US3053766A - High detergency automotive engine lubricant - Google Patents

Description

Se t. 11, 1962 M. w. MUNSELL ETAI. 3,053,766

HIGH DETERGENCY AUTOMOTIVE ENGINE LUBRICANT Filed July 25, 1958 2 Sheets-Sheet 1 FIGURE'I COMPARISON OF SLUDGE DEMERITS 2o FORMULATION 3 SLUDGE DEMERIT FORMULATION 2 FORMULATION#4\ O 44 88 I32 I76 220 264 RUNNING HOURS Monroe W. Munsell Stephen L. Wyfhe Inventors y I 6?. M Attorney Sept. 11, .1962

Filed July 25, 1958 M. w. MUNSELL EI'AL 3,053,766

HIGH DETERGENCY AUTOMOTIVE ENGINE LUBRICANT 2 Sheets-Sheet 2 FORMULATIONHS OIL WITHOUT DETERGEN FORMULATION? l l l t l o no 220 330 440 550 FORMULATION "*6 OH. WITHOUT DETERGENTS FORMULATION#'I ENGINE TEST HOURS F lGURE-JI Monroe W. Munsell Stephen L. Wythe Inventors By fa. M tt r y United States Patent Ofiiice 3,053,766 Patented Sept. 11, 1962 3,053,766 HIGH DETERGENCY AUTOMOTIVE ENGTNE LUBRICANT Monroe W. Munsell, Piainfield, and Stephen L. Wythe,

West'ficld, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware Filed July 25, 1958, Ser. No. 750,927 1 Claim. (Ci. 25232.7)

This invention relates to improved internal combustion engine lubricants having excellent sludge inhibiting and detergent properties. It is more particularly concerned with an additive system for mineral lubricating oil compositions. A surprisingly effective combination of two additives has been found. One is a neutralized phosphorus and sulfur-containing detergent inhibitor, and the other is a multi-functional copolymer having dispersancy properties.

Many lubricating formulations marketed today are based on the use of a base oil modified by specific additives that impart certain desired properties, such as oxidation resistance, high viscosity index, detergency, low pourpoint, anti-wear, anti-rust and color. Many quite interesting additive types have been created in response to this need. Recently, multi-functional additives or additive systems that improve two or more properties of the base lubricant have been the object of extensive research.

In developing and using lubricant additives to satisfy a specific need, the additive must not only satisfy the need but also must not adversely affect other properties of the lubricant. For example, a problem existing today has been created by the use of certain zinc and phosphoruscontaining additives to combat the extreme valve train wear that occurs in certain makes of automobiles. While a few weight percent of these phosphorus materials will greatly alleviate the valve train wear problem in a particular automobile, it has been found that the additives may severely shorten exhaust valve life in other makes of automobiles.

The present invention proposes the use of two select additives in motor oils and similar compositions, in combination, to impart a surprising high degree of detergency. Such oil formulations admirably meet the exacting requirements imposed by todays high compression automotive engines. This combination of additives has been found to be fully compatible with other types of additives that must be added to the oil formulation, and does not adversely affect other desirable performance characteristics of the lubricant.

This invention will become clear from the following description with reference to the specific examples of preferred compositions, and to the attached drawings wherein:

FIGURE I is a graphical illustration of the performance of one type of additive combination of this invention relative to the performance of oils containing each additive alone; and

FIGURE II is another graphical illustration comparing another type of additive combination of this invention to prior art compositions.

In brief compass, this invention proposes an engine lubricant comprising a major proportion of a mineral lubricating oil and in the range of 0.1 to 10.0 weight percent each of a combination of two additives. The total amount of the two additives used is usually in the range of 1.0 to 20.0 weight percent.

One of the additives is a neutralized phosphosulfurized hydrocarbon. The method of neutralizing the phosphosulfurized hydrocarbon is important because improperly neutralized materials, when combined with the multifunctional surface active polymer, may not give the results desired.

The neutralized phosphosulfurized hydrocarbon is formed by reacting an oil-soluble, normally odoriferous, phosphosulfurized hydrocarbon, preferably an olefin polymer, with a stabilizing amount of an oil-soluble, high alkalinity, neutralizing agent selected from the group consisting of metal alkyl phenates, alkyl phenate sulfides and sulfonates. The neutralized phosphosulfurized hydrocarbon has a sulfur content in the range of 3 to 8 weight percent, a phosphorus content in the range of 0.5 to 4.5 weight percent, and the mole ratio of metal to phosphorus is in the range of 1.0 to 5.0, preferably 1.5 to 3.0. Oil solutions of this additive are clear and free from obnoxious odors.

The other of the additives is a multi-functional copolymer having a sludge dispersing property. It has a molecular weight in the range of 5,000 to 200,000. The dispersant nature of the polymer is conveniently characterized by the sludge dispersancy test. The dispersant na-* ture of the preferred copolymer used in this invention is brought about by the use of a nitrogen-containing monomer to form the copolymer. Preferably, the copolymer contains in the range of 0.1 to 3.0 weight percent combined nitrogen. For example, the polymer is formed by copolymerizing in the range of 0.5 to 25.0, preferably 1 to 10, weight percent of an N-vinylbutyrolactam with an alpha, beta unsaturated ester or diester such as dilauryl fumarate. A third monomer, e.g., an unsaturated ester such as vinyl acetate, can also be copolymerized with the N-vinyl butyrolactam and alpha, beta unsaturated ester, if desired.

The combination of additives according to this invention has been found to give excellent performance in high compression engines. It results in an exceptionally clean engine, even after several hundred hours of use. This new combination of additives greatly inhibits the formation of sludge and, further, very effectively suspends those incipient sludge particles that may form. The use of this combination of additives, therefore, effectively prevents the fouling of engine parts by sludge deposition during operation. The combination of additives is particularly eifective in meeting the severe demands imposed by the low temperature stop-and-go service occasioned by todays high compression, high horsepower automotive engines.

Zinc dialkyl dithiophosphates have been widely used to impart, besides oxidation resistance, extreme pressure properties to lubricants. With other conventional additives, it has been found that the phosphates must be used in an amount that can cause extreme exhaust valve burn-' ing, particularly in the types of cars having light high speed engines. The new multi-functional combination of additives of this invention has been found to permit the use of substantially lower phosphorus contents in oil formulations, such that the exhaust valve burning prob lem is made negligible or removed while still permitting the lubricant to give satisfactory performance in automobiles sensitive to valve train wear.

The neutralized phosphosulfurized hydrocarbon compo nent of the additive system of this inventionis more fully described in co-pending application Serial No. 716,394, Improved Phosphosulfurized Detergent-Inhibitor Additive, filed February 20, 1958, and now US. Patent No. 2,969,324. Suitable hydrocarbon raw materials for forming the phosphosulfurized component have viscosities above 100 SSU at 210 F. and can be solids at this temperature. They can have boiling points above 400 F. at 10 mm. Hg abs. ranging upward to their decomposition temperature at this pressure. Hydrocarbons having a viscosity in the range of 1000 to 50,000 SSU at 210 F. are particularly preferred. Preferably, materials that are predominantly parafiinic are used, i.e., they contain over of alkyl hydrocarbons, and less than 5% of the carbon atoms are in aromatic rings. While many hydrocarbon sources can be used, preferred sources are heavy petroleum fractions including extracted residua and the polyolefins, e.g., polybutene polymers, especially polyisobutylene.

When petroleum fractions are used, they preferably meet the following inspections:

Viscosity, SSU at 210 F 140-250 Viscosity index 70-110 Metals content, wt. percent 0.2 API gravity, 20-27 The polybutenes used should meet the following inspections:

Viscosity, SSU at 210 F moo-50,000 Flash, F 300 While the broad range above can be used, the polybutenes preferably have a molecular weight distribution such that 80 wt. percent of the material has a molecular weight in the narrower range of 700 to 100,000.

Phosphorus pentasulfide is used to form the phosphosulfurized hydrocarbon. While not critical, it should meet the following inspections:

Melting point, F 270-280 Phosphorus, wt. percent 27.5-29.0 Sulfur, wt. percent 71.0-73.0

The oil-soluble, high alkalinity, metal-containing, or-

ganic compounds used to stabilize or neutralize the phosphosulfurized hydrocarbons are, preferably, those known to the prior art. While several heavy di-valent metals such as zinc and magnesium are useful, the metal component is preferably calcium and/ or barium. It is preferred for the purpose of this invention to use calcium or barium alkyl phenates, alkyl phenate sulfides, sulfonates, or mixtures thereof, although equivalent calcium or barium compounds can be used.

Suitable metal alkyl phenols useful in this invention are known to the art, e.g., see US. 2,197,833. The alkyl phenols or equivalent alkylated aryl hydroxy compounds used contain one or more alkyl groups, each of which can have in the range of 1 to 30, preferably 8 to 20 carbon atoms per alkyl radical. The alkyl phenols can contain more than one ring structure, and more than one hydroxy group, although alkylated monohydroxy benzenes are preferred. The total molecular weight of the alkyl phenols used is in the range of 200 to 700. The alkyl phenols can be synthesized by simple alkylation of cresol or naphthol with olefins. A suitable product can be prepared, for example, by alkylating phenol with polymeric materials obtained for example by the acid catalyzed polymerization of propylene. These polymeric materials consist essentially of a mixture of C to C olefins, and give alkylated phenols having branched chain alkyl groups averaging 9 to 14 carbon atoms.

The alkyl phenol sulfides used are the thioethers and polysulfides of the above alkyl phenols. The sulfides comprise two or more of the alkyl phenol groups joined by one or more divalent sulfur atoms, e.g., di(2,4-ditertiary amyl phenol) monosulfide. Preferably the alkyl phenol sulfides used contain in the range of 2.5 to 4.0 weight percent sulfur as a 30 to 60 vol. percent concentrate in oil. Suitable alkyl phenol sulfides are known to the art, e.g., see U.S 2,362,289 and 2,461,335.

The alkyl phenols can be converted to phenol sulfides, for example, by reaction with sulfur dichloride to produce essentially phenol monosulfides having thioether linkages. Sulfur monochloride can be used to produce essentially alkyl phenol disulfides.

The sulfonates used are also well known in the art. The sulfonic acids can be obtained through the sulfonation of either synthetic or natural hydrocarbons. The preferred sulfonic acids have molecular weights in the range of 300 to 700 (as the sodium soap). The synthetic acids preferably have narrower molecular weights in the range of; 400 to 600. The acids can contain more than one sulfonyl group in the molecule. Suitable sulfonic acids are produced by sulfonating alkyl aromatic hydrocarbons such as didodecyl benzene. They can also be obtained by treatment of lubricating oil base stocks with concentrated or fuming sulfuric acid in a conventional manner to produce oil-soluble mahogany acids.

The alkyl phenols, the alkyl phenol sulfides, and the sulfonic acids are neutralized with an excess, usually at least 5 percent excess, of the calcium or barium base or mixtures thereof to obtain the desired high alkalinity materials. The sulfonates can, however, be first neutralized with a base of another metal, especially the alkali metals, and the desired alkaline earth material can then be obtained from these salts by reaction with the calcium or barium basic materials.

In forming the high alkalinity materials, according to one embodiment of this invention, mixtures of the alkyl phenols, alkyl phenol sulfides, sulfonic acids or their alkali metal salts are co-neutralized to obtain unusually high alkalinity complexes. Thus a mixture of phcnate sulfides and sulfonates can be obtained by blending a neutral sulfonate, e.g., sodium sulfonate, with an alkyl phenol and treating the blend with an excess of the metal neutralizing agent, e.g., barium oxide. Preferably, the neutralization of the phenols or sulfonic acids is carried out in the presence of an oil diluent.

To obtain the desired high alkalinity product, particularly in the case of the phenates, it is desirable to use during neutralization such aids as CO; and water treatment. The amount of metal retained by the product is higher and the product is usually more stable.

The formation of high alkalinity alkyl phenates, alkyl phenate sulfides, and sulfonates of the requisite oil solubility and basicity as above described is well known to the art and need not be further described.

It is important in this invention to use the proper amount of the oil-soluble, high alkalinity, metal-containing, organic compound to stabilize the phosphosulfurized hydrocarbon. To assure proper stabilization, the weight of the high alkalinity, metal-containing, organic material -times its alkaline neutralization number to a pH of 4 should exceed the weight of the phosphosulfurized hydrocarbon times its saponification number. The alkaline neutralization number is the amount of acid expressed as equivalent milligrams of potassium hydroxide which is required to react with the one gram of the high alkalinity material to produce a pH of 4. The saponification number is the milligrams of potassium hydroxide necessary to saponify one gram of the phosphosulfurized hydrocarbon. For example, if it is desired to stabilize grams of a phosphosulfurized hydrocarbon having a saponification number of 20, it is necessary to use at least 200 grams of the high alkalinity organic material when it has a neutralization number of 10.

Table I summarizes the pertinent reactant characteristics and manufacturing conditions that influence the nature of the neutralized phosphosulfurized additive used in this invention.

In forming the neutralized phosphosulfurized hydrocar-bon, the phosphorus pentasulfide is reacted with the hydrocarbon in a manner known to the art. The conditions are not too critical, although the product should meet the inspections given in the table. Preferably, the reaction mass is stripped during the reaction. The water content during or after the reaction is maintained below 0.5 weight percent to prevent undue sulfur loss.

The neutralization of the phosphosulfurized hydrocarbon is carried out at a temperature of to 600 F., preferably 280 to 450 F., and under substantially anhydrous conditions. The order of mixing the materials is not important. Preferably the reaction mixture is stripped with an inert gas during neutralization. After neutralization the product, if desired, is filtered and diluted with a suitable diluent oil.

TABLE I REACTANTS Range Preferred Weight percent S 71.0 to 73. Weight percent P. 27.5 to 29. Organic material. Nil. Melting point, F 270 to 280. Hydrocarbon: Polybutcne.

Staudinger mol. weight 700 to 100,000. Vis. at 210 F., S 1,000 to 50,000. MIig-boiling pt., F., 10 mm. Above 400.

g. Sulfonic acid (as 40-60% active ingredient concentrate in oil):

Mol. weight (as Na soap) 200 to 900 300 to 700. Weight percent 8 2 to 6. 2.5 to 4.5. Neut. number, mg. KOH/gn. 25 to 200. 50 to 80. Alkyl phenol:

M01. weight 200 to 700 300 to 500. Numberarom.rings/molecule 1 to 1. Alkyl group(s) total carbon 8 to 20.

atoms ea. Alkyl phenol sulfide (as 30-50% ac1t)ive ingredient concentrate in 01 Alkyl phenol precursor has inspections as above. Weight percent S 2 to 6. 2.5 to 4.0. Weight percent metal, as Ba 5 to 15- 10.0 to 14.0. Phosphosulfurized hydrocarbon (PSHC):

Appearance Bright, clear D0.

Watercontent,weightpercent Sapon. number, to pH of 4... Weight percent I Weight percent S Sol. of 2 weight percent in hexane at 70 F. High alkalinity organic material (as 30-60% oil concentrate):

Sol. of 2 weight percent in Do.

hexane at 70 F. Neut. number to pH of 4, 50 to 100.

mg. KOH/gr. Equig. metals/equiv. organic Greater than 2.

an s. Vis. at 210 F., SSU 200 to 400. Metals content, Weight per- 10 to 20. S cent.

tri in as:

wat n ppm Less than 100-.. Do. Percent free oxygen--. Less than 0.5.. Do.

REACTION CONDITIONS Phosphosulfurization:

Weight percent P28 on 2 to 20- 8 to 18.

hydrocarbon. Temp., F 150 to 600. 275 to 500. Time, hrs 0.5 to 15 0.5 to 10. Diluents, contaminants, etc., Less than 2 Do.

weight percent. Waterpresentaveightpercent Less than 0.5.-. Do. Neutralization of PSHO:

T 150 to 600- 280 to 450.

0.5 to 10 0.5 to 6. Water present during reac- Less than 0.5. Do.

tion, weight percent. Equiv. alkaline material/- 1 to 20 1 to 3.

equiv. of saponifiable material in PSHO. Stripping during Neutralization:

SCF inert gas, bbL/hr to 1 2 to 3 lemp., F 325 to 375 Time, hrs 3 to 6. Additive inspections:

Weight percent P 0.5 to 2.5 Weight percent combined S 2 to 6. Weight percent metal, as to 15.

barium. Gravity, API 0 to 10. Neut. number, mg. KOH/gr o. ASTM color (5 weight per- 2to 5.

cent in white oil). Vis. at 210 F., SSU 1,000 to 3,000.

The second of the additives is a inulti-functional surface active, oil-soluble copolymer having sludge dispersance properties in crankcase oils, as defined by the sludge dispersancy test. The copolymers are multi-functional in effect in that they also raise the viscosity index of an oil, and/or decrease pour point. The copolymers of this invention raise the viscosity index of a mixture of 95 vol. percent of a paraffinic solvent extracted neutral oil and 5 vol. percent of an extracted bright stock having an initial viscosity of 46 SSU at 210 F. and viscosity index of 113 by at least 20 units when 3.6 weight percent is added thereto. The copolymer is formed by reacting a polar monomer having in the range of 4 to 50 carbon atoms with at least one other monomer to achieve a long polymer chain having dependent polar or functional groups. Suitable copolymers can also be formed by graft polymerizing a polar monomer onto a completed polymer, as by irradiation. The copolymer used has an average molecular weight in the range of 5,000 to 200,000, and suspends more than 70 weight percent sludge in the sludge dispersancy test, at a 10 weight percent concentration in a standard type of lubricating test oil (a solvent extracted parafiinic oil having a viscosity at 210 F. of SSU and a viscosity index of 107).

It is preferred to use as one of the essential monomers an N-vinyl-alpha-butyrolactam in an amount inthe range of 0.5 to 25.0 weight percent based on the copolymer. Also, preferably, the other monomer copolymerized with the butyrolactam is a polymerizable, ethylenically unsat urated ester having in the range of 4 to 40 carbon atoms per molecule. The ethylenic unsaturation can be in the acid derived of alcohol-derived portion of the ester. Other polymerizable monomers can, however, be reacted With the butyrolactam. For example, terminally unsaturated olefins, vinyl aromatics such as styrene and substituted styrenes, vinyl ethers, and unsaturated carboxylic acids can beused. The basic requirement is that the monomers should be chosen and combined in such proportions as to give a final product having the requisite oil solubility and dispersancy properties.

For example, good results have been obtained by combining the neutralized phosphosulfurized hydrocarbon with a copolymer made by reacting a mixture of fumarates having an average molecular weight of 420 (tallow furnarates and C oxo fumarates), vinyl acetate (acctate/fumarate ratio=3/ l) and 3 weight percent maleic anhydride, much of the vinyl acetate being in excess and being stripped out of the copolymer at the end.

The N-vinyl-alpha-butyrolactam type of monomer used in the preferred embodiment has the formula:

H-fE-E-H R R attache wherein R is a hydrogen or a C C alkyl group and all R groups are not necessarily the same. 1 The polymerizable esters used to form the preferre copolymers are monoethylenically unsaturated, contain in the range of 4 to 40 carbon atoms, and have the formula:

wherein R is an alkyl, vinyl or substituted vinyl group having in the range of 1 to 20 carbon atoms, and R is an R group or wherein R is H or CH and R is H, R, or

being an alkyl group having in the range of l to 20 car-' bon atoms. Especially preferred acids used to form the unsaturated esters are acrylic, methacrylic, maleic and fumaric acids.

Especially preferred copolymers used as a second additive of this invention are those derived from copolymerizing 5 to 15 weight percent of N-vinyl alpha pyrrolidone with a mixture of normal C to C methyl methacry-' lates; and by reacting 4 to 15 weight percent of the pyrrolidone with 10 to 20 weight percent of vinyl acetate and 65 to 86 weight percent of di-C to C fumaratcs.

The copolymerization of two monomeric materials can be conveniently carried out by any one of several meth ods known to the art. For example, peroxide initiation can be used. Thus, the monomers can be heated with a catalyst such as benzoyl peroxide or tertiary butyl perbenzoate to a temperature in the range of 50 to 110 C. and in the presence of a diluent such as heptane, benzene, or white oil.

The additive combination of this invention is preferably used in mineral lubricating oils. The base oils used generally will have a viscosity in the range of 30 to 100 SSU at 210 F., a viscosity index in the range of 50 to 108, a pour point below 30 F., and a flash point above 300 F. The blended oils will have viscosities in the range of 45 to 150 SUS at 210 F. and 250 to 700 SUS at 100 F.

If the two additives are admixed in the proportions indicated, in the absence of any diluent oil, a non-liquid composition at room temperature usually results. For this reason, it is preferred to market the combination of additives as an oil concentrate containing in the range of 80 to 25 weight percent oil and 20 to 75 weight percent of active ingredient. The ratio by weight of the multi-functional copolymer to the neutralized phosphosulfurized hydrocarbon is in the range of 0.2 to 3.0, preferably 0.5 to 1.5, to 1. The obtainance of a marketable concentrate that imparts superior oxidation inhibition and detergency to oleaginous materials is an important feature of this invention. With phosphosulfurized materials, the odor of the products greatly affects the saleability. It is an important feature of this invention that a concentrate containing the additive of this invention is odor free. Another important feature of the concentrate, even with a relatively high concentration of active ingredients, is its physical stability. It has been found many times in the past, when attempting to prepare an oil solution containing a large amount of a phosphosulfurized hydrocarbon detergent, that the additive concentrate will turn to a gel or will precipitate gelatinous materials. The concentrate of the present invention remains essentially unchanged in viscosity and appearance without the formation of sediment even after treatment at 130 F. for six hours. It will be appreciated by those skilled in the art that an additive concentrate containing these types of materials, that is clear and stable, is one admirably suited for commercial sales.

When the two additives are blended into a lubricating oil, the viscosity of the lubricant will drift or change with time, finally in two or three days arriving at a stable viscosity. A subsidiary finding of this invention is that this drifting or stabilization of viscosity can be accelerated to a matter of a few minutes by the addition of minor amounts, 0.001 to 0.5 weight percent on total composition, of polyether alcohols, e.g., diethylene glycol ethyl ether. Thus, in blending the additives into a lubricant, the final viscosity can be quickly arrived at by the addition of these polyether alcohol viscosity stabilization agents. It is convenient to include these agents in the amounts of 0.05 to 2.0 weight percent in the concentrate blends.

An oil composition containing the additive combination of this invention can also contain other additives used to improve other properties. For example, antioxidants such as zinc dialkyl dithiophosphates, phosphosulfurized terpenes, and phenyl-alpha naphthylamines can be used. Viscosity index improvers such as the methacrylate polymers or the isobutylene polymers can be used. Extreme pressure agents such as zinc dialkyl dithiophosphates can be used. Pour point depressors such as wax-naphthalene condensates or suitable methacrylate, fumarate or maleate polymers or copolymers well known to the art can also be used.

As indicated previously, the additive combination of this invention is particularly useful in conjunction with the zinc dialkyl dithiophosphates. Preferred oil-soluble phosphates are those wherein the alkyl groups have in the range of 3 to 12 carbon atoms each. The alkyl groups can be mixed, and can be branched or straight chained. In conjunction with 1 to 10 weight percent each of the additive combinations of this invention, it has been found that only 0.2 to 1.0 weight percent of a zinc dialkyl dithiophosphate is necessary to impart the desired degree of oxidation resistance and extreme pressure properties to the finished lubricant.

While primarily intended for use in automotive engine lubricants, it will be apparent to the skilled in the art that the combination of additives of this invention is useful in other oleginous materials to impart and to improve oxidation resistance and to inhibit and suspend sludge. Thus, the neutralized phosphosulfurized hydrocarbon and the multifunctional surface active copolymer can be combined in amounts in the range of 0.001 to 2 weight percent each in heating or fuel oils, or in jet fuels to disperse sludge and haze precursors, and to impart oxidation resistance. The combination can also be used in amounts in the range of 0.01 to 10 weight percent in gear lubricants and automatic transmission fluids to inhibit varnish or sludge formation, and in synthetic ester lubricants to reduce oxidative deterioration and sludge deposits.

EXAMPLES Various oil formulations containing diiferent combinations of additives were made up and tested.

The neutralized phosphosulfurized hydrocarbon, herein called a detergent inhibitor, was made by reacting 31.6 parts (on final product) of an 1100 average molecular weight polybutene sold by the Amoco Chemical Company as Indopol H-300, with 4.74 parts of phosphorous pentasulfide for about 8.5 hours at 425 F. while blowing with nitrogen. 36 parts of the phosphosulfurized hydrocarbon so obtained were then reacted with 32 parts of a phenate sulfide and 32 parts of a sulfonate for five hours at 350 F. while blowing with nitrogen.

The phenate sulfide, a commercial lube oil additive known as Paranox 47, is an oil solution of an alkyl phenol sulfide (the alkyl group averaging 11 carbon atoms and ranging from 9 to 18 carbon atoms) neutralized with an excess of barium hydroxide and CO treated. The product contains an excess of equivalents of barium over equivalents of acidic hydroxy functions in the phenol sulfide. It has the following inspections:

Barium, wt. percent 12.012.8

Sulfur, wt. percent 2.8-3.3

Neut. number to pH of 4 73.0-93.0

The sulfonate used to neutralize the phosphosulfurized hydrocarbon is a commercially available high barium content sulfonate concentrate in oil sold by the Bryton Chemical Company. It is made by neutralizing a synthetic sulfonic acid having an average molecular weight of about 475. The sulfonate had the following inspections:

Barium, wt. percent 16.49 Sulfur, wt. percent 3.10 Neut. number to pH of 4 61.53 Initial pH 8.95

After filtering, the neutralized product had the following inspections (undiluted):

Barium, wt. percent 8.59 Phosphorus, wt. percent 1.28 Sulfur, wt. percent 4.18 Neut. number, Mg KOH/gm 6.98 Sapon. number 21.2 Vis., SUS at 210 F 2283 Flash point, F 435 ASTM color, at 5 vol. percent in white oil 4.5

This additive was used as a 75 weight percent concentrate in oil in making up the following formulations.

The multi-functional surface active polymer, herein 9 called a detergent polymer, was prepared by adding the following ingredients to a 20 gallon kettle:

Di-lauryl fumarate, wt. percent 75.2 Vinyl acetate, wt. percent 18.8 N-vinyl-alpha-pyrrolidone, wt. percent 4.0 Lauryl alcohol, wt. percent 2.0

100.0 Benzoyl peroxide (wt. percent of charge) 2.0

The ingredients were held at C. for two hours under a nitrogen blanket. The kettle temperature was then raised to C. for three hours and the temperature thereafter was steadily increased to C. The 15 materials were held at 60 C. for 16 to 24 hours until the polymer reached the desired thickness. At the end of this soaking period, the polymeric material was diluted with a paraffinic mineral oil to make a 50% concentrate.

The product was then filtered and stripped under vacuum 0 These oil formulations were tested in the following tests:

Caterpillar L-Z test.This is a test designed to evaluate the detergency of an oil in diesel engines, i.e., at relatively high temperatures. This is a standard test using a Caterpillar Single Cylinder Diesel Test Engine, CRC designation L-l-545. The fuel may contain either 0.4 or one weight percent sulfur. The test involves running a one-cylinder (5%" bore times 8" stroke) diesel engine for 120 hours or more at 1800 r.p.m. with a 20 horsepower load. The engine is then rated for cleanliness by visual inspection.

Low tempemutre sludge test.This test is designed to evaluate the performance of an oil under low temperature st0p-and-go driving conditions and in particular, its effectiveness in controlling sludge. A late-model sixcylinder Chevrolet engine, attached to a dynamometer in a test stand, is put through the following repeated cycles for a time in the range of 110-550 hours, using as the crankcase lubricant the oil under test.

Jacket Oil Exhaust water sump Intake Torque, Brak Air/fuel back Cycle Cycle R.p.m. outlet temp, air,F. lb./ft. hp. ratio pres. duration te fi pq F. mm, Hg hrs.

to remove any unreacted vinyl acetate. The final molecular weight was 35,000 (staudingery As given The various parts of the engine are rated periodically in the following tables, the weight percent of detergent polymer used includes diluent oil.

The following formulations were made up:

for sludge on a percent sludge scale, 0% being no deposits and 100% being the maximum deposits that the part is capable of holding. A rating of 20% or below TABLE II FORMULATION (voL. PERCENT) Detergent-inhibitor. 4. 0 4. 0 4. 0 6. 5 6. 5 Detergent polymer cone 10.0 10.0 9. 0 Polybutene cone 1 2. 6 Acryloid 710 5.0 Acryloid 763 4. 8 Acryloid 966 5.0 4. 0 Phenate Sulfide 5 3. 6 Sulfonate 1. 5 ZDDP 0.7 0.7 1.0 0.7 0.9 0.7 0.7 Oil-1 9 47. 7 49.1 49. 8 Oil-2 37. 6 38. 6 39. 2 Oil-3 86. 3 Oil-4 11 32. 5 Oil-5 56. 5 011-6 13 67. 7 65. 2 Oil-7 14 20. 3 23. 6

INSPECTIONS Gravity, API 29. 7 30.0 30. 5 29.6 Vis. at 100 F., SUS 440.3 357.6 377.3 393.5 359. 2 317.7 310. 9 Vis. at 210 F., SU 76. 0 68. 6 70.0 69. 6 65. 9 64. 13 63.19 i i y 138.0 140. 5 139. 4 138. 4 135. 4 140. 8 140. 5 Acid number 1. 5 1. 3 Sulfated ash 0. 73 1. 0 1.0 Barium 0. 75 0.41 0.41 Zine 0. 088 0. 075 0. 075 Phosphorus 0.091 0. 14 0. 14 Sludge dispersancy test, weight percent sludge suspended at 10 weight percent cone. in

test 0' 25 70 90 90 30 90 1 A commercially available viscosity index improver prea gravity of 295 API, an open cup flash of 435 F., a vis- 5 This is Paranox 47, the high barium alkyl phenate sulfide, previously described. %hdis is high barium synthetic sulfonate, previously descri e This is an oil solution of zinc dialkyl dithiophosphate known as Lubrizol 1060. The alkyl groups are derived from isopropanol and methyl isobutyl carbinol.

A phenol treated solvent dewaxed lubricating oil having 1 cosity of 245 SUS at F., a viscosity index of 100, and a Conradson carbon residue of 0.08.

This is a phenol treated and solvent dewaxed oil having a gravity of 33.1 API, an open cup flash of 380 F., a pour point of 20 F., a viscosity of -115 SUS at 100 F., and a. viscosity index of 100.

This is a phenol treated and solvent dewaxed lubricating oil having a gravity of 315 API, an open on flash of 410 F., a pour point of 15 F., a viscosity of 14 -155 SUS at 100 F., a viscosity index of 107, and a Conradson carbon residue of 0.05.

A Mid-Continent solvent extracted distillate with normal viscosity at 100 F. of SUS. 1og sianie as footnote 11, but the viscosity is 300 8138- at 13 Mid-Continent solvent extracted distillate falling within SAE-lO grade.

14 Same as footnote 13, but falls within SAE-50 grade.

I ll after about 250 hours indicates that the test oil had fairly good detergency properties.

Sludge dispersancy test-Sludge collected from automobile engine oil filters is dried by blowing with nitrogen at an elevated temperature. Ten grams of this sludge, 89 grams of an oil solution of the additive being tested, and one gram of water are stirred and then allowed to stand for 24 hours at a constant temperature in a standard cylinder. At the end of this period, the top 25 ml. of suspension is withdrawn, diluted with a light petroleum ether and centrifuged to precipitate the sludge. The volume of sludge precipitated is recorded as a percentage of the sludge originally present in that top 25 ml. at the start of the standing period.

EXAMPLE I Formulations l and 2 were tested in the Caterpillar L-l Test with the results shown in the following table:

Fuel: 0.4 wt. percent Sulfur MILL-2104A.

Formulation l Formulation 2 Demerit 120 hrs. 240 hrs. 120 hrs. 240 hrs.

Ring zne. 0.25 0.28 0. 72 1. 13 Ring zone-1 0.02 0.01 0. 02 0.05 Top groove fill, percent 3 6 31 56 Oil, consumption, 1b 1. 74 1. 1. 50

12 tests. It is at once apparent from FIGURE I that Formulation 4, made in accordance with the teachings of this invention, is substantially superior to the prior art compositions, Formulations 2 and 3.

The following table shows the final individual parts inspections from these tests:

The above table clearly illustrates that Formulation 4, containing the combination of the neutralized phosphosulfurized polymeric hydrocarbon and the multi-functional polar copolymer, gives outstanding results when used in automotive engines, particularly under conditions of low temperature driving. The used oil inspections from these tests indicate that in addition to the outsanding engine cleanliness of Formulation 4, there was far less sludge in the used oil as compared to Formulations 2 and 3. This clearly indicates that in addition to good sludge suspending ability, the additive combination of this invention also markedly inhibits the formation of sludge or sludge precursors.

EXAMPLE III Formulations 5, 6 and 7 were also tested in the low temperature sludge test.

TABLE III Effect of detergents on inhibiting sludge formation 550 hour 220 hour analysis 440 hour analysis analysis (end of test) Oil 2 Form. Form. Form. Form. Form. Form, Form. Form,

Sludge deposits on engine (visual rating of 9 parts), I

sludge rating, percent 9 8 5 4 25 11 6 l3 7 Organic sludge in oil-insoluble resins 24 51 16 7 :14 43 13 47 15 Percent reduction in engine sludge deposits 80 -60 20 -130 46 Percent reduction of organic sludge formed in 011-.-- -50 -2l9 56 2 70 68 1 Base case.

test which correlates with passenger car stop-and-go low temperature driving. The test employs a high rate of blow-by of combustion chamber gases, and includes about 75 hours of very rich idle (air/fuel ratio-9.5:1). The fuel used was a commercial grade of leaded gasoline having the following properties:

Research octane number 90.8

Olefins, percent 10.0

Aromatics, percent 19.1

Saturates, percent 70.9

Sulfur, percent 0.017

Gravity, API 62 Reid vapor pressure 9.7

Gum 3.8 mg./100 ml.

Table III clearly illustrates that Formulation 7, made in accordance with the teachings of this invention, is far superior in preventing sludge and in handling sludge once formed, than are the closely related prior art Formulations 5 and 6. The superior performance of Formulation 7 becomes more pronounced as the test is extended to 440 and 550 hours, which materially increases the tests severity. The results of the tests on Formulations 6 and 7 are graphically plotted in FIGURE II. The oil base without the detergent-inhibitor, or Aciyloid 966, was also run, and the results are included in the table and in FIGURE II.

The upper chart of FIGURE II displays the inhibition of sludge formation in the oil as a result of the additives at different periods of time during the test. The lower chart in FIGURE II illustrates the inhibition of sludge deposits because of the additives as plotted against the time of the test. FIGURE 'II clearly shows the superior performance of Formulation 7 of this invention, as compared to Formulation 6 and the non-additive oil.

EXAMPLE IV The following table gives additional examples of multifunctional, surface active, detergent polymers that can be used according to this invention in combination with phosphosulfurized neutralized hydrocarbons. Specifical- 1y, for example, 4 weight percent of the detergent polymers given below are used with 4 weight percent of the detergent-inhibitor of Formulation l in Oil No. 3 to obtain a lubricating oil. In the examples of the following table the materials are admitted to a 20-gallon stainless steel kettle and heated to 60-65 C. and held at this temperature for 15-20 hours until a molecular weight of about 30,00035,000 is achieved. After this, the polymer obtained is stripped under vacuum to remove any unreacted materials.

From reduction of coconut acids saturated straight chain CID-C18, typically approximately 3% C10, 61% C12, 23% C14, 11% Cm and 2% C18 alcohols.

Another commercially available additive that can be used as a dispersant polymer according to this invention is made by esterifying methacrylate acid with diethylaminoethanol, which ester is then copoly-merized with mixed C C methacrylates. Specifically, weight percent of an oil concentrate of this copolymer is admixed with 4 weight percent of the detergent-inhibitor of Formulation 1, in 45 weight percent of Oil 1 and 46 weight percent of Oil 2.

EXAMPLE V An improved fuel for use in aircraft is formulated as follows:

Weight percent Multi-functional polymer 0.01 Neutralized phosphosulfurized polybutene 0.01 JP5 m'l 99.98

The multi-functional polymer used is polymer C of Example 4. The JP-5 oil is derived from a Coastal crude. The neutralized phosphosulfurized hydrocarbon is obtained as follows:

Ninety parts of a polyisobutylene having an average molecular weight of about 1100 are reacted with nine parts by weight of phosphorus pentasulfide for ten hours at 425 F. with stirring and nitrogen blowing. The product does not require filtration. It has a phosphorus content of 2.5 weight percent, a sulfur content of 4.3

weight percent, a neutralization and a saponification nurn- 6 her to a pH of 4 of 26.4 and 65.8 respectively. The agent used to neutralize the phosphosnlfurized hydrocarbon is the high barium synthetic sulfonate previously mentioned. One part of the phosphosulfurized hydrocarbon is reacted with two parts by weight of the sulfonate for six hours at 350 F. while dissolved in an equal weight (of combined reactants) of a solvent extracted mineral oil having a viscosity of 100 SSU at 210 F. The mixture is then cooled to 250 F. and filtered.

14 I EXAMPLE VI An improved aviation engine oil is formulated 'as follows:

Volume percent Maleic anhydride polymer concentrate 8.00 Neutralized phosphosulfurized hydrocarbon 5.15 Synthetic oil 86.85

Di-Z-ethylhexyl sebacate Complex esters 5 which has added to it:

Weight percent Tricresyl phosphate 3 Phenothiazine 1 Silicone (60,000 cs) 0.001

The complex ester has a structure: alcohol-dibasic acidglycol-di-basic acid-alcohol.

More fully:

[2=eth-yl hexyl sebacate]-[sebacic acid]-[polyethylene glycol (200)1-[sebacic acid]-[2-ethyl hexyl sebacate] It is more fully described in U.S. Patent Re. 24,287.

The neutralized phosphosulfurized hydrocarbon is made as follows:

Ten parts of a 'deasphalted dewaxed Panhandle residuum having a viscosity index of 95, a gravity of 248 API, and a viscosity of 165 S.S.U. at 210 F. are heated with one part by weight of phosphorus pentasulfide for ten hours at 450 F. while being blown with nitrogen. The product is cooled and filtered at 250 F. It has a phosphorus content of 2.46 weight percent, a sulfur content of 4.35 weight percent, a neutralization and saponification number to a pH of 4 of 29.8 and 72.45 respectively. This phosphosulfurized residuum is neutralized with an alkaline barium alkyl phenate. One part of an alkylated phenol (predominantly a wide cut nony-l phenol from the alkylation of phenol With tripropy lene) is dissolved in 1.5 parts of a phenol extracted, solvent dewaxed paraflinic oil (vis. F. of S.S.U.) and 1.3 parts of barium hydroxide penta hydrate are slowly added over a period of an hour. The reaction takes 2% hours at an average temperature of 250 F. During the last hour, the mixture is kept saturated with CO A 58.3 weight percent solution of the product in light kerosene is then prepared and filtered. It has the following inspections:

Sulfated ash, wt. percent 18.0 Carbonate ion, wt. percent 2.7

Equal parts of the phosphosnlfurized hydrocarbon, of the neutralizing agent, and a solvent extracted diluent oil are then heated for one hour at 275 F. with stirring and nitrogen blowing to obtain the final product.

The invention having been described, what is sought to be protected by Letters Patent is succinctly set forth in the following claim.

What is claimed is:

As an additive combination for mineral oil lubricants to impart dispersancy and oxidation resistance thereto: one part by weight of a neutralized, oil-soluble, metalcontaininlg phosphosnlfurized polyisobutylene detergent additive; and 0.2 to 3.0 parts by weight of an oil-soluble, multi-functional surface active copolymer that has a molecular weight in the range of 5,000 to 200,000, disperses more than 70 weight percent sludge in the sludge dispersancy test at 10 weight percent concentration in a test oil, and in 3.6 weight percent concentration raised the viscosity index of a parafiinic solvent extracted neu-.

tral lubricating oil having an initial viscosity of 46 S.U.S. at 210 F. and viscosity index of 113 by at least 20 units; said detergent additive being a phosphosulfurized polyisobutylene polymer initially having a molecular weight in the range of 1,000 to 50,000 neutralized by reaction with barium alkyl phenate sulfide and barium sulfonate at a temperature in the range of 280 to 450 F. for at least 0.5 hour while maintaining at all times the water content of the reaction mixture below 0.5 weight percent, said barium alkyl phenate sulfide being prepared by neutralizing alkyl phenol sulfide having C to C alkyl groups with barium hydroxide and then CO treating to obtain a barium alkyl phenate sulfide containing 12 to 12.8 wt. percent barium, 2.8 to 3.3 wt. percent sulfur, and having a pH of about 11 and a neutralization number to a pH of 4 to 73 to 93, said barium sulfonate being obtained by neutralizing a sulfonic acid having a molecular weight 16 in the range of 200 to 900, and said oil-soluble surface active copolymer consisting essentially of 4 to 15 wt. percent N-vinyl-2-pyrrolidone, about 10 to 20 wt. percent vinyl acetate and 65 to 86 wt. percent of dialkyl fumarate wherein said alkyl groups contain 9 to 12 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,416,281 Berger et al Feb. 25, 1947 2,538,696 May Jan. 16, 1951 2,736,701 Neff Feb. 28, 1956 2,767,164 Asseif et al. Oct. 16, 1956 2,849,398 Moody et a1. Aug. 26, 1958 2,866,729 Zimpel Dec. 30, 1958 2,892,792 Stewart et a1. June 30, 1959 FOREIGN PATENTS 758,203 Great Britain Oct. 3, 1956 760,554 Great Britain Oct. 31, 1956 788,408 Great Britain Jan. 2, 1958

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