

_i i WO 87/04454 PCT/US87/00070 Highly overbased manganese metal organic compositions comprising a manganese oxide-hydroxide-carboxylate complex wherein 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,-e- 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 used 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 -einvention -l contemplates the use of other additives. Such additives include, for example, L 11 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 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 50 0 C 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 dodecylamir..

A

particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic i lunrcant in a lUDncatng system prone to soot oua-up comprising tne steps or introducing to the lubricant a metallic compound selected. from the group consisting of manganese, titanium, cobalt, and copper, and xiures thereof in an /2 r j r i WO 87/04454 PCT/US87/00070 alkaline earth metal neutralizing agent and at least one alcohol promoter, and carbonating the mixture at an elevated temperature such as 60-200 0

C.

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, ad ay of them are suitable for use in the lubricant compositionsA]& this invention. The following are illustrative: 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. Examples of these "carboxylic dispersants" are described in British Patent 1,306,529 and in many U.S. patents including the following: PATENT INVENTOR ISSUE DATE 3,163,603 3,184,474 3,215,707 3,219,666 3,271,310 3,272,746 3,281,357 3,306,908 3,311,558 3,316,177 3,340,281 3,341,542 3,346,493 Le Suer Rense Norman et al Le Suer Le Suer et al Vogel Le Suer Prizer et al Dorer Brannen Le Suer et al Le Suer December 29, 1964 November 2, 1965 November 23, 1965 September 6, 1966 September 13, 1966 October 25, 1966 February 28, 1967 March 28, 1967 April 25, 1967 September 5, 1967 September 12, 1967 October 10, 1967

V

L'i7 WO 87/04454 PCT/US87/00070 3,351,552 3,381,022 3,399,141 3,415,750 3,433,744 3,444,170 3,449,048 3,448,049 3,451,933 3,454,607 3,467,668 3,501,405 3,522,179 3,541,012 3,542,680 3,543,678 3,567,637 3,574,101 3,576,743 3,630,904 3,632,510 3,632,511 3,697,428 3,725,441 4,234,435 Re 26,433 Le Suer Le Suer Clemens Anzenberger Le Suer Norman et al Le Suer Preuss et al Leister Le Suer Gruber et al Willette Le Suer Stuebe Le Suer November 7, 1967 April 30, 1968 August 27, 1968 December 10, 1968 March 18, 1969 May 13, 1969 June 3, 1969 June 3, 1969 June 24, 1969 July 8, 1969 September 16, 1969 March 17, 1970 July 28, 1970 November 17, 1970 November 24, 1970 March 2, 1971 April 6, 1971 April 27, 1971 December 28, 1971 January 4, 1972 January 4, 1972 April 3, 1973 November 18, 1980 August 6, 1968 Sabol Murphy Widmer et Musser et Le Suer Chien-Wei Murphy Meinhardt Le Suer al al Liao 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 3,565,804 vander Voort et al July 8, 1969 Honnen et al February 23, 1971

I

WO 87/04454 PCT/US87/00070 14 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. patc

PATENT

2,459,112 2,962,442 2,984,550 3,036,003 3,166,516 3,236,770 3,355,270 3,368,972 3,413,347 3,442,808 3,448,047 3,454,497 3,459,661 3,461,172 3,493,520 3,539,633 3,558,743 3,586,629 3.591,598 3,600,372 3,634,515 3,649,229 3,697,574 3,725,277 3,725,480 3,726,882 3,980,569 Products carboxylic, amine ents are illustrative:

INVENTOR

Oberright Andress Chamot Verdol Matson Amick Otto Worrel Traise Traise Wittner Schlobohm Verdol et al Piasek et al Verdol et al Otto et al Traise et al Udelhofen et al Piasek et al Piasek et al Worrel Traise et al Traise et al Pindar et al obtained by ISSUE DATE January 11, 1949 November 29, 1960 May 16, 1961 May 27, 1962 February 22, 1966 November 28, 1967 February 13, 1968 November 26, 1968 May 6, 1969 June 3, 1969 July 8, 1969 August 5, 1969 February 3, 1970 November 10, 1970 January 26, 1971 June 22, 1971 July 6, 1971 August 17, 1971 January 11, 1972 October 10, 1972 April 3, 1973 April 3, 1973 April 10, 1973 September 14, 1976 post-treating the or Mannich dispersants with such c i -I lubricants meeting, Tulsa, Oklahoma on October 23, 1985.

The Covitch et al paper teaches that soot, which is I i i ;i 1 ii WO 87/04454 PCT/US87/00070 reagents as urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, phosphorus compounds or the like. Exemplary materials of this kind are

PATENT

described in the following U.S. patents: INVENTOR ISSUE DATE 3,036,003 3,087,936 3,200,107 3,216,936 3,254,025 3,256,185 3,278,550 3,280,234 3,281,428 3,282,955 3,312,619 3,366,569 3,367,943 3,373,111 3,403,102 3,442,808 3,455,831 3,455,832 3,493,520 3,502,677 3,513,093 3,533,945 3,539,633 3,573,010 3,579,450 3,591,598 3,600,372 3,639,242 3,649,229 Verdol Le Suer Le Suer Le Suer Le Suer Le Suer Norman et al Le Suer Le Suer Dale Norman et al Le Suer et al Le Suer Traise et al Verdol et al Le Suer Le Suer Vogel Piasek et al Mehmedbasich Le Suer Traise Le Suer May 22, 1962 April 30, 1963 August 10, 1965 November 9, 1965 May 31, 1966 June 14, 1966 October 11, 1966 October 25, 1966 November 1, 1966 April 4, 1967 January 30, 1968 March 12, 1968 September 24, 1968 May 6, 1969 February 3, 1970 March 24, 1970 May 19, 1970 October 13, 1970 November 10, 1970 March 30, 1971 May 18, 1971 July 6, 1971 February 1, 1972 L i _I patent is apparently to rapidly increase the oxidation of SUBSTITUTE

SHEET

WO 87/04454 PCT/US87/00070 16 3,649,659 Otto et al March 14, 1972 3,658,836 Vineyard April 25, 1972 3,697,574 Piasek et al October 10, 1972 3,702,757 3,703,536 3,704,308 3,708,422 Swanson January 2, 1973 Interpolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight olefins with monomers containing polar substituents, 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 Fields 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 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 M O__ De UTiIiLZt:u -L11 j.j.J.LA ii-i composition to substantially reduce the soot related 17 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 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 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 polybutylenes, polypyropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, etc.) poly(l-hexenes), poly(l-octenes), poly(l-decenes), etc. and mixtures thereof; alkylbenzenes dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes, etc.); polyphenyls 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 -k 10 te pepartio ofthe iesl lbricntsof he ivenion comprising the steps of introducing to a lubricant a metallic compound wherein the metal is selected from the WO 87/04454 PCT/US87/00070 18 by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers 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 C 3

-C

8 fatty acid esters, or the C 13 oxo acid diester of tetraethylene glycol.

Another suitable class of snythetic lubricating oils that can be used comprises the esters of dicarboxylic acids phthalic acid, succinic acid, 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 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 C to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.

Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants I 1 WO 87/04454 PCT/US87/00070 19 tetraethyl silicate, tetraisopropyi 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 phosphoruscontaining acids 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 oils.

P-1 I I I I I i I 1 I

'I

WO 87/04454 PCT/US87/00070 1 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 crankcase in the presence of a dilrent 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.

4 (bottoms) sulfonic acids. Dodecylbenzene (bottoms) are principally mixtures of mono- and di-dodecylbenzenes.

SNT

I

WO 87/04454 PCT/US87/00070 21 The total base number of the diesel lubricant is typically between 0 and 25, preferably between 1 and 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 rpay be at least 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

.I

WO 87/04454 PCT/US87/00070 22 skilled 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 exempliff d by chlorinated aliphatic hydrocarbons such as chlorinated was; organic sulfides and polysulfides such as benzyl disulfide, bis(chlorobenzyl)disulfide, dibutil 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 phosphit!, 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 dithiocarbamiate; Group II metal phosphorodithioates such as zinc dicyclohexylphosphorodithioate, zinc dioctylphosphorodithioate, 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 alcohol.

Many of the above-mentioned auxiliary extreme pressure agents and corrosion-oxidation inhibitors also serve as antiwear agents. Zinc dialkylphosphorodithioate compounds are a well known example.

m th -articlar -this inlention- relates to manganese salts of organic acids which are hydrocarbon-soluble.

I i I 13 e i SWO 87/04454 PCT/US87/00070 23 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 polymethacrylates; 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 Co:poration, 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 E. pinven ti on-a contemplates the use of other Sadditives. Such additives include, for example, ii i 1 i WO 87/04454 PCT/US87/00070 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 ethylenepropylene copolymers; styrene butadiene copolymers and homopolymers 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.

i particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic I I i- i WO 87/04454 PCTUS87/00070 EXAMPLE I A fully formulated lubricant composition is containing:

COMPONENTS

Mineral oil Viscosity Improver Basic Magnesium alkylated benzene sulfonate Dispersant Zinc salts of alkylated phosphorodithioic acids Anti-wear detergent Silicone anti-foam Antioxidant Manganese as its sulfonate from dialkylated benzene having an average alkyl benzene molecular weight between 300 and 380 reported as manganese metal prepared

PARTS

92.45 0.68 0.77 3.48 1.43 1.11 0.001 0.08 50 ppm 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.

i- 3,346,493 Le Suer October 10, 1967 J/ RA( i WO 87/04454 PCT/US87/00070 26 EXAMPLE II A fully formulated lubricant composition is prepared cont-inj.ng~: 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.

:1 3,565,804 Honnen et al February 23, 1971 WO 87/04454 PCT/US87/00070 27 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 value 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.

Products carboxylic, amine obtained by post-treating the or Mannich dispersants with such ;r I I I WO 87/04454 PCT/US87/00070 EXAMPLE IV A fully formulated diesel lubricant composition is prepared containing: COMPONENTS PARTS 92.45 Mineral oil Viscosity Improver Basic Magnesium alkylated benzene sulfonate Dispersant Zinc salts of alkylated phosphorodithioic acids 0.68 0.77 3.48 Anti-wear detergent Silicone anti-foam Antioxidant 1.43 1.11 0.001 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.

WO 87/04454 PCT/US87/00070 29 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.

Tp composition contains a "major amount" of a specific

LL

o~k~ i b- WO 87/04454 PCT/US87/00070 EXAMPLE VI A fully formulated lubricant composition is containing:

COMPONENTS

prepared

PARTS

mineral oil Viscosity Improver Basic Magnesium alkylated benzene sulfonate Dispersant Zinc salts of alkylated phosphorodithioic acids Anti-wear detergent 92.45 0.68 0.77 3.48 1.43 1.11 0.001 0.08 Silicone anti-foam Antioxidant 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 (15)

1. 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 and copper, and mixtures thereof in an amount sufficient to retard the viscosity rate increase.

2. The process of claim 1, wherein the metallic compound contains manganese which is present as the metal at 30 ppm to 500 ppm of the lubricant.

3. The process of claim 1, wherein the metallic compound contains .0o: manganese.

4. The process of claim 1, wherein the metallic compound contains titanium.

5. The process of claim 1, wherein the metallic compound contains cobalt. .9o.

6. The process of claim 1, wherein the metallic compound contains copper.

7. A process for retarding soot related viscosity rate increase of a lubricant in a lubricating system prone to soot build-up which process is substantially as hereindescribed with reference to any one of the Examples.

8. The product whenever prepared by the process of any one of claims 1 to 7.

9. A method 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 the lubricant a metallic compound selected from the group consisting of manganese, titanium, cobalt, and copper, and mixtures thereof in an amount sufficient to retard the viscosity rate increase wherein the lubricant contains an oil-soluble or oil-dispersible basic alkali metal or alkaline earth metal salt. IS Ui V, C/T 31 various metals used nerein are rouna In petroleum aerivea oils. 4 The method of claim 9, wherein the metallic compound is present as the metal at 30 ppm to 500 ppm of the lubricant.

11. The method of claim 9, wherein the metallic compound contains manganese.

12. The method of claim 9, wherein the metallic compound contains titanium.

13. The method of claim 9, wherein the metallic compound contains cobalt. So* 14. The method of claim 9, wherein the metallic compound contains copper. S.10: 15. The method of any one of claims 9 to 14, wherein the lubricating system prone to soot build-up is a diesel engine.

16. The method of any one of claims 7 to 15, substantially as S hereindescribed with reference to any one of the Examples. DATED this 6 day of July 1990. THE LUBRIZOL CORPORATION By Their Patent Attorneys: CALLINAN LAWRIE ir -32- L "I i i INTERNATIONAL SEARCH REPORT International Application No PCT/US 87/00070 I. CLASSIFICATION OF SUBJECT MATTER (if several classification symbols apply, Indicate all) According to international Patent Classification (IPC) or to both National Classification and IPC 4 IPC C 10 M 141/00; C 10 M 141/12 II. FIELDS SEARCHED Minimum Documentation Searched Classificalion System Classification Symbol! 4 IPC C 10 M Documentation Searched other than Minimum Documentation to the Extent that such Documents are Included In the Fields Searched Ill, DOCUMENTS CONSIDERED TO BE RELEVANT' Category Citation ol Document, with indication, where aporopriate, of the relevant passages 12 Relevant to Claim No. P,X,L Chemical Patents Index, Basic Abstracts Journals, Section Ch, week 8617, see 1-46 abstract no. 86-106784/17, Derwent Publictions Ltd, (London GB), JP, A, 6164792 (LUBRIZOL CORP.) 3 April 1986, AU, A, 8546694 (LUBRIZOL CORP.) 6 March 1986 cited in the application X US, A, 4122033 BLACK) 24 October 1978 see abstract; column 2, lines 36-54, 23,26,31- and line 60 column 3, line 13; 34 column 3, line 34 column 4, line 19; column 5, line 60 column 6, line 20; column 6, lines 32-42; column 7, line 42 column 9, line 12; column 9, lines 21-32; column lines 14-21; column 11, lines

31-40, 53-65; column 12, lines 3-6; column 15, lines 24-25; claims 4-11, 13,15,22,33, 38-40 Special categories of cited documents: to later document published after the International filing date document defining the general state of the art which is not or priority date and not in conflict with the aplication but considered to be of particular relevance cited to understand the principle or theory underlying the invention earlier document but published on or after the international X" document of particular relevance; the claimed invention filing date cannot be considered novel or cannot be considered to document which may throw doubts on priority claim(s) or involve an inventive step which is cited to establish the publication date of another document of partcular relevance; the claimed invention citation or other specal reason (s specied) document Df particular relevance; the claimad "nvan on cannot be considered to Involve an inventive stelap when the document referring to an nral disclosure, use, exhibition or document is combined with one or more other such docu- other means ments, such combination being obvious to a person skilled document published prior to the international filing date but In the art. later than the priority date claimed document member of the same patent family IV. CERTIFICATION Date of the Actual Completion of the International Search Date of Mailing of this International Search Report 22nd July 1987 0 AUG SJ international Searching Authority Signature of Authorized Offct I EUROPEAN PATENT OFFICE M. VAN MOL Form PCT/ISA/210 (second sheet) (January 1985) 161 -1 os w- serve as antiwear agents. Zinc dialkylphosphorodithioate compounds are a well known example. 4 r 1 -2- Interrational Application No. PCT/US 87/00070 Ill. DOCUMENTS CONSIDERED TO BE RELEVANT (CONTINUED FROM THE SECOND SHEET) Category Citation of Document, with indicaton, where appropriate, of the relevant passages Relevant to Clam No Y cited in the application X EP, A, 0024146 (EXXON RESEARCH AND ENGINEERING COMPANY) 25 February 1981 see page 1, line 1 page 2, line 4; page 2, lines 13-16, 25,26; page 4, lines 1-4, 11-15; page 5, lines 1-5, 16-19; page 6, line 13 page 8, line page 8, lines 13-18; page 10, lines 5-22, 26; page 11, lines 12-18; page 12, lines 11-15; page 13, line 1 page 22, line 24; page 34, lines 1-6; claims 1-5, 11-14 Y cited in the application X US, B, 29661 HENDRICKSON) 6 June 1978 see column 7, lines 6-58; column 9, lines 31-35 cited in the application US, A, 3801507 X US, A, 3652616 WATSON) 28 March 1972 see abstract; column 2, line 54-57; column 3, lines 41-50; column 6, lines 66-71 Y cited in the application X US, A, 2976238 ELLIOT) 21 March 1961 see column 2, lines 26-56; column 4, lines 28-31; column 5, lines 11-31 Y X GB, A, 997335 (CONTINENTAL OIL CO.) 7 July 1965 see page 1, lines 23-49; page 4, lines 55-62; page 5 1-22,24,25, 27-30,35-46 1-11,13,14, 17-30,32,33,

35-43 12,15,16, 31,34,44-46 1-3,7,12,13, S15,18,20,23, 25,34,44 1,4,12,16, 17,31 2-11,13-15, 17-30,32-46 8,27 1-7,9-26, 28-46 1,13,23,31, 46 2-12,14-22, 24-30,32-45 Form PCT ISA 210 (extra sheet) (January 1985) t r viscosity improvers function to maintain more or less I I I p lik C ANNEX TO THE INTERNATIONAL SEARCH REPORT ON INTERNATIONAL APPLICATION NO. PCT/US 87/00070 (SA 15900) This Annex lists the patent family members relating to the patent documents cited in the above-mentioned international search report. The members are as contained in the European Patent Office EDP file on 31/07/87 The European Patent Office is in no way liable for these Particulars which are merely given for the purpose of information. Patent document cited in search report Publication date Patent family member(s) US-A- 4122033 24/10/78 FR-A,B DE-A- JP-A- CA-A- GB-A- CH-A- EP-A- 0024146 25/02/81 GB-A- JP-A- AU-A- AU-B- CA-A- 2372222 2731217 53067686 1089214 1599287 634344 2056482 56053189 6136780 537461 1170247 Publication date 23/06/78 01/06/78 16/06/78 11/11/80 30/09/81 31/01/83 18/03/81 12/05/81 19/02/81 28/06/84 03/07/84 US-D- 29661 None US-A- 3652616 28/03/72 None US-A- 2976238 NL-C- 103587 GB-A- 997335 NL-A- 281035 US-A- 3141745 For more details about this annex see Official Journal of the European Patent Office, No. 12/82