US3121058A - Lubricant composition - Google Patents

Description

United States Patent 3,121,058 LUBRHZANT CGMPOSITIGN Manley Kjonaas, Hammond, and David W. Young,

Hoinewood, Hi, assignors to Sinclair Refining 6on1- pany, New York, N.Y., a corperation of Maine No Drawing. Filed 0st. 3, 1960, Ser. No. 59,862 (Jlaims. (Cl. 252-427) This invention relates to novel synthetic lubricating oil compositions. More specifically, the present invention is concerned with synthetic oils of lubricating viscosity consisting essentially of base oil having incorporated therein small amounts of glycol titanate and camphoric acid.

The demand for synthetic lubricants is ever increasing in view of, among other things, their low pour point, high viscosity index and low volatility for a given viscosity. The demand is particularly due to the present widespread use of turbojet and turboprop engines for military and commercial aircraft. In these useslubricants having mineral oil bases and containing additives to impart desired characteristics such as viscosity index improvement and extreme pressure properties, may not be satisfactory since these compositions are sources of deposits which can interfere with proper engine operation. Even though most synthetic lubricants have high viscosity indices, low volatilities and low pour points, the latter affording good low temperature starting characteristics, at least certain of these oils fail to meet all of the required specifications.

Specifications relating to synthetic lubricating oils have been promulgated which set minimum requirements for load-carrying capacity, lead corosion, storage stability, and resistance to oxidation, among others. These minimum requirements must be met by the synthetic lubricant in order to be acceptable for use in,-for example, certain aircraft. It has been found that glycol titanates are excellent load-carrying agents (as measured by the Ryder gear test) but in order to be fully effective a small amount of free dibasic acid must be present. The free dibasic acid also assists in protecting the lubricant against lead corrosion as measured by the SOD lead corrosion test. The amount of free dibasic acid is generally carefully controlled for an excess of free dibasic acid may cause a decrease in oxidation resistance resulting in excessive deposits as measured by the panel coking test.

However, dibasic acids when added to a glycol titanatecontaining base oil often provide a synthetic lubricant composition which does not exhibit the desired storage stability as measured by the SOD storage stability test. In other words, upon storage the lubricants become hazy, accompanied by the formation of a white precipitate. This insoluble precipitate formation has been found to be due to interaction of the glycol titanate additive and the free dibasic acid. Certain dibasic acids when added to a glycol titanate containing lubricants do provide compositions that pass the storage stability test but fail to meet one or more of the other aforementioned specifications.

It has now been discovered that a synthetic lubricating oil having incorporated therein a minor amount of a glycol titanate and camphoric acid provides a lubricant composition having a high load-carrying capacity that age and at the same time meets specifications with respect to lead corrosion and oxidation resistance. The titanate and camphoric acid are present in minor amounts effective to impart extreme pressure or load-carrying properties to the base oil. The camphoric acid can be for instance, d-camphoric acid, l-camphoric acid, dl-camphoric acid, their mixtures or their substituted forms.

The glycol titanate used in this invention may be liquid or solid but if it is a polymer it is normally solid and its molecular weight will frequently be from about 800 to 3000 and preferably from about 1000 to 1800 but the molecular weight may even be as high as 5000 to 20,000 or more. The glycol titanate is a base oil-compatible chelate complex which is monomeric or polymeric does not result in haze or precipitate formation on storin form and can contain about 0.5 to 4, preferably about 2 to 4 moles of glycol residue per atom of titanium. Although the structure of the polymer is uncertain, it is theorized that it maintains the claw structure of the chelate complex monomer or partial polymer from which it is made. This chelate is characterized by a coordinate valence bond between an'oxygen and a titanium atom. Such organo-titanium chelates are commercially available or they may be easily manufactured by the reaction of a titanium tetraester such as a tetraalkyl titanate or chloroalkyl titanate and a glycol containing from 2 to about 20 or 24 carbon atoms or more, preferably 2 to 12, or probably even by direct reaction between a glycol and ortho titanic acid. The glycols may be unsubstituted or substituted as with halogen or another hydroxy radical. The production of tetraalkyl titanates as well as organo-titanium chelates are described in US. Patent 2,643,262. Tetraalkyl titanates can he prepared by the esterification of'ortho titanic acid with an alcohol. Suitable titanium esters for conversion to glycol titanate chelate complexes are alkyl titanates, the alkyl radical of which contains 2 to 20 or 24 carbon atoms, preferably 2 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl 2-ethylhexyl, dodecyl, cyclohexyl and ethoxyethyl tetraesters; aryl tetraesters such as phenyl and beta-naphthyl tetratitanates; aralkyl esters such as benzyl tetratitanates and mixed esters including diethyl, diphenyl titanate.

The preferred glycol titanate chelate complexes are those prepared through the reaction of a titanium tetraester with a glycol of the 1,3-diol type. Preferably these glycols are 1,3-diorgano hydrocarbon substituted materials which have the formula:

The diorgano radicals, that is the R and R of the glycol formula, can be alkyl, aryl or mixed, and if desired, be substituted as with halogen, for instance chlorine. These glycols or others used in making the titanates may contain 2 to 24 carbon atoms. Among the specific glycols which can be employed are 2-ethyl-1,3-hexanediol, 2- propyl-1,3-heptanediol, 2-methyl-1,3-pentanediol, 2-butyl- 1,3-butanediol, 2,4-diphenyl-1,3-butanediol, and 2,4-dimesityl-l,3-butanediol. The R and R group should be substantially inert under the conditions to which the lubricant composition is to be exposed. Generally, the preferred glycols contain from about 5 to 12 carbon atoms, for instance an octylene glycol; however, if de- 3 sired, they could contain a greater number of carbon atoms.

Usually the mere combination of a titanium tetraester and a glycol initiates an exothermic reaction, although if desired, heat can be employed to speed the alcoholysis. The glycol is reacted in the proportions of A2 part glycol to one part titanium ester to four parts glycol to one part titanium ester. The initial reaction may proceed only to the monomer stage or continue to a polymer product directly. The glycol titanate chelate complex can be polymerized through heat, or through water addition and heating. There is no particular critical limitation on the extent of either, except, of course, the temperature should not be so high as to decompose the desired reaction products. Ordinarily, the polymerization temperature will be above about 25 C. and preferably at least about 40 C. In the absence of Water, the monomer may be dissolved in a solvent and heated. It may be desirable in this alternative to use a vacuum, say about to millimeters of mercury, and a temperature of about 130 to 170 C. to remove the solvent while forming the polymer. Other conditions of temperature and pressure can be employed. Among the suitable inert solvents which can be employed are cyclohexane, n-butane, benzene, etc. If water is present during polymerization at least one part of Water per part of the original titanium chelate is usually employed, with 2 to 20 parts of water being used most advantageously. At the end of the reaction, alcohol and water can be boiled off or otherwise removed. The length of time the heating is conducted can be varied widely and is not critical, and apparently during polymerization non-chelated groups of the titanium reactant are hydrolyzed from the molecule.

These reaction products are relatively water-insensitive, is. they do not readily revert to TiO when brought into contact with water. This is a distinct advantage in commercial application since such a compound will not require anhydrous transportation and storage conditions. The glycol titanates are compatible; that is, soluble, miscible or dispersible with the other ingredients of the lubricant composition. Frequently the titanate will be added to the composition of the invention as a solution in an inert diluent. One commercially available chelate is DST-41. This is a composition containing 4 moles of octylene glycol (2-ethylhexane-diol-1,3) to each mole of titanium dispersed in 40% by weight of butanol. This chelate is a liquid which is insoluble in Water but soluble in alcohol and hydrocarbons. Other chelates containing varying proportions of octylene glycol with titanium are available in the OGT series and these are also suitable. These products may not be distinct compounds since they are not distillable or crystallizable and they appear to be partially polymerized.

The composition of the present invention contains a minor amount of the titanium additive agent to enhance the load-carrying capacity of the base oil. Generally, the final lube composition will contain from about 0.001 to 5 Weight percent of the titanium additive, preferably about 0.1 to 2 Weight percent. More than 5 percent can be used but there does not appear to be any necessity for this. The actual amount employed may be dependent upon the degree of improvement desired and upon factors such as the character of the base oil and the other materials which may be added to the composition.

The camphoric acid agent of the present invention is present in a minor amount sufficient to provide increased load-carrying capacity and lead corrosion resistance to the composition. Generally, at least about 0.005 Weight percent of the camphoric acid is employed, preferably about 0.01 to 0.1 weight percent. There seems to be little if any beneit to be derived from using more than about 1% of the acid. The preferred camphoric acid is dcamphoric acid.

The compositions of the present invention can also contain additional agents such as anti-oxidants, anti-foaming l additives, corrosion inhibitors, Vi improvers, other extreme pressure agents, thickeners and other agents added to give desired properties, as long as they do not unduly detrimentally aiiect the final composition.

The lubricant composition of this invention includes as the major component a base oil which is an ester of lubricating viscosity which may be, for instance, a simple ester or compounds having multiple ester groups such as complex esters, polyesters, or diesters. firese esters are made from monoand polyhydroxy aliphatic alcohols and aliphatic carboxylic acids, both frequently of about 4 to 12 carbon atoms; aliphatic including cycloaliphatic. The term alkanol is used to designate the monoand polyhydroxyalcohols while the term alkane carboxylic acid denotes the monoand polycarboxylic acids. The reaction product of a monohydroxy alcohol and a monocarboxylic acid is usually considered to be a simple ester. A diester is usually considered to be the reaction product of 1 mole of a carboxylic acid, say of 6 to 10 carbon atoms, with 2 moles of a monohydric alcohol or of 1 mole of a glycol of 4 to 10 carbon atoms with two moles of a monocarboxylic acid of 4 to 10 carbon atoms. The diesters frequently contain from 20 to 40 carbon atoms. One complex ester is of the type XY-ZYX in which X represents a monohydric alcohol residue, Y represents a dicarboxylic acid residue and Z represents a glycol residue and the linkages are ester linkages. Those esters, wherein Z represents a monoacid residue, Y represents a glycol residue and Z represents a dibasic acid residue are also considered to be complex esters. The complex esters often have 30 to 50 carbon atoms. Polyesters, or polyester bright stocks? can be prepared by direct esterlfication of dibasic acids with glycols in about equimolar quantities. The polyesterification reaction is usually continued until the product has a kinematic viscosity from about 15 to 200 centistokes at 210 F., and preferably 40 to centistokes at 210 F.

Although each of these products in itself is useful as a lubricant, they are particularly useful when added or blended with each other in synthetic lubricant compositions. These esters and blends have been found to be especially adaptable to the conditions to which turbine engines are exposed, since they can be formulated to give a desirable combination of high flash point, low pour point, and high viscosity at elevated temperatures, and need contain no additives which might leave a residue upon volatilization. In addition, many complex esters have shown good stability to shear. Natural esters, suchas castor oil may also be included in the blends, as may be up to about 1 percent or more by weight of a foam inhibitor such a methyl silicone polymer or other additives to provide a particular characteristic, for instance, extreme pressure or load-carrying agents, corrosion inhibitors, etc, can be added.

Typical synthetic lubricants may be formulated essentially from a major amount (about 60-85%) of a complex ester and a minor amount (about 15-40%) of a diester, by stirring together a quantity of diester and complex ester at an elevated temperature, altering the proportions of each component until the desired viscosity is reached. Polyesters can be employed to thicken diester base stocks to increase the load-carrying capacity of the base diester oil. The polyester will generally not comprise more than about 50 weight percent of the blend, preferably about 20 to 35 weight percent. Usually the amount of the polyester employed in any blend would be at least about 5 percent, and the majority of the lubricant is a diester. Other polymers such as Acryloids may be added as thickeners to the esters, generally the simple esters such as the above diesters, to obtain a base oil of desired viscosity. The Acryloids are polymers of mixed C to C esters of methacrylic acid having 10,000 to 20,000 molecular weight. Advantageously the final lubricating oil composition would have a maximum viscosity at 40 F. of about 13,000 centistokes and a minimum viscosity of about 7.5 centistokes at 210 F.

The monohydric alcohols employed in these esters usually contain less than about 20 carbon atoms and are generally aliphatic. Preferably the alcohol contains up to about 12 carbon atoms. Useful aliphatic alcohols include butyl, hexyl, methyl, isooctyl and dodecyl alcohols, C oxo alcohols and octadecyl alcohols. C to C branched chain primary alcohols are frequently used to improve the low temperature viscosity of the finished lubricant composition. Alcohols such as n-decanol, 2- ethylhexano oxo alcohols, prepared by the reaction of carbon monoxide and hydrogen upon the olefins obtainable from petroleum products such as diisobutylene and C7 olefins, ether alcohols such as butyl carbitol, tripropylene glycol mono-isopropyl ether, dipropylene glycol mono-isopropyl ether, and products such as Tergitol 3A3, which has the formula C H O(CH OH O) N, are suitable alcohols for use to produce the desired lubricant. If the alcohol has no hydrogens on the beta carbon atoms, it is nee-structured; and esters of such alcohols are often preferred. In particular, the nee-C alcohol2,2,4-trimethyl-pentanol-1-gives lubricating diesters or complex esters suitable for blending with diesters to produce lubricants which meet stringent viscosity requirements. lsooctanol and isodecanol are alcohol mixtures made by the x0 process from C -C copolymer heptenes. The out which makes up isooctanol usually contains about 17% 3,4-dimethylhexanol; 29% 3,5-dimethy-lhexanol; 25% 4,5-dimethylhexanol; 1.4% 5,5-dimethylhexanol; 16% of a mixture of B-methylheptanol and 5-ethylheptanol; 2.3% 4-ethylhexanol; 4.3% ot-al-kyl alkanols and 5% other materials.

Generally, the glycols contain from about 4 to 12 car- ,bon atoms; however, if desired they could contain a greater number. Among the specific glycols which can be employed are 2-cthyl-l,3-hexanediol, 2-propyl-3,3 heptanediol, Z-methyl-l,3-pentanediol, 2-butyl-1,3-butanediol, 2,4-diphenyl-1,3-butanediol, and 2,4-dimesityl-1,3- butanediol. In addition to these glycols, other glycols may be used, for instance, where the alkylene radical contains Z to 4 carbon atoms such as diethylene glycol, dipropylene glycol and other glycols up to 1000 to 2000 molecular weight. The most popular glycols for the manufacture of ester lubricants appear to be polypropylene glycols having a molecular weight of about 100- 300 and 2-ethyl hexanediol. The 2,2-dimethyl glycols, such as neopentyl glycol have been shown to impart heat stability to the final blends. Minor amounts of other glycols or other materials can be present as long as the desired properties of the product are not unduly deleteriously affected.

Aside from glycols, the esters may be made from polyhydric alcohols of more than two hydroxyl groups, e.g. triand tetrahydroxy aliphatic alcohols having about 4 to 12 carbon atoms, preferably about 5 to 8 carbon atoms; for instance pentaerythritol, trimethylolpropane and the like. Particularly suitable ester base oils are formed when these alcohols are reacted with monocarboxylic acids having about 4 to 12 carbon atoms, preferably 4 to 9 carbon atoms. It is preferred that the reaction be conducted so as to substantially completely esterify the acids.

One group of monocarboxylic acids includes those of 8 to 24 carbon atoms such as stearic, lauric, etc. The carboxylic acids employed in making ester lubricants will often contain from about 4 to 12 carbon atoms. Suitable acids are described in U.S. Patent No. 2,575,195 and include the aliphatic dibasic acids of branched or straight chain structures which are saturated or unsaturated. The preferred acids are the saturated aliphatic carboxylic acids containing not more than about 12 carbon atoms, and mixtures of these acids. Such acids include succinic, adipic, suberic, azelaic and sebacic acids and isosebacic acid which is a mixture of a-ethyl suberic acid, aged-diethyl adipic acid and seb-acic acid. This composite of yl, is a representative complex ester.

acids is attractive from the viewpoint of economy and availability since it is made from petroleum hydrocarbons rather than the natural oils and fats which are used in the manufacture of many other dicarboxylic acids, which natural oils and fats are frequently in short supply. The preferred dibasic acids are sebacic and azelaic or mixtures thereof. Minor amounts of adipic used with a major amount of sebacic may also be used with advantage.

Various useful ester base oils are disclosed in US. Patents Nos. 2,499,983; 2,499,984; 2,575,195; 2,575,196; 2,703,811; 2,705,724 and 2,723,286. Generally, the synthetic base oils consist essentially of carbon, hydrogen and oxygen, i.e. the essential nuclear chemical structure is formed by these elements alone. However, these oils may be substituted with other elements such as halogens, e.g. chlorine and fluorine. Some representative components of ester lubricants are ethyl palmitate, ethyl stearate, di-(Z-ethylhexyl) sebacate, ethylene glycol dilaurate, di (Z-ethylhexyl) phthalate, di-(1,3-methyl butyl) adipate, di-(Z-ethyl butyl) adipate, di-(l-etnyl propyl) adipate, diethyl oxylate, glycerol tri-n-acetate, di-cyclohexyl adipate, di-(undecyl) sebacate, tetraethylene glycol di-(2-ethylene hexoate), di-Cellosolve phthalate, butyl phthallyl butyl glycolate, di-n-hexyl fumarate polymer, dibenzyl sebacate, and diethylene glycol bis-(Z-n-butoxy ethyl carbonate). Z-ethylhexyl-adipate-neopentyl glyoly-adipate-Z-ethylhex- Generally, these synthetic ester lubricants have a viscosity ranging from light to heavy oils, e.g. about 50 SUS at F. to 250 SUS at 210 F., and preferably 30 to SUS at 210 F.

The esters are manufactured, in general, by more reaction of the alcoholic and acidic constituents, although simple esters may be converted to longer chain com ponents by transesterification. The constituents, in the proportions suitable for giving the desired ester, are reacted preferably in the presence of a catalyst and solvent or water entraining agent to insure maintenance of the liquid state during the reaction. Aromatic hydrocarbons such as xylene or toluene have proven satisfactory as solvents. The choice of solvent imluences the choice of temperature at which the esterification is conducted; for instance, when toluene is used, a temperature of 140 C. is recommended; with xylene, temperatures up to about 195 C. may be used. To provide a better reaction rate an acid esterification catalyst is often used. Many of these catalysts are known and include, for instance, HCl, H 30 NaHSO aliphatic and aromatic sulfonic acids, phosphoric acid, hydrobromic acid, HF and dihydroxyfluoboric acid. Other catalysts are thionyl chloride, boron triliuoride and silicon tetrafluo-ride. Titanium esters also make valuable esterification and transesterification catalysts.

In a preferred reaction, about 0.5 to about 1 weight percent, or advantageously, 0.2 to 0.5% of the catalyst is used with a xylene solvent at a temperature of to 200 C. While refluxing water. The temperatures of the reaction must be sufficient to remove the water from the esterification mass as it is formed. This temperature is usually at least about 140 C. but not so high as to decompose the wanted product. The highest temperature needed for the reaction will probably be about 200 0, preferably not over about C. The pressure is conveniently about atmospheric. Although reduced pressure or superatmospheric pressure could be utilized, there is usually no necessity to use reduced pressures, as the temperatures required at atmospheric pressure to remove the water form-ed do not usually unduly degrade the product.

When reacting glycols with dibasic acids to produce a polyester, it is preferred to continue the reaction with concomitant boiling cit of water from the reaction mixture until the polyester product has a kinematic vis cosity of about 15 to 200 centistokes at 210 F, preferably about 40 to 130 centistokes. When this point has been reached, the polymerization can be stopped, for instance,

'with weight percent of propylene oxide. it is also conventional to subject the ester to filtration to remove insoluble materials. After this the product may be subjected to a reduced pressure distillation or stripping at 100 to 200 C. to remove volatile materials, such as Water, the solvent and light ends.

The following exmnples are included to further describe the present invention.

EXAMPLE I A glycol titanate polymer was prepared as follows:

2-ethyl-1,3-hexanediol and tetra-n-butyl titanate were reacted as disclosed in the aforesaid Patent 2,643,262, to' produce a chelated compound containing four moles of octylene glycol for each mole of titanium. 164 pounds of a solution of this product containing 40% butanol were weighed into a stainless steel Pfaudler kettle. While stirring vigorously, 210 pounds of tap water were added. The stirred mixture of water and precipitated polymer were heated to 170 F. over a twenty-minute period. When the mixture reached 170 F, the agitation was stopped, and the mixture was allowed to settle 1 hour. The upper organic layer and water were siphoned oil the wet polymeric white solid. A second charge of tap water, 210 pounds, was added to the kettle, While agitating vigorously, and the mixture was heated to 170 F. The agitation was stopped, and the mixture was allowed to settle two hours. The bulk of the water was siphoned off the polymer; the last part of the water was drained through the wet granular polymer to the bottom valve on the kettle and discarded. 147 pounds of Plexol 201 (di- [Z-ethylhexyl] sebacate) were then charged to the stirred kettle, and the contents heated to 180 F., at which temperaure the polymer dissolved. The agitation was stopped, and the solution settled for 30 minutes. The lower water layer was drawn oil, and discarded. At this point the organic layer was almost clear, except for a slight water haze. The organic layer was dehydrated. by heating to 250 F. and cooled to 80 F. Product yield was 190 pounds of clear yellow liquid containing weight percent polymer and having the following analysis.

Kinematic viscosity:

A number of blends containing 1.0% of the above titanium polymer concentrate, various amounts of several dibasic acids, 0.5% of phenothiazine as an antioxidant and 0.0005% of a polysilicon anti-foam agent in di(2- ethylhexyl) sebacate were prepared as follows:

Plexol 201 (di-[Z-ethylhexyl] sebacate) was charged to a kettle along with the dibasic acid, an antioxidant (phenothiazine) and an anti-foam agent and the mixture heated to 225 F. with mixing. The mixture was allowed to cool to room temperature, and then 1.0 weight percent of the above titanate polymer concentrate was blended into the composition.

The blends thus prepared were subjected to the SOD storage stability test which comprises storing samples of the blends in 4-ounce bottles and examining the bottles frequently for the formation of haze or precipitate. The blend compositions and results of the test are shown in Table 1.

Table I Percent Time to Form Haze Free Dibasic Acid in Blend Free or Precipitate Acid 0. 01 5 Weeks. 0.0125 4 Weeks. 0.015 Do. 0.02 Less than 12 Days. 0.01 6 Weeks. 0.0125 Less than 2 Weeks. 0. 015 Do. 0. 02 D0. 0.01 Do. 0. 0125 Do. 0.15 Do. 0. 02 Do. 0.01 Over 11 Weeks. 0.015 0 Weeks. 0.02 Clear at 8 Weeks. 0.03 Do. Tore 0.01 4 Days.

Do 0.02 Clear at 7 Weeks. D 0. 03 Do. Isopht 0.01 Clear at 11 Weeks.

D 0. 02 8 Weeks. 0. 03 5 Weeks. 0.01 Clear at 10 Weeks. 0. 01.25 Do. 0.015 Do. Do 0. ()2 Do.

The data of Table I show that only the blends containing o-phthalic, isophthalic, terephthalic and d-camphoric acid were stable in the storage stability test at desired concentrations. These latter blends were then subjected to the SOD lead corrosion and the panel coke test. The SOD lead corrosion test comprising subjecting a lead strip to an aerated blend for 1 hour at 325 F. in the presence of a copper strip catalyst and measuring the weight of the lead loss. The weight loss must not be greater than 6.0 milligrams per square centimeter of surface. The panel coke test comprises splashing lubricanton a test metal panel at 600 F. for 8 hours and measuring the weight of decomposition products accumulated on the panel.

The blends and results of the tests are shown in Table II.

Table I1 Free Dibasic Acid Present in Blend SOD Lead Corrosion Wt. Panel Coke Loss, rug/per Test (Max. in. (Max. Allowed: Acld Used Wt. Per- Allowod= mg.)

cent -6.0)

d-Camphoric 0.015 0. 46 D0 0.015 0. 44 0. 02 -7. 66 0.03 -6. 92 0. 05 11.62 0.01 l5. 57 0.02 -16.90 0. 012 -0. 13 0.02 -0. 289 0.02 -2. 37 0.03 -0. 178

The data of Table II shows that o-phthalic and terephthalic acid blends fa led the SOD lead corrosion test. Isophthalic acid blend failed the panel coke tests. Thus, of all the acid blends tested only the d-camphoric acid lends passed all three tests.

EXAMPLE II To demonstrate that the d-camphoric acid blends provide a lubricant composition having a high load-carrying capacity, blends prepared in accordance with the method of Example I, containing various amounts of d-camphoric acid [1.0% of the titanium polymer of Example I in di- (Z-ethylhexyl) sebacate], were subjected to the Ryder gear test. The Ryder gear test involves subjecting the lubricant to a Ryder gear test machine at 10,000 r.p.m.i rpm.

For comparative purposes, a similar blend containing .Ol% sebacic acid was also subjected to the Ryder gear test. All blends tested also contained 0.5% phenothiazine 9 and 0.0005% D.C.F. ZOO-60,000. The results are shown in Table 111.

Table III Percent Ryder Free Dibasic Acid in Blend Free Gear,

Acid Pounds Sebaeic Acid 0.01 3, 100 t1-Camphoric Acid- 0.012 3, 100 D0 0.015 3,100 Do 0.025 4, 400

We claim:

1. A lubricant composition consisting essentially of an ester-based synthetic oil of lubricating viscosity, about 0.001 to 5.0% by Weight of a base oil-compatible product formed by the reaction of a titanium tetraester with a glycol containing from 2 to about 24 carbon atoms, said titanium tetraester and glycol reacting in the ratio of about 0.5 to 4 moles of glycol to each mole of the titanium tetraester to enhance the load-carrying capacity of the esterbascd oil and an amount of camphoric acid sufiicient to provide increased load-carrying capacity to the composi- 1% tion, said ester-based oil being of an alkanol of 4 to 12 carbon atoms and an alkane carboxylic acid of 4 to 12 carbon atoms.

2. The lubricant composition of claim 1 in which the base oil is di-(Z-ethylhexyl) sebacate.

3. The lubricant composition of claim 1 in which the glycol titanate is about 0.1 to 2 Weight percent of the composition.

4. The lubricant composition of claim 3 in which the camphoric acid is about 0.01 to 0.1 weight percent of the composition.

5. The lubricant composition of claim 4 in which the camphoric acid is d-camphoric acid.

The Condensed Chemical Dictionary, 5th edition, 1956, Reinhold Publishing Company.

Claims (1)

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF AN ESTER-BASED SYNTHETIC OIL OF LUBRICATING VISCOSITY, ABOUT 0.001 TO 5.0% BY WEIGHT OF A BASE OIL-COMPATIBLE PRODUCT FORMED BY THE REACTION OF A TITANIUM TETRAESTER WITH A GLYCOL CONTAINING FROM 2 TO ABOUT 24 CARBON ATOMS, SAID TITANIUM TETRAESTER AND GLYCOL REACTING IN THE RATIO OF ABOUT 0.5 TO 4 MOLES OF GLYCOL TO EACH MOLE OF HE TITANIUM TETRAESTER TO ENHANCE THE LOAD-CARRYING CAPACITY OF THE ESTERBASED OIL AND AN AMOUNT OF CAMPHORIC ACID SUFFICIENT TO PROVIDE INCREASED LOAD-CARRYING CAPACITY TO THE COMPOSITION, SAID ESTER-BASED OIL BEING OF AN ALKANOL OF 4 TO 12 CARBON ATOMS AND AN ALKANE CARBOXYLIC ACID OF 4 TO 12 CARBON ATOMS.