Newingham, Thomas D. (Broomall, PA)
Amaroso, James R. (Newton Square, PA)
Coppock, Walter J. (Wallingford, PA)
Williams, Edward S. (Claymont, DE)

05/246997

12/17/1974

04/24/1972

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Sun Oil Company of Pennsylvania (Philadelphia, PA)

508/297

585/5, 585/4, 585/3, 585/12, 184/109, 585/13, 508/591, 184/6.260, 585/11

C10M169/04; C10M171/00; C10M177/00; C10M169/00; C10M1/28; C10M1/18; C10M9/00

252/15,56R,59 184/1E,6.26

3607749

VISCOSITY INDEX IMPROVERS

September 1971

Forbes

Wyman, Daniel E.

Vaughn I.

Church, George Hess Edward Bisson Barry L. J. A.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of our application Ser. No. 140,398, filed May 5, 1971 and claims any benefit which can be accorded thereto under 35 USC 120 with respect to Ser. No. 178,193, filed Sept. 7, 1971 of Robert P. Bryer, William W. Crouse, Jr., John Q. Griffith, III, Thomas D. Newingham, William H, Reiland, Jr., Ronaold W. Reynolds, Sheldon L. Thompson and Edward S. Williams.

The invention claimed is

1. A process of lubrication which comprises:

2. A process as in claim 1 wherein said polymeric additive is a mixture of a polystyrene and a depersant type polymethacrylate terpolymer which has been grafted with N-vinyl pyrrolidone.

3. A process as in claim 1 wherein the polystyrene polymeric additive is selected from polymers of styrene, α-methylsytrene and β-methylstyrene.

4. A process according to claim 1 wherein said polymeric additive has a viscosity average molecular weight in the range of 200,000-400,000.

5. A process according to claim 1 wherein said lubrication zone includes the bearings of cold rolling machinery for steel.

6. A process according to claim 1 wherein said polymeric additive comprises a polystyrene and at least one dispersant type polymethacrylate copolymer which has been grafted witih N-vinyl pyrrolidone.

7. A process according to claim 6 wherein said acrylic polymer contains at least one alkyl group in the 6 to 30 carbon number range.

The following patents and applications are related to the disclosure of the present application in that they disclose additives and/or methods of obtaining oils which can be used in the mist lubrication process and composition of the present invention.

The disclosure of all the following applications and patents is hereby incorporated in the present application:

SERIAL FILING PATENT ISSUE NO. DATE NO. DATE TITLE ____________________________________________________________ ______________ 873,008 10-31-69 now abandoned Oil and Process of Manufacture of Blended Hydrorefined Oil-- Ivor W. Mills & Glenn R. Dimeler 874,087 10-27-69 3,706,653 12-19-72 Light Colored Highly Aromatic Oil and Pro- cess of Preparation-- Ivor W. Mills, Glenn R. Dimeler & Merritt C. Kirk, Jr. 16,495 3-4-70 3,673,078 6-27-72 Process for Producing High UR Oil by Hydro- generation of Dewaxed Raffinate--Merritt C. Kirk, Jr. 70,590 9-8-70 3,732,154 5-8-73 Catalytic Hydrofini- shing of Lube Oil Pro- duct of Solvent Extrac- tion of Petroleum Dis- tillate--Ivor W. Mills, Merritt C. Kirk, Jr. & Albert T. Olenzak 140,398 5-5-71 now abandoned Mist Lubricant Containing Polymeric Additive-- James R. Amaroso, Walter J. Coppock, Thomas D. Newingham & Edward S. Williams 178,193 9-7-71 Composition Comprising Stabilized Hydrocracked Lube and an Antioxidant-- Robert P. Bryer, William W. Crouse, Jr., John Q. Griffith, III, Thomas D. Newingham, William H. Reiland, Jr., Ronald W. Reynolds, Sheldon L. Thompson & Edward S. Williams 178,479 9-7-71 3,816,316 6-11-74 Soap Thickened Hydraulic Oil Composition--John Q. Griffith, III, Edward S. Williams & William H. Reiland, Jr. 228,832 2-24-72 Hydrorefined Lube Oil and Process of Manufac- ture--Ivor W. Mills & G Glenn R. Dimeler 240,806 4-4-72 3,813,338 5-28-74 Improved Textile Machi- nery Lubricant Composi- tion--Walter J. Coppock, James R. Amaroso & John Q. Griffith, III ____________________________________________________________ ______________

SUMMARY OF THE INVENTION

One aspect of our invention is a process of lubrication which comprises:

a. converting into an aerosol a mixture of a mineral lubricating oil having an SUS viscosity in the range of 100 to 3000 at 100° F. with an effective amount of a polymer additive selected from the group consisting of polyolefins, polystyrenes, polyacrylate terpolymers, polymethacrylate terpolymers, dispersant type polyacrylates, dispersant type polymethacrylates or mixtures of two or more such polymeric additives, said polymeric additive having a viscosity average molecular weight in the range of 10,000 to two million and said effective amount being sufficient to cause the stray fog produced by said mineral lubricating oil when tested in a Norgren Microfog test apparatus at an oil temperature of 100° F., to be no greater than 10 (more preferred 8) grams per hour and the reclassification to be no less than 0.6 (more preferred 0.8) ounces per hour per 100 bearing inches,

b. pneumatically conducting said aerosol to a zone where lubrication occurs, and

c. reclassifying said aerosol in said zone whereby the oil droplets of the aerosol are coalesced within said lubrication zone (preferably in greater amount than are coalesced in the absence of said additive).

Conventional mineral oil lubricants with nonpolymeric additives are unsatisfactory as mist lubricants in some types of lubrication systems, for example, bearings in some cold rolling machinery. A polymeric additive (polyolefins such as polybutenes, polystyrenes, polyacrylates, dispersant type polyacrylates, polymethacrylates and dispersant type polymethacrylates or mixtures thereof) can be used as additives in mist lubricants to provide the requisite balance of misting and reclassification properties. For a given polymer a very narrow molecular weight range and/or concentration range in the lubricant is required in order to obtain sufficient reclassification for proper lubrication and no visible stray fog. For example, for stray fog of 6 g./hr. or less in a Norgran "Microfog" test apparatus and reclassification of one ounce per hour per 100 bearing inches or greater, a 20% dispersion of a 150,000 viscosity average molecular weight polyisobutylene additive can be used at about 0.2 volume percent (about 0.04 weight percent polymer solids) concentration in a paraffinic or naphthenic lube oil base.

Suitable polystyrenes are the high molecular weight polymers of styrene, a-methylstyrene, b-methylstyrene, etc., including terpolymers and copolymers (e.g., "Lubrizol 3702").

Suitable polyisobutenes are those marketed as "Paratone N." "Paratac" and "Paratac 108" (all products of Enjay Chemical Company). Generally concentrations of such olefin polymers should be no greater than 0.5 volume percent of 10 to 50 weight percent solids lubricant composition (preferably less than 0.1 weight percent solids).

Especially good results are obtained when polyisobutylene is used in combination with a polyacrylate (which can be of the dispersant type). Preferred polyacrylates (including polymethacrylates) are the terpolymer types, in contrast to copolymers. The polyisobutylenes are excellent additives for suppressing stray fog but they tend to decrease the total oil output to an unsatifactory level. In contrast, the polymethacrylates provide excellent oil output, but are relatively inefficient in reducing stray fog. A combination of these two classes of polymer provides a satisfactory lubricant with regard to both stray fog and total output. In general the polymethacrylate additive will have a viscosity average molecular weight in the range of 75,000 to 260,000 and can be used in concentrations of range of 0.05 to 4 volume percent (of materials containing 10 to 70 weight % polymer in a diluent). The polyisobutylenes will have a viscosity average molecular weight in the range of 10,000 to 2,000,000 and can be used at concentrations in the range of 0.05 to 2.0 volume percent, but preferably less than 0.5% (of materials containing 10 to 70 weight percent of polymer in a diluent). That is, on a 100% polymer basis, the lubricant can contain in the range of 0.005-1.5 wt. % polymer, more preferably in the range of 0.01-0.35% of polyisobutylene.

Preferred acrylates and methacrylates of the nondispersant type correspond to the structural formula: ##SPC1##

where n is an integer such that the viscosity average molecular weight (VAMW) is in the range of 10,000 to 2,000,000, more preferred and within the range of 0.5-2 wt. % solides in the final mist oil the preferred VAMW is the range of 200,000 to 400,000 and where R is H, for the acrylates and methyl for the methacrylates. In the copolymer type materials, R' is a single alkyl radical (branched or normal) having a carbon number in the range of 6 to about 30, preferably eight to 24 (usually an even number). In the preferred terpolymer types of materials at least two different alkyl radicals (in the above carbon number ranges) are present in the polymer chain (e.g., normal octyl and normal decyl or each of the even numbered normal alcohols in the C ₁₀ -C ₂₂ range). In the dispersant type materials the above-noted copolymers or terpolymers have been grafted with N-vinyl pyrrolidone. Descriptions of such polymers can be found in U.S. Pat. Nos. 2,091,627, issued Aug. 31, 1937 to Herman A. Bruson; 2,489,671, issued Nov. 29, 1949 to Anthony J. Revukas; 3,252,949, issued May 24, 1966 to J. E. Fields et al.; 3,417,021, issued Dec. 17, 1968 to John E. Engelhart and 3,510,425, issued May 5, 1970 to Timothy C. Wilson.

An especially preferred polymethacrylate is that sold by Rohm and Haas under the trade name "PL 10190" (which has a molecular weight of about 100,000 and is of the same chemical structure as the "700 Series"). Two operable polyisobutylenes are "Paratone N" (which has a Staudinger molecular weight of about 20,000 and contains about 20% polymer and "Paratac 108" (which has a Staudinger molecular weight of about 10,000 and contains about 35 wt. % polymer in 150 SUS at 100° F mineral oil.

A mixture of 10 parts by weight of 300,000 VAMW methacrylate terpolymer, wherein two or more of the alkyl groups are in the C ₁₂ -C ₂₄ range and 1 to 4 parts by weight of a 150,000 VAMW polyisobutylene is especially useful as a polymeric additive in a mist lubricant. Also useful is the dispersant type polymethacrylate terpolymer sold as "Acryloid 966S." A useful acrylic is "Acryloid 162."

The preferred lubricant base stocks are naphthenic and paraffinic lubes having a viscosity in the range of 100 to 3000 SUS at 100° F. The paraffinic lubes are generally solvent dewaxed (e.g., to a pour point of 0° F. or less) and solvent refined and have an ASTM viscosity index in the range of 90-130 and a viscosity-gravity constant less than 0.82. The paraffinic lube can be hydrorefined or hydrocracked or hydroisomerized. Blends of such paraffinic lubes with napthenic lubes of about the same viscosity range, or more preferred, with hydrorefined naphthenic lubes can also be used. In general the naphthenic component is preferred in the low viscosity oils (e.g., 100 to 600 SUS at 100° F.) since a higher V.I. is generally preferred in higher viscosity base oils. The naphthenic oil can include those oils classified as "relatively naphthenic" and can have a viscosity-gravity constant in the range of 0.820-0.899, more preferred 0.850-0.899, and is preferably free of naphthenic acids. The preferred naphthenic oil is hydrorefined and has an ultraviolet absorptivity at 260 millimicrons (i.e., 260 UVA) that is at least 40% lower than the 260 UVA of the unhydrorefined oil (e.g., the charge to the hydrorefining step).

The hydrorefining (whether of paraffinic or napththenic oils) can be by such process as those described in U.S. Pat. Nos. 3,502,567, issued Mar. 24, 1970, of Mills and Dimeler; 3,619,414, issued Nov. 9, 1971, of Mills, Kirk and Olenzak and 3,653,127, issued Apr. 4, 1972, of Mills, Dimeler, Atkinson and Hoffman. The hydroisomerized paraffinic (or mildly naphthenic lubes) can be made by the processes described in United States Patent 3,658,689, issued Apr. 25, 1972 of Steinmetz and Barmby, and the hydrocracked paraffinic oil can be made by such processes as those described in U.S. Pat. Nos. 3,579,437, issued May 18, 1971, of Wentzheimer, Reynolds and Chalpin; 3,579,435, issued Nov. 19, 1970 to Olenzak and Thompson and 3,617,484 issued Nov. 2, 1971 to Thompson, Olenzak, Kraus and Steinmetz. Any of these oils (whether hydrocracked, hydrorefined or hydroisomerized) can be extracted with an aromatic selective solvent (such as furfural, phenol, etc.) either before or after the hydrocracking, hydrorefining or hydroisomerization step. The oils can be subjected to additional finishing as with an adsorbent (e.g., activated carbon,) attapulgite, acid-activated montmorillorite, bauxite, molecular sieve zeolites, spent cracking catalyst or mixtures thereof) and/or acid contacting (e.g., HF, H ₂ SO ₄ , HCl etc.) followed by neutralization.

An especially preferred mist lubricant composition comprises an effective amount of the polymeric additive to suppress stray fog and a hydrocracked paraffinic oil (preferably solvent extracted or hydrorefined to reduce or inhibit sludging on exposure to light) having a viscosity in the range of 80-3000 SUS at 100° F., and an oxidation inhibitor in amount effective to permit said composition to pass the ASTM D-943 oxidation test for a period of at least 200 hours, (more preferred 300 hours) said amount being less than would be required to permit the same D-943 test performance for a similar composition wherein the hydrocracked lube oil is replaced by an unhydrocracked solvent refined lube or the same viscosity, VGC and viscosity index. When the hydrocracked oil is stabilized by extraction or hydroefining, said D-943 life will be less than if an unstabilized hydrocracked lube is used; however, the composition containing the stabilized oil can typically have improved thermal stability and resistance to degradation on exposure to ultraviolet light.

The following table presents typical properties of stabilized hydrocracked oils which can be used in mist lubrication according to the present invention:

Properties of Hydrocracked Oils*

Properties of Hydrocracked Oils* ______________________________________ Aniline Viscosity ASTM Gravity Wt.% Point (SUS, 100°F.) VI API Aromatics °F. ______________________________________ 100 103 34.2 12 220 200 107 33.3 11 235 500 107 31.5 13 250 ______________________________________

The preferred antioxidants include the zinc organo thiophosphates (e.g., zinc dialkyl dithiophosphates), the substituted phenols and methylene bridged polyalkyl phenols (e.g., ditertiary-butyl paracresol; 2,6-ditertiary butyl phenol; 4,4'-methylenebis (2,6-ditert-butyl phenol, etc.). The amine types (e.g., phenylene diamine; 2,6-ditert-butyl-alphadimethylamino-p-cresol; N,N'-di-sec-butyl-p-phenediamine N,N'-diisopropyl-p-phenylenediamine, etc.).

In mist lube composition containing a solvent refined paraffinic lube, the oxidation inhibitor concentration can be reduced when 85-100% of the solvent refined lube is replaced by the stabilized hydrocracked oil.

Also in some mist lubricant formulations which contain a solvent refined paraffinic lube, the partial or whole substitution of a hydrocracked (preferably, a stabilized hydrocracked) lube permits the use of a lower concentration of the polymeric additive for a given degree of stray fog. This provides improved reclassification perforamance (for a given degree of stray fog) in the composition containing the hydrocracked lube. Alternatively, a lower molecular weight polymer can be used in the composition containing the hydrocracked lube.

Where the lubrication system in which the mist oil is to be used has rubber seals it is preferred that the base oil contain napthenic oils, such as a blend of paraffinic and napthenic oils (including hydrorefined oils and "raw napthenic distillate") having an aniline point in the range of 150°-170° F. in order to maintain the seals in properly swelled condition. With silicone rubber seals the preferred aniline poing is in the range of 195°-215° F.

It is also preferred that the basic nitrogen content of the base lubricant be as low as possible, preferably less than 5 p.p.m. nitrogen, more preferred less than 1 p,p,m., since it has been discovered that basic nitrogen compounds in lubricating oils cause skin irritation.

BRIEF DESCRIPTION OF THE DRAWING

In the attached drawing, FIG. 1 illustrates the relationship between the two major desired properties of a mist lubricant, expressed, in FIG. 1, as a function of the molecular weight of the polymeric additive and, in FIG. 2, as a function of the volume percent of the polymer dispersion. It can be seen that, at a given concentration of the methacrylic polymer, only a very narrow molecular weight range will produce a mist oil having the requisite stray fog and reclassification properties. In FIG. 1 it can be seen that a viscosity average molecular weight of about 300,000 was necessary in order to produce a satisfactory mist lubricant. In general, with acrylic polymers, particularly polymethacrylates, the viscosity average molecular weight (VAMW) is preferably in the range of 200,000 to 400,000; however, with the dispersant type terpolymer (e.g., "Acryloid 966S") a VAMW as high as two million can be effective at concentrations no greater than 0.5 weight percent polymer.

In FIG. 2, the polymer additive was a commercially available polyisobutylene, "Paratone N." The product contained about 20% solids; therefore the weight percent concentration of polymer on a solids basis in the lubricant is about one-fifth of the indicated volume percent. As can be seen in FIG. 2, only a very narrow concentration of the polyisobutylene additive produced the requisite combination of stray fog and reclassification properties. Note, however, that for some uses the requisites can be a stray fog of 8 grams per hour or less and/or reclassification of 0.6 ounces per hour, or greater, per 100 bearing inches, thus, permitting the use of a lower molecular weight polymer and/or a wider concentration range.

In the studies of FIGS. 1 and 2 the test conditions were: an oil temperature of 120° F., an air temperature of 100° F. in Norgren test apparatus. The study was conducted in a blend of solvent refined paraffinic base oils, the blend having a viscosity at 100° F. of 1500 SUS and a viscosity at 210° F. of 111 SUS (97 V.I.). The polybutene had a viscosity average molecular weight (VAMW) of about 150,00. The acrylic polymers were of the terpolymer, nondispersant type (the "Acryloid 700" series) and were tested at the 1% volume level (the solids content of the polymer dispersions varied between about 20 and 60%; however, with these polymers the concentration variation within this range does not appreciably change the conclusion, shown in FIG. 1, that a terpolymer methacrylate polymer in the 200,000 to 400,000 molecular weight range will produce a mist oil with the desired properties. The tested terpolymer contained at least two different alkyl groups in the C ₁₀ -C ₂₂ range.

ILLUSTRATIVE EXAMPLES

In the following examples all percentages are by weight unless otherwise specified.

EXAMPLE 1

A mist lubricant having a viscosity at 100° F. of 2030 SUS was formulated as follows (all percentages are volume percent): 22% of a solvent refined paraffinic lube containing 15.5 weight percent gel aromatics and having an SUS viscosity of 508 at 100° F. and 64.3 at 210° F.; 75.78% of a paraffinic bright stock containing 24% gel aromatics and having an SUS viscosity at 100° F. 2700 and 165 at 210° F.; 1.72% of "Vanlube 71" (a lead diamyl dithio carbamate); 0.02% of "Acryloid 162" (an acrylic polymer, generally used as a pour depressant); 0.5% of "Acryloid 966S" (a polymethylmethacrylate terpolymer of the dispersant type and having an average molecular weight of about one million and being about 26 weight % polymer solids. The mist lubricant, upon use testing, had superior reclassification properties and the test indicated that the acrylic dispersant polymer was beneficial as an additive in a mist oil.

Similar results can be obtained when the "Vanlube 71" is replaced by zinc dialkyl dithiophosphate or a chlorine-phosphorous additive, such as "Lubrizol 757," or other E.P. additive.

In general such lubricants can be similarly formulated to have any desired viscosity in the range of about 70 to 3000 SUS at 100° F., by suitable choice of the base oil. One good base oil combination is to blend SAE 20 and 30 motor oils.

EXAMPLE II

A mist oil was formulated from 78.0% ¢Sunvis 21" (a solvent refined paraffinic lube containing 13% gel aromatics and having an SUS viscosity at 100° F. of 208 and 47.4 at 210° F.); 19.6 "Sunvis 51" (a solvent refined paraffinic lube containing 15.5% gel aromatics and having an SUS viscosity at 100° F. of 508 and 64.3 at 210° F.); 2.0% "Paratac" (a polyisobutylene dispersion containing about 20 percent polymer solids); and 0.4% "Lubrizol 1360∞ (a conventional additive package of the zinc dithiophosphate type). The formulated mist oil had an SUS viscosity at 100° F. of 295 and 54.5 at 210° F. and as ASTM pour point of +5° F.

EXAMPLE III

A mist oil was formulated containing 31.8% "Sunvis 11" (a solvent refined paraffinic lube containing 12% gel aromatics and having an SUS viscosity at 100° F. of 110 and 46.3 at 210° F.); 59.8% of "Sunvis 21," 8.0% "Paratone N" (a polyisobutylene dispersion containing about 20% polymer) and 0.4% "Lubrizol 1360." The formulated mist oil had an SUS viscosity at 100° F. of 513 and 59.2 at 210° F. and an ASTM pour point of 0° F.

EXAMPLE IV

A mist oil was formulated containing 72.48% "Sunvis 11," 25.95% "Sunvis 51," 0.1% of "Acryloid 162" (an acrylic polymer, generally used as a pour point depressant), 0.3% zinc dithiophosphate, 1.0% "Lubrizol 1734" (a motor oil additive package); 0.15% "Vanderbilt BSN," a neutral barium petroleum sulfonate rust inhibitor and 0.02% Dow Corning defoamer. This mist oil gave satisfactory service when tested for use in Norgren Microfog Lubricators.

EXAMPLE V

A mist oil was formulated containing 22% of "Sunvis 21," 73% of the bright stock of Example I, 1% of a polymethacrylate terpolymer solution of the "nondispersant" type, containing 47.5% polymer and having a viscosity average molecular weight of 290,000 (number average molecular weight 80,000); 0.5% of "Santalube 680" (a mixed phenolic phosphate-sulfonate); 0.1% of "Ortholeum 535" (a mixture of alkyl ammonium mixed acid phosphates); 2.75% of a cosulfurized blend of lard oil and C ₁₈ α-olefins, 0.5% "Ortholeum 162" (a fatty acid phosphate E.P. additive); and 0.02% of a 1% solution of Dow Corning Silicone Defoamer 200 (60,000 cs, at 100° F.).

This mist lubricant was tested for bearings in cold rolling machinery in a steel mill. It exhibited expecially good lubrication properties and satisfactory misting and reclassification properties. Similar lubricants can be formulated having SUS viscosities in the range of 70 to 3000 by suitable choice of the base oil.

The mist oil of this example can be improved (e.g., as in oxidation stability) by substitution, in part or whole, of a hydrocracked paraffinic oil (preferably stabilized) of about the same viscosity for the mixture of "Sunvis 21" and bright stock. Hydrorefined paraffinic oils (e.g., the "Sunvis H" Series) can also be substituted in whole or part for the solvent refined paraffinic oils of this and other examples.

EXAMPLE VI

A conventional way lubricant (useful, for example, in lubrication of lathes for metal working) was made by blending the following

Parts by Volume ______________________________________ Naphthenic distillate (100 SUS at 100°F.) 36.9 Naphthenic distillate (2400 SUS at 100°F.) 55.0 Tallow fatty acid 8.0 ______________________________________

The way lubricant was unsatifactory in a mist lubrication system because of excess stray fog.

EXAMPLE VII

0.1 parts by volume of a commercially available (Paraton N from Enjay Co.) polyisobutylene disperion (about 20 vo. % polymer in 150 SUS at 100° F. in mineral oil) was added to the way lubricant of Example VI. The paraton N had a Staudinger molecular weight of about 20,000. The resulting lubricant performed satisfactorily in the same mist lubrication system in which the Example VI oil was unsatisfactory. That is, the polymeric additives reduced the stray fog to a satisfactory level.

The resulting mist lubricant had the following properties:

Property ASTM Test Result ______________________________________ Viscosity, SUS/100°F. D2161 510 Viscosity, SUS/210°F. D2161 52.0 Viscosity Index D2270 0 Viscosity cST/100°F. D445 110.0 Flash, COC, °F. D92 355 Pour, °F. D97 -10 Gravity, °API D287 20.0 Total Acid No., mgKOH/g D974 1.0 Cu Strip, class (3 hr/212°F) D130 1A Sulfur, % D129 0.65 Timken, lbs. pass D2509 35 Stick-Slip Ratio 0.80 ______________________________________

Such way lubricants, for use as mist oils, can comprise a mineral oil, a stick-slip additive in amount effective to produce a stick-slip ratio of 0.85 or less and a polymeric mist suppressant additive in an amount sufficient to suppress stray fog.

The preferred stick-slip additives include tallow fatty acids, sulfurized sperm oil, and synthetic sperm substitutes (e.g., Caravan 6106 of Cincinnati Milacron Chemicals, Inc.), a cosulfurized blend of lard oil and olefin, neutralized acid phosphates and acid phosphates (Ortholeum 162 or 535).

Especially useful stick-slip additives are the chemical reaction products which can be produced by the action of sulfur or sulfur monochloride on lard oil and olefins (or polyolefin oils). Such cosulfurized compositions are generally useful as a replacement for sulfurized sperm oil and can be obtained by sulfurizing a blend of 90 to 30 parts by weight of lard oil and 10 to 70 parts of an aliphatic olefin containing 6 to 128 carbon atoms (preferably 12-60 carbon atoms). The sulfurization is carried out using elemental sufur. Sulfur monochloride can be used for both sulfurizing and chlorinating simultaneously. The sulfurization can involve cooking at from 330° to 445° F. for 20 minutes to 10 hours followed by blowing with a gas (preferably, at from 125° to 340° F. for 30 minutes to 20 hours) to remove hydrogen sulfide. With sulfur monochloride, the preferred cooking temperature iss in the range of 150°250 (under pressure if desired). The sulfurized oils can contain from 5 to 25 weight percent sulfur as based on the blend of olefin and lard oil (i.e., 5 to 25 parts by weight of sulfur per 100 parts by weight of olefin-lard oil blend).

For example, effective slip-stick ratio reduction. can be achieved by adding to a mineral oil from 0.1-10 wt. % of a composition consisting esentially of a sulfur-containing chemical reaction product of a blend of lard oil and polyisobutylene containing in the range of 12-60 carbon atoms.

One such cosulfurized blend is made as follows:

Twenty-two hundred and sixty ml. of winter strained lard oil were blended with 400 ml. of tetraisobutylene in a 5 L kettle equipped with a vibromixer. The mixture was heated to 250° F. and the vibromixer operated at maximum speed. Sulfur (239 g) was added and the temperature of the mixture was raised to 375° F. for 2 hours. The mixture was then cooled to 200° F. and air was bubbled through the mixture by means of a glass tube at a moderate rate 9below that at which splashing and agitation take place) for 1 hour. The resulting sulfurized oil was analyzed and found to contain 8.23% sulfur. A 10 gram portion of the sulfurized oil was dissolved in 100 g. of a commercially available solvent refined paraffinic lube having a viscosity at 210° F. of 40.45 SUS, an ASTM viscosity index of 104 and containing 12% aromatics (by ASTM D2007). The oil solution remained clear with no separation after being tested at 36° F. overnight and for 1 week at room temperature.

In mist lubricants any mineral oil or blend of mineral oils having a viscosity in the range of 100-3000 SUS at 100° F. can be used; however, the preferred mineral oils comprise solvent refined paraffinic distillate or bright stock, hydrorefined paraffinic distillate or bright stock, hydrocracked paraffinic distillate (which can be stabilized by solvent extraction or by hydrorefining), napthenic distillates (preferably of low napthenic acid content), solvent and/or acid refined naphthenic distillate, and hydrorefined naphthenic distillate and mixtures of two or more of these oils. Especially preferred where there is a possibility of inhalation or ingestion are hydorefined napthenic distillate, stabilized hydrocracked paraffinic distillate and hydrorefined paraffinic distillate (which can be solvent refined before or after the hydrorefining).

The term "hydrocracked paraffinic oil" as used herein is defined as a lube oil viscosity range product of hydrocracking a petroleum charge stock (which can be either paraffinic or napthenic by VGC classification), said hydrocracked product having a VGC below 0.820. That is, hydrocracking (like heavy solvent extraction) can produce oils having a lower VGC (therefore, which are more "paraffinic") than the VGC of the charge. For example, a charge to a hydrocracker can be a distillate fraction of a Lagomedio crude having a viscosity at 100° F. of 191 SUS, API gravity 27.5 and VGC of 0.837 (which would, thus, be classified as "relatively napthenic"). The hydrocracked oil can boil within about the same range as the charge and have a viscosity at 100° F. of 93.5 SUS, API gravity 36.5, and VGC of 0.791 (or "paraffinic" by class). After dewaxing the ASTM-VI of the product can be 120. Such a hydrocracked oil, having a "paraffinic" VGC is included within the term "hydrocracked paraffinic oil."

TEST PROCEDURE

The "Norgren" test apparatus, as referred to herein, is illustrated schematically in the accompanying FIG. 3. It comprises a gas regulater 1, gas filter 2, air control valve (including a flow gauge) 3, timer 4, air heater 5, primary pressure gauge 5, thermometers 7, and 8, the C. A. Norgren mist generator (9), oil heater 10, sump 11, manifold pressure gauge 12, manifold assembly 13, reclassifier nozzles 14 and reclassifier collection cup 15.

The accompanying FIG. 4 illustrates the three main types of nozzle (mist, spray and condensing). In all of the work reported herein, the "mist" nozzle was used.

The following is the test procedure used with the Norgren test apparatus.

1. Weigh all oil-containing or collecting components (9, 11, 13, 14, 15).

2. Fill sump with test oil.

3. Weigh sump again to calculate oil weight.

4. Assemble sump and turn-on air to 23.0 p.s.i.g. (gauge 6). Flow rate should be approx. 5.35 SCFM air.

5. Run for about 1 hour, bringing oil and air to desired temperature.

6. Disassemble and weigh all components.

7. Repeat steps 3-6 as desired to obtain test dats (the first hour run results are usually discounted).

8. Calculations

A. output is oil weight taken from generator divided by total SCFM of air through, generally reported as (gm/SCF.hr).

B manifold losses are weight of oil collected in sump and manifold (generally expressed as % of total output).

C. reclassification is weight of oil collected in cup 15, expressed as % of total output (or, by calculation, as oz/hr/100 B.I. or as drops per CF per minute (where a drop is 0.071 gram).

D. stray fog is the oil taken from the generator minus manifold losses and reclassification, generally reported as % stray fog 9100-B-C) or as grams/hour.

In this test procedure the important parameters are time, air pressure and flow rate, manifold pressure, air and oil temperatures, and type and number of reclassifiers (each) nozzle being called a reclassifier). In the testing referred to herein, 10 mist nozzles were used.

The two key characteristics of a mist lubricant are the amount of product getting to the bearing to satisfy the lubrication requirements, and the amount of stray fog going to the atmosphere. In general, no visible stray fog should be produced by the oil during use. In general, the performance of a misting lubricant can involve four factors (the first two being the more important in the Norgren tester):

1. Stray Fog is a portion of mist output which does not reclassify at lubrication point

2. Reclassification - is the percent of oil output which recombines to become usable lubricant

3. Mist Output - is the amount of mist taken from reservoir per cubic foot of air (this is principally a function of oil viscosity and temperature)

4. Manifold Loss - is the percent of mist output that is lost in the system's plumbing. In the testing referred to herein, this loss should be less than 60%; however, in commercial operations this loss is less than 10%.

Since vicosity has an effect on misting, the following table compares properties of three viscosity grades of the mist lubricant of Example V (the differing viscosities being due to differing base oils).

______________________________________ Oil A Oil B Oil C ______________________________________ Viscosity, SUS/100°F. 111 340 1520 Test Temperature, °F. 77 85 120 Reclassifier Output Gms. oil/hr./SCFM 20.90 11.56 11.0 Fl. oz./hrs./100 bearing in. 2.06 1.12 1.0 Manifold Loss, % Output 49.3 45.9 47.4 Reclassified, % Output 45.0 51.0 48.8 Stray Fog, % Output 5.7 3.1 3.8 ______________________________________

The oil of Example V is especially useful as a mist lubricant since it possesses a good combination of misting characteristics and lubrication properties. The misting properties include low stray fog, high constant oil-output (low change with temperature) and low manifold loss. the lubrication properties include good oxidation stability, foam resistance, good demulsibility, rust and corrosion resistance, good load carrying ability and, for waxy lubrication, low static coefficient of friction. Oxidation stability and foam resistance are of prime importance during the process of mist lubrication. Regarding oxidation resistance, the following test results show the excellent oxidation stability of the Example V oil in comparison with a commercially available mist oil. The test was a modified (no water) D943 oxidation test run for 1000 hours with copper and iron catalysts, and air at 203° F.

______________________________________ Commercial Example Mist Oil B V OIL ______________________________________ Viscosity Increase, 100°F., % 414 2.3 Total Acid Number, mgKOH/g, final 3.3 1.2 Pentane Insolubles, % 0.68 0.07 Visual Sludge Heavy Light ______________________________________

Foam resistance and demulsibility are also important if the charge oil becomes contaminated with water. The Example V oil has excellent foam resistance and demulsibility both of which are quite poor for the commercial mist oil B, as shown by the following data:

Commercial Mist Oil Example V Oil ______________________________________ Foam Test, D892 ml. Tendency/Stability Sequence I 520/30 5/0 Sequence II 290/0 5/0 Sequence III 330/15 5/0 Demulsibility, 180°F, D2711 Free Water, ml. 58.0 85.0 Centrifuged Water, ml. 13.0 2.5 Total Water, ml. 71.0 87.5 Cuff, ml. 5.0 0.25 ______________________________________

Once the oil has reclassified at the point of lubrication, it must be a good lubricant and rust preventive. The ability of the Example V oil to lubricate and protect against rust in conventional tests is illustrated by the ASTM D665 B test, which the Example V oil passes and by the ASTM D130 corrosion test (3 hours/212° F.) in which the Example V oil rates "No. 1."

The lubricity of the Example V type oil under high unit loads for short time periods (E.P.) can be tested by the Timken Tester, and under normal loads for a long time (antiwear) by the 4-Ball Wear Tester.

The data for Example V oil are shown below in comparison with a commercial antiwear E.P. Mist oil. Both provided excellent performance.

______________________________________ Competitive Example Mist Oil V OIL ______________________________________ Timken Test, lbs/pass 60 60 4-Ball Wear Test, scar diameter/mm 20 Kg., 1800 RPM, 130°F, 1 hour .40 .40 40 Kg., 1800 ROM, 130°F, 1 hour .45 .45 ______________________________________

The suitability of the Example V oil for feeding slide ways is shown by measurements using the Cincinnati Milling Machine Test procedure which has tentative approval by ASTM D2877. A comparison of the Example Voil coefficient of friction with the commercial mist oil follows (both performed well).

______________________________________ Competitive Example Mist Oil B V Oil ______________________________________ Stick-Slip Friction Test Coefficient of Static Friction (μ _s ) 0.108 0.103 Coefficient of Kinetic Friction (μ _k ) 0.128 0.124 Ratio (μs/μk) 0.85 0.83 ______________________________________

Note that static friction is reduced below kinetic (moving) friction which eliminates stick-slip and provides smooth machine start up.

In mist lubrication systems, the oil output from the mist generator is transported in an air stream as mist to the lubrication point where it is reclassified or liquified.

Optimum mist droplets vary in particle size from 0.5 to 2.0 microns. These small droplets are required at low air velocities of approximately 20 feet per second or less to maintain stable non-condensing mists. Any particles above 2.0 microns are knocked out by a baffle and are returned to the reservoir. Extremely small particles (below 0.5 micron) can be stable at high air velocities but condensation is difficult, and an objectionable fog can fill the atmosphere around the equipment.

Reclassified oil percent is the amount of oil output which recombines to become usable lubricant. Oil output is the grams of oil taken from the reservoir per cubic foot of air. The amount of mist generated and reclassified can be affected by pressure and temperature. The mist output increases with feed air pressure. However, a critical balance must be maintained because too high a feed air pressure to the generator can pick up too much oil and cause increased dropout (wet out) in the manifold line. Oil sump and air heaters can be used to facilitate misting of viscous products. The viscosity grade is usually determined by the lubrication requirements. If the grade is too heavy for optimum misting, temperature should be adjusted to thin it to the proper misting viscosity. Heating is recommended when an oil 500 SUS at 100° F. or above is used, because it has been determined that to obtain satisfactory lubrication of one fluid ounce per hour for 100 bearing inches, the viscosity should preferably be below 900 seconds at application temperature.

When the customer uses mist oils of the Example V type (e.g., high VI, paraffinic base oil) he should follow the table below:

Generator Oil Viscosity/100°F. Temp. °F. Viscosity ______________________________________ 500 85 800 1000 105 850 1500 120 800 2000 130 800 2500 140 800 ______________________________________

The portion of the oil output that is not reclassified at the lubrication points or lost as stray fog represents "Wet out" in the mist delivery plumbing and is called manifold loss. Stray fog is the portion of the oil output which does not reclassify at the lubrication point. It usually vents at the lubrication point into the room housing the machinery. The polymer level should be adjusted so there is no visible stray fog (e.g., less than 10 g/hr in Norgrentest).

Reclassifier nozzles are designed to provide turbulence which promotes reclassification. Three different types of reclassifying nozzles are shown in FIG. 4. They are:

a. Mist nozzle - for operations such as high-speed ball and roller bearings where the nozzle simply directs the oil/air mixture to the bearing which is moving fast enough to reclassify the oil.

b. Spray nozzle - has a more restricted orifice flow area and a longer passageway which results in a semi-wet spray. This nozzle is used when lubricating moderate-speed gears, chains, and antifriction bearings.

c. Condensing nozzle - tiny droplets are formed when the mist hits a baffle in the nozzle and drop into or onto the mechanism to be lubricated. This nozzle is used for low-speed bearings, ways, and slides.

Various combinations of these nozzles can be used with a single mist system. It should be understood that none of them is 100% efficient and some quantity of oil escapes to the atmosphere as "stray fog."

Mist lubricators are very sensitive and require precise adjustment. Based on the type of system involved, some or all of the following adjustments may have to be considered for optimum operation:

1. Feed-air pressure - increasing the air pressure increases the amount of oil mist generated.

2. Feed-air temperature - increasing this also will increase the amount of oil mist generated.

3. Oil-sump temperature - can be used to control the oil viscosity to optimize misting.

4. Oil suction tube control - the amount of oil atomized at a given temperature, pressure, and oil viscosity is controlled by the size of the suction tube.

These controls affect the mist output in a predictable fashion and should be set to minimize manifold wet-out and stray fog. Selection of oil viscosity should be based on the lubrication requirement, and adjusted for optimum misting by changing temperatures and, if necessary, pressure.

GLOSSARY OF TERMS

Bearing Inch:

Is a unit of measurement used for selecting the appropriate capacity misting unit. The shaft diameter measurement in inches represents "bearing inch" rating for a single row antifriction bearing.

CFM (SCFM):

Cubic feet per minute of air or mist.

Fluid Ounce (Fl. oz.):

One fluid ounce (Fl. oz.); 1.805 cu. in.

Manifold:

Mist distribution piping.

Manifold Pressure:

Gauge pressure of mist in manifold.

Mist:

Oil-mist is an aerosol dispersion of air and oil particles ranging in size from one-half micron diameter to approximately 8 micron diameter.

Mist Fitting:

An application fitting that meters oil-mist with minimum coversion to oil spray or droplets,

Mist Velocity:

Feet per second (FPS); maximum recommended mist velocity is 24 FPS. Prelubrication

Since oil-mist is a system which continuously supplies make-up oil, all machine elements must be pre-oiled before initial machine operation

Regulated Air Pressure:

Controlled gauge pressure applied to the oil-mist generating nozzle. Pressure drop across the nozzle equals regulated air pressure minus the manifold pressure in psi.

Following is a table showing the typical properties of mist lubricants of the Example V type (the polymer can either be acrylic or a mixture of acrylic polyolefin).

________________________________________________________ __________________ TYPICAL PROPERTIES OF MIST LUBRICANTS* ____________________________________________________________ ______________ Property Viscosity, SUS/100°F. D2161 97.0 205 301 509 1031 1520 2065 2550 Viscosity, SUS/210°F D2161 41.6 49.8 57.5 68.4 97.0 119 141 162 Viscosity Index D2270 174 137 138 116 109 104 102 102 Viscosity, cSt/100°F D445 19.8 44.0 64.8 109.8 222.9 328.3 445.9 551.1 Viscosity, cSt/210°F D445 4.66 7.20 9.50 12.54 19.64 24.7 29.8 34.2 Flash, COC, °F D92 355 395 410 420 440 460 470 500 Fire, COC, °F D92 385 420 435 450 470 490 500 525 Pour, °F D97 -25 -40 -40 -25 -15 -15 -10 -10 Color D1500 4.5 5.0 6.0 6.0 6.0 6.5 6.5 6.5 Gravity, °API D287 33.4 31.7 30.1 29.3 28.5 27.5 26.9 27.2 Pounds per Gallon D1250 7.14 7.63 7.24 7.30 7.37 7.39 7.42 7.42 Specific Gravity D1250 0.858 0.916 0.869 0.877 0.886 0.888 0.890 0.892 Total Acid No., mgKOH/g D664 0.65 0.65 0.65 0.65 0.65 0.65 0.65 0.65 Copper Strip, class (3 hr/212°F) D130 1A 1A 1A 1A 1A 1A 1A 1A Foam, Tend/Stab D892 Sequence I, ml 5/0 5/0 5/0 5/0 5/0 5/0 10/0 5/0 Sequence II, ml 20/0 10/0 5/0 5/0 5/0 5/0 10/0 10/0 Sequence III, ml 5/0 5/0 5/0 5/0 5/0 5/0 10/0 5/0 Rusting, Syn. Sea Water D665B Pass Pass Pass Pass Pass Pass Pass Pass Timken, lb Fed. 6505 55 60 60 60 60 60 60 60 Stick-slip Ratio 0.82 0.80 -- 0.82 -- -- -- 0.82 Demulsibility, 180°F D2711 Free Water, ml -- -- 83 85 -- 83 82 80 Centrifuged Water, ml -- -- 2.5 2.5 -- 6.0 8.0 9.0 Cuff, ml -- -- 0.25 0.25 -- 0.60 0.50 -- Oxidation Stability D943 Mod. ¹ Vis Inc at 210°F, % -- -- -- -- 10.0 -- -- -- Total Acid No. Inc., mgKOH/g -- -- -- -- 0.83 -- -- -- Pentane Insolubles, % -- -- -- -- 0.02 -- -- -- Visual Sludge -- -- -- -- V.Light -- -- -- ____________________________________________________________ ______________