US2758085A - Method for incorporating oil-insoluble, solid addition agents in mineral oils - Google Patents

Description

United Statcs Patent ll/IETHOD FORLINCORPORATING OIL-INSOLUBLE, SOLID ADDITION AGENTS IN MINERAL OILS Edward:A..0berright, Woodbury, N. J., assignor to SoggmygMobil-Oil Company, Inc., a corporation of New or i No Drawing. Application June 8, 1953, Serial No; 360,349

4 Claims. (Cl. 252'-25) This invention relates generally to improved lubricating oil compositions. More particularly, it relates to a novel means for the incorporation of certain improving agents into lubricating oils and to a novel form of such addition agents.

As is wellknown, it is the practice in the art today to add.to lubricating. oils minor amounts of chemical agents to improvevarious lubricating characteristics of such-oils. A greatnumber and varietyof such improving agents are known. The present invention is directed primarily to solid lubricating oiladdition agents of the inorganic type which are insoluble in lubricating oils. These include particularly the oxides, hydroxides and carbonates of the alkali and alkaline earth metals, such as potassium hydroxide, sodium hydroxide, calcium oxide, calcium hydroxide, calcium carbonate, barium hydroxide, strontium hydroxide, zinc oxide, etc. However, the principle of the invention is applicable to solid inorganic type, oil-insoluble addition agents in general. Although these additives. are insoluble in engine lubricating oils, they may be dispersed therein and, when so dispersed, they provide highly desirable improvements in the oil. Thus, they inhibit increase ofacidify of the oil'in use so that corrosion of the. engine parts with which the oil comes in contact is substantially reduced. They also improve the detergent character. of

the oil; so that the deposition of sludge on the engineparts is effectively reduced. Due to the high efiectiveness thus exhibited by these additives, as Well as their relatively low cost andavailability, their use in engine oils is highly desirable. However, the fact that they are insoluble in the oil constitutes a serious drawback to their usefrom the marketing angle. Thus, the oil containing the dispersed' additivehas a cloudy appearance. Also, on long standing the additive tends to settle out of the oil. Actually, the cloudy appearance of the oil does not detract fromitsquality, nor does the settling out'of'theadditive affect 'its etfi'ciencysince, in the engine, the additive is re-' dispersed in the oil whenever the engine is startedup.

However, the. cloudy appearance of the oil creates a doubt in the customers mind as to its quality. Away of "utiliz ing thednorganic addition agents which would'solve the" problemiof customerresistancewas, therefore, sought.

A possible solution which suggested itself was that these additives could be marketed separately for addition to the oil at the: point ofuse, i. e., in the engine, rather than at the point of manufacture. In this-way, the beneficial use f..these additives would be attaineclwhile the marketing problem would'be eliminated. Such a .manner: of use, however, posed the further problem of-supplying-theadditives in, a form which would be convenient forrhandling andwhich at the same time wouldbeefiiciently dispersible in.the oil. To give a ready, dispersion til]. the oil, these solid, inorganic additives must be added to the oil .in finely divided form; i. e., the particle size should be no greater than about 45 microns; Distributionlof the additives in this form, however, would not befeasibleior several reasons. In-the -first-place;itwouldbe'costly, since separate, weighed portions, or dosages, of the additives would have ICC 2, to be prepared and. packaged in some manner for such distribution. Also, thisform of the additive would be unattractive from the marketing angle. The object of this-invention is, therefore, to provide a means for. the utilization of these additives which is convenient and practicable as well as attractive from the marketing standpoint. A further object is the provisionof a novel form of these addition agents for addition to lubricating oils.at the point of use. Other and further objects of the invention will become apparent from the followingdescription thereof.

The present invention provides a mostconvenient and practicable form of the solid,. inorganic, oil-insoluble addition agents. This novel'form of additive comprises solid, composite pellets of the finely divided. additive and' a wax binding material. In this form the additives may be added to the lubricatingoilat the point of use, such as in the crankcase of an engine,.and provide a ready dispersionof the, additive in the oil;

In accordance with the invention, the additive is.prepared as follows: The additiveis ground, ifnecessary, and passedthrough a 325' mesl1 screentoiprovide a particle size not greater than approximately45 microns. A wax, such as a paraflin wax, is-heatedabove its melting point and the comminuted additive is mixed with the liquid wax, with stirring, to provide a homogeneous dispersion of theadditive: in the wax; This-mixture iscthen formed into pellets in anysuitablewmanner, such as by pouring-it into molds-andallowing it to cool .and solidify.

The;unique.advantage.. of the pellets of the invention .is that'the additive is maintaineditherein.in a finely divided; readily dispersible, state. Upon addition-of" the pellets" to the. oil, the. wax-1 component. dissolves. and the; finelyv divided: additive is. simultaneously dispersed. in. the Oilxi. Compacted pellets of the addition agents per se, on:the-: other hand, will not'give. a-satisfactory dispersion ofr'the additive inthe oil, evenwhenzthe. engine is operatedfori a considerable period.

The wax used in forming the pellets of therinve-ntion' may be any oil-soluble wax, or wax-like material, which, is solidat temperatures up to at least 10O 125 F. Suitable Waxes are, for example, parafi'n Wax, japan wax, carnuba wax, beeswax, spermaceti, 1 octadecanol, etc;, paraffin' Wax' being particularly preferred.

The following examples show the utility oft'he invention from the standpoint of providing the effective disper. sion of solid addition agent upon addition to the lubricat-' ing oil in an internalcombustiorr engine.

EXAMPLEI Zinc. oxideewax pellets Zinc" oxide was prepared in Y the form of zinc oxide waxpellets -as'-follows. Powdered zinc oxide was passed through a32 5 mesh screento provide aparticle sizeof' not greater thanASm-icmnsand then mixed with' hot, liquid "paraffin wax (melting point 1204 25 F.) and the: heated mixturesfirred thoroughly. The mixture was them poured into a=series-of"molds' andall'owed tocool and solidify; The'pell'ets thus ob'taincd' contained 40% -by' Weightof zinc oxide:

The pellets were: tested in i the" Lausorn Oxidation- S't-a bility Test OS'--2: This-"test-involves thie operation-of" the single cylinder," 4 cycle li'q-uid cooledengine for hours under the following conditions:

One-half "throttle 13."01 air-fuel' ratio Oil addd "every;20 hours i The test determines oil deterioration as primarily indicated by corrosion of the copper-lead bearing and secondarily by engine cleanliness. The copper-lead bearing of the engine is accurately weighed before and after the test run and the loss in weight thereof recorded. The engine which is clean at the start of the test is inspected after the test run for cleanliness of the rings, lands, ring grooves and piston skirt. Cleanliness ratings are made, based on a scale of from 100 to zero, a rating of 100 signifying a perfectly clean engine and a rating of zero representing the worst possible deposit condition.

To test the pellets, a sufficient number thereof were added to the base oil, an S. A. E. 20 grade Pennsylvania motor oil, in the crankcase of the engine, via the oil addition tube, to give a 0.5% weight concentration of zinc oxide in the oil. With each addition of make-up oil, sufficient pellets were added to maintain this original additive concentration. The fuel used was a blended gasoline comprising 40% thermal plus 30% catalytically cracked plus 30% straight run plus 2.5 cc. of TEL. A control test was also conducted on the base oil alone.

The test with the base oil alone showed a bearing weight loss of 394 milligrams per half-bearing and an engine cleanliness rating of 77, while the test utilizing the zinc oxide-wax pellets showed a bearing weight loss of 76 milligrams per one-half bearing and an engine cleanliness rating of 82.

EXAMPLE II Calcium hydroxide-wax pellets A high grade of calcium hydroxide, known as Greasemakers Lime, was ground and passed through a 325- mesh screen and stirred into hot, liquid scale wax (melting point 125-127 F.). The stirring was continued for /2 hour after the addition of the lime to insure a homogeneous mixture. The mixture was then poured into molds and allowed to cool and solidifidy. The pellets thus obtained contained 31% by weight of calcium hydroxide.

The pellets were tested in the Lauson D-4A Detergency Test. This test involves the operation of the single cylinder, 4-cycle, liquid cooled engine for 100 hours under the following conditions:

Oil temperature F 225 Jacket temperature F 275 Speed R. P. M 1825 Brake load H. P 1.6

One-half throttle 13-1 air-fuel ratio Oil added every 20 hours This test determines the efiectiveness of the lubricating oil in preventing fouling as measured by the cleanliness of the rings, lands, ring grooves and piston skirts. Engine cleanliness ratings are assigned on a scale of 100 to zero in the same manner as for the Lauson OS-2 Test.

To test the calcium hydroxide-wax pellets, a suflieient number of the pellets were added to the base oil in the crankcase of the engine, via the oil-addition tube, to provide 1% by Weight of calcium hydroxide in the engine oil. The base oil used was an S. A. E. 20 grade Pennsylvania motor oil. With each addition of make-up oil during the test run, sufiicient pellets were added to maintain this original additive concentration. The fuel used was the same as defined in Example I. A test was conducted on the base oil also as a control.

The test conducted on the oil alone gave an engine cleanliness rating of 65, while the test using the calcium hydroxide-wax pellets gave a rating of 80.

The size of the pellets and the proportion of additive therein can, of course, be controlled. The pellets may contain as little as about and up to 90% of the additive. Generally, it is preferred to so design the pellets that one pellet will supply the required improving amount of additive for a specified quantity of oil. The

number of pellets to be added in any case is then determined by the volume of oil to be treated. For use in automobile engines the pellets will be of relatively small size since the amount of additive required is ordinarily small, i. e., from about 0.1% to about 10% by weight; and, a pellet comprised, for example, of 50% addition agent and 50% binding material and weighing 16 grams will supply 1% of additive to one quart of oil.

Although, as heretofore indicated, the principle of this invention is primarily applicable to the incorporation in oil of the solid, oil-insoluble, inorganic-type addition agents, it will be appreciated that it may be advanta geously applied to any solid-type additive, including the elemental metals and solid, oil-soluble, organic addition agents, since it provides a convenient means of adding controlled amounts of such additives to the oil at the point of use, whereby the oil is fortified to meet special operational conditions, or refortified as the addition agents originally present therein become depleted by use. The invention may also find useful application in the addition of additives to hydrocarbon fractions, other than lubricating oils, such as fuel oils, gasolines, etc.

Having now fully described the invention, what is claimed as new and patentable is:

l. A method for incorporating an oil-insoluble, solid, addition agent into a mineral oil fraction, which comprises (1) comminuting the addition agent to an average particle size no greater than about 45 microns, (2) forming a compacted pellet comprising from about 10% to about by weight, of the comminuted addition agent and from about 90% to about 10%, by weight, of a wax binder and (3) adding the said pellet to the mineral oil fraction.

2. A method for incorporating a solid, inorganic basic compound, selected from the group consisting of the metal oxides and hydroxides of the metals of Group II of Mendeleeffs Periodic Table of the Elements, into a mineral lubricating oil which comprises (1) comminuting the said compound to an average particle size no greater than about 45 microns, (2) forming a compacted pellet comprising from about 10% to about 90%, by weight, of the comminuted solid basic compound and from about 90% to about 10%, by weight, of a wax binder and (3) adding the said pellet to the oil.

3. A method for incorporating solid zinc oxide into a mineral lubricating oil which comprises 1) comminuting the zinc oxide to an average particle size no greater than about 45 microns, (2) forming a compacted pellet comprising from about 10% to about 90%, by weight, of the comminuted zinc oxide and from about 90% to about 10%, by weight, of a wax binder and (3) adding the said pellet to the oil.

4. A method for incorporating solid calcium hydroxide into a mineral lubricating oil which comprises (1) comminuting the calcium hydroxide to an average particle size no greater than about 45 microns, (2) forming a compacted pellet comprising from about 10% to about 90%, by weight, of the comminuted calcium hydroxide and from about 90% to about 10%, by weight, of a wax binder and (3) adding the said pellet to the oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,699,274 Bohart Jan. 15, 1928 2,079,051 Sullivan May 4, 1937 2,110,503 Duckham Mar. 8, 1938 2,292,047 Calhoun Aug. 4, 1942 2,485,861 Campbell et al Oct. 25, 1949 2,671,758 Vinograd et a1 Mar. 9, 1954 2,676,925 Lindstrom et a1 Apr. 27, 1954 FOREIGN PATENTS 360,121 Great Britain Nov. 5, 1931

Claims (1)

1. A METHOD FOR INCORPORATING OIL-INSOLUBLE, SOLID, ADDITION AGENT INTO A MINERAL OIL FRACTION, WHICH COMPRISES (1) COMMINUTING THE ADDITION AGENT TO AN AVERAGE PARTICLE SIZE NO GREATER THAN ABOUT 45 MICRONS, (2) FORMING A COMPACTED PELLET COMPRISING FROM ABOUT 10% TO ABOUT 90%, BY WEIGHT, OF THE COMMINUTED ADDITION AGENT AND FROM ABOUT 90% TO ABOUT 10%, BY WEIGHT, OF A WAX BINDER AND (3) ADDING THE SAID PELLET TO THE MINERAL OIL FRACTION.