US3125531A

US3125531A - Certificate of correction

Info

Publication number: US3125531A
Authority: US
Publication date: 1964-03-17
Anticipated expiration: 1981-03-17

Description

United States Patent "ice 3,125,531 LUBRICATING COMPOSITION Howard J. Matson, Harvey, Ill., assignor, by mesne assignments, to Sinclair Research Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Jan. 3, 1961, Ser. No. 79,968 4 Claims. (Cl. 252--54.6)

The present invention relates to novel reaction products useful as synthetic lubricant additives. Addition of the reaction products of the present invention to synthetic lubricants provides the lubricants with improved extreme pressure properties.

The products of the present invention are polyesters prepared by direct esterification of an alkane dicarboxylic acid with a bis(chloro-4-hydroxy phenyl) alkane or by an ester interchange between the ester of the dicarboxylic acid and the bis(chloro-4-hydroxy phenyl) alkane. These reactions are continued for a time sufficient to produce a product that is compatible, i.e. soluble, miscible or dispersible with the synthetic fluid to which it is added. Ordinarily the polyesters are of lubricating viscosity, for instance having a kinematic viscosity at 210 F. of about 5 00 to 300,000 centistokes. The reaction products of the present invention are added to synthetic lubricants in amounts sufiicient to endow the lubricant with improved load carrying capacity, particularly as measured by the Falex extreme pressure test. Normally about 0.5 to 20 weight percent, preferably about 1 to weight percent of the polyester is employed.

The bis(chloro-4-hydroxy phenyl) alkane employed in preparing the additive of the present invention can be illustrated by the structural formula:

wherein R is a divalent aliphatic hydrocarbon radical of about 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, straight or branched chained, and n=1 to 4, preferably 1 to 2. The phenyl and R radicals may also be substituted with non-interferring groups. Suitable compounds are, for example, dimethyl, bis(dichloro-4-hydroxy phenyl) methane; dimethyl bis(tetrachloro-4-hydroxy phenyl) methane; bis(dichlbro-4-hydroxy phenyl) ethane; bis(tetrachloro-4-hydroxy phenyl) propane; diethyl, bis(dichloro-4-hydroxy phenyl) methane; diethyl, bis(tetrachlorol-hydroxy) methane, etc.

The alkane dicarboxylic acids employed in preparing the polyesters are dicarboxylic acids of the structural formula HOOCR-COOH wherein R is a divalent hydrocarbon radical generally containing 1 to 28 carbon atoms and includes the branched and straight structures which are saturated or unsaturated. The preferred acids are the saturated alkane dicarboxylic dibasic acids containing up to about 12 carbon atoms. Such acids include, for instance, succinic, adipic, suberic, azelaic, sebacic, brassic, brassylic, pentadecanedicarboxylic, etc.

When the reaction products are made by an ester interchange reaction, the esters of the above described dibasic acids are employed. The esters have the structural formula:

wherein R is as described above and R is a lower alkyl radical, i.e. of 1 to 5 carbons, preferably 1 to 3 carbon atoms. The esters used are those of the above acids and 3,l25,53l Patented Mar. 17, 1964 the lower aliphatic alcohols so that the alcohol produced in the reaction will be volatilized under the reaction conditions. Suitable esters include methyl sebacate, ethyl adipate, propyl azelate, isopropyl succinate, butyl sebacate, pentyl succinate, methyl brassylate and similar esters of the other dicarboxylic acids.

In preparing the reaction products of the present invention a molar ratio of 0.5 to 2.0 moles of the acid or its ester per mole of the chloro bisphenol compound preferably 0.8 to 1.25 is employed; the particularly preferred ratio being about 1:1. When the esterification reaction is conducted between a dibasic acid and the phenol it is continued with concomitant boiling-off of water from the reaction mixture until the product has the desired viscosity. The temperature of this reaction is usually at least about 300 F. and should not be so high as to decompose the wanted product. If desired, the reaction can be conducted in the presence of a solvent, for instance an aromatic hydrocarbon such as xylene, and to provide a better reaction rate I prefer to employ an acid esterification catalyst. Many of these catalysts are known and include for instance hydrochloric acid, sulfuric acid, aliphatic and aromatic sulfonic acids, phosphoric acid, perchloric acid, hydrobromic acid, hydrofluoric acid and dihydroxyfluoboric acid. Other catalysts are thionyl chloride, boron trifluoride, silicon tetrafluoride, the chlorides of magnesium, aluminum, iron, zinc, copper and tin and salts of mercury, silver, cobalt, nickel and cerium. In the preferred reaction, when employing the dibasic acid, I use about 0.1 to 05 weight percent of paratoluene sulfonic acid catalyst, a xylene solvent and a temperature of about 345 to 390 F. while boiling-off water by refluxing.

When employing the esterification or ester interchange alcoholysis reaction between the dicarboxylic acid ester and the phenol, I prefer not to use a solvent and the temperature is generally above 350 F., but not so high as to decompose the Wanted product. Advantageously, the temperature is in the range of about 435 to 480 F. Many ester exchange catalysts are known and include for instance, zinc stearate, aluminum stearate, dibutyl-tin oxide, titanium tetraesters of lower aliphatic alcohols, sodium acid sulfate, sulfuric, hydrochloric and sulfonic acids, aluminum alkoxides, sodium methyl carbonate. Also, these catalysts are exemplified by the alkali metal and alkaline earth metal alkoxides, hydroxides and carbonates.

In both the direct and ester interchange reactions the reaction is continued with concomitant boiling-off of water (direct esterification) or alcohol (ester interchange) from the reaction mixture until the polyester has a kinematic viscosity of at least about 500 centistokes at 210 F. The polymerization should not be continued for so long a period that a product insoluble in synthetic fluids results. The polyester additive ordinarily will have a viscosity of about 500 to 25,000 centistokes at 210 F., preferably about 750 to 1500 centistokes. When the heating is stopped a capping alcohol can be added to the reaction mixture to tie up any remaining acid. Suitable capping alcohols are, for example, low molecular Weight alkanols of up to about 20 carbon atoms, preferably the lower normal alkanols of 1 to 5 carbon atoms. Other materials such as alkylene oxides may be used instead of the alkanols.

The synthetic fluids to which the reaction products of the present invention are added are ester-based oils of lubricating viscosity and may be, for instance, a simple ester or compounds having multiple ester groupings such as complex esters, polyesters, or diesters. These esters are made from monoand polyhydroxy aliphatic alcohols and aliphatic carboxylic acids, frequently of about 4 to 12 carbon atoms, aliphatic including cycloaliphatic. The term alkanol is used to designate the monoand polyhydroxy alcohols 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 X--YZY-X 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 X represents a monoacid residue, Y represents a glycol residue and Z represents a dibasic acid residue are also considered to be complex esters. complex esters often have 30 to 50 carbon atoms. Polyestcrs, or polyester bright stocks, can be prepared by direct esterification 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 130 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, such as 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 as a methyl silicone polymer or other additivcs 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 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, iso-octyl and dodecyl alcohols, C oxo alcohols and octadecyl alcohols. C to C branched chain primary alcohols are frequently used to The improve the low temperature viscosity of the finished lubricant composition. Alcohols usch as n-decanol, 2- ethylhexanol, oxo alcohols, prepared by the reaction of carbon monoxide and hydrogen upon the olefins obtainable from petroleum products such as diisobutylene and C olefins, ether alcohols such as butyl carbitol, tripropylene glycol monoisopropyl ether, dipropylene glycol monoisopropyl ether, and products such as Tergitol 3A3, which has the formula C H O(CH CI-I O) H, are suitable alcohols for use to produce the desired lubricant. If the alcohol has no hydrogens on the beta carbon atoms, it is neo-structured; and esters of such alcohols are often preferred. In particular, the neo-C alcohol2,2,4-trimethyl pentanol-l-gives lubricating diesters or complex esters suitable for blending with diesters to produce lubricants which meet stringent viscosity requirements. isooctanol and isodecanol are alcohol mixtures made by the 0x0 process from C -C copolymer heptenes. The cut which makes up isooctanol usually contains about 17% 3,4-dimethylhexanol; 29% 3,5-dimethylhexanol; 25% 4,5-dimethylhexanol; 1.4% 5,5-dimethylhexanol; 16% of a mixture of 3-methylheptanol and 5-ethylheptanol; 2.3% 4-ethylhexanol; 4.3% a-alltyl alkanols and 5% other materials.

Generally, the glycols contain from about 4 to 12 carbon atoms; however, if desired they could contain a greater number. Among the specific glycols which can be employed are 2-ethyl-1,3,hexanediol, 2-propyl-3,3-heptanediol, Z-methyl-1,3-pentanediol, 2-butyl-1,3-butanedio1, 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 alltylene radical contains 2 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 -300 and Z-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 con ducted 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, u,u'-diethyl adipic acid and sebacic acid. This composite of 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 Olf 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; 2,703,724 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-(2-ethylhexyl) sebacate, ethylene glycol dilaurate, di-(Z-ethylhexyl) phthalate, di-(1,3-methylbutyl) ad-ipate, di-(Z-ethylbutyl) adipate, di-( l-ethylpropyl) adipate, diethyl oxylate, glycerol trim-octoate, di-cyclohexyl adipate, di-(undecyl) sebacate, tetraethylene glycoldi-(Z-ethylene hexoate), di-cellosolve phthalate, butyl phthallyl butyl glycolate, di-n-hexyl rfumarate polymer, dibenzyl sebacate, and diethylene glycol bis (Z-n-butoxy ethyl carbonate). Z-ethylhexyl-adipate-neopentyl glycyladipate-Z-ethylhexyl, is a representative complex ester. Generally, these synthetic ester lubricants have a viscosity ranging from light to heavy oils, e.g. about 50 SUS at 100 F. to 250 SUS at 210 F., and preferably 30 to 150 SUS at 210 F.

The esters are manufactured, in general, by mere reaction of the alcoholic and acidic constituents, although simple esters may be converted to longer chain components 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 influences 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 80 NaHSOr, aliphatic and aromatic sulfonic acids, phosphoric acid, hydrobrornic acid, HF and dihydroxyfluoboric acid. Other catalysts are thionyl chloride, boron trifiuoride and silicon tetrafluoride. Titanium esters also make valuable esterification and transesterification catalysts.

In a preferred react-ion, 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 165 to 200 C. while refluxing water. The temperatures of the reaction must be sufiicient 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 C., preferably not over about 175 C. The pressure is conveniently about atmospheric. Although reduced pressure or superatmosphenic pressure could be utilized, there is usually no necessity to use reduced pressures, as the temperatures required at atmospheric pressure to remove the water formed do not usually unduly degrade the product.

If desired other additives may be added to the synthetic lubricant compositions of the present invention to improve other characteristics of the lubricant so long as they do not deleteriously affect the functional properties of the composition. Such additives are, for instance, antioxidants, viscosity index improvers, corrosion inhibitors, other extreme pressure agents, etc.

The following examples are included to further illustrate the reaction products of the present invention and the properties of lubricants containing them but are not to be considered limiting.

EXAMPLE I 50 grams of tetrachlorobisphenol (0.13 mol.) and 31 grams of sebacic acid (0.13 mol. plus 20% excess), 0.5 gram of toluene sulfonic acid, and 250 ml. of toluene d were placed in a 1 liter 3-neck flask equipped with thermowell, water trap and condenser, and stirrer. After about 8 hours of reflux at C. pot temperature, a few drops of cone. H 504 were added. Reflux was continued for 23 hours, collecting :a total of 3.8 ml. water of reaction, or about 81% of theory. 40 grams of Z-ethylhexyl alcohol were then added, and refluxed for 6 hours to esterify any unreacted sebacic acid. Solvent and excess alcohol were removed by vacuum stripping at 150 C. The recovered product was designated product A and analyzed 17.8% chlorine (theoretical 19% based on dilution).

EXAMPLE II 222 grams of 2,5-dichlorobisphenol (0.75 mol.), 151 grams sebacic acid (0.75 mol.), 1 gram of NaHSO and 500 ml. of toluene were combined in a 2 liter, 3-neck flask equipped with stirrer, water trap and condenser, and thermowell. After about 6 hours reflux at 150 C., since no water or reaction was evolved, 1.5 grams of p-toluenesulfonic acid was added to the reaction mixture. After about 45 hours of reflux, 17 m1. of water or about 63% of theory were collected. 100 grams of 2-ethylhexanol were then added and refluxed for 16 hours, collecting an additional 10 ml. of water, equal to theory. The solvent and excess alcohol were removed by stripping under vacuum to C. The recovered product was designated product B and analyzed 12.2% chlorine (theoretical 12.6% based on dilution).

Oil blends of Plexol 201-1 (di-Z-ethylhexyl sebacate having 0.02% free sebacic acid) and various concentrations of the polyesters of Examples I and II were prepared and tested for load-carrying ability in the Falex lubricant testing apparatus and the SAE extreme pressure testing machine. Plexol 201-] without the additive was also tested. The results are shown in Table I below.

For comparative purposes various concentrations of the diester and polyesters prepared in accordance with Examples III to VI below in Plexol 201-] were also tested.

EXAMPLE III Dibutyl chlorendate was prepared by refluxing 371 grams (1 mol.) of chlorendic anhydride, 300 grams of n-butyl alcohol (4 mols.) and 2.5 grams of p-toluenesulfonic acid, until the theoretical amount of water (18 ml.) had been collected in a water trap. The excess water was then removed under vacuum to a pot temperature of C. The product was designated product D and analyzed 42% chlorine (theoretical 42.5%).

EXAMPLE IV EXAMPLE V This product was prepared by reacting chlorendic anhydride with polyethylene glycol chloride in accordance with the method of Example IV. It was topped to 150 C./ 15 mm. The product analyzed 37.2% chlorine (theoretical 38.7) and was designated Product I.

EXAMPLE VI This product was prepared by reacting sebacic acid with polyethylene glycol chloride (having an average molecular weight of 210) in accordance with the method of Example IV. It was topped to 150 C./10 mm. and analyzed 10.9% chlorine (12.1% theoretical). It was designated Product I.

The results of the tests on oil blends containing the products of Examples 111 to V1 are also shown in Table I below for purposes of comparison:

c; l to 8 carbon atoms and :2 equals 1 to 4, the molar ratio of said selected acid and ester to said chlorobisphenol reacted being 0.5 to 2:1.

Table I Viscosity, cst., at Falcx (lbs.) SAE 210 F. Conc Sate Additive Reactants Class per- Load cent (lbs.) Actual Extrap b Pass Fail None r 1,250 1,500 108 A tetrachloro-bis phcnol+scbaeic acid (17.8% C1). Polycster 722 12,000 i 2 0. 5 1500 1, 750 336 B dichlorobisphcnol sebacic acid (12.2% C) 40 1, 000 2.0 4, 500+ None 358 5. 0 4, 500+ None 410 0. 5 500 1, 750 328 D butyl alcohol ehlorendic acid (42% C1) Dicster 8 8 1, 500 1, 750 386 436 H lauryl alcohol ehlorendic acid (27.8% o1 d0 11 11 I P 379535? (glycol chloride chlorcndic do 28 a g aci J Polyeggygn glycol chloride sebaeic acid s. do 9 9 10. O l). 1 y

* Plcxol 201-1 which is di-2-ethylhexyl sebacate sebacie acid (free).

b Actual viseosity-with esters A-B and I there was unreacted acid and viscosity was on this product and extrapolated for ester viscosity.

The data of Table I demonstrates the improved load carrying capacity of synthetic lubricants containing the polyesters of the present invention (A or B) when compared to the load carrying capacity of the synthetic oil alone. With respect to the diesters tested, the results show that while the SAE load value of lubricants containing those additives may be comparable to the SAE load values provided by the additives of the present invention, the Falex test values are far inferior. The difierence is even more significant when considering the fact that 3 of the 4 comparative ester products tested contained a much higher percentage of chlorine.

I claim:

1. A lubricant composition consisting essentially of an ester-based synthetic fluid of lubricating viscosity, said ester-based fluid being of an alkanol of 4 to 12 carbon atoms and an alkane carboxylic acid of 4 to 12 carbon atoms and a minor amount suificient to improve loadcarrying capacity of said fluid of a base oil-compatible polyester reaction product of a material selected from the group consisting of a dicarboxylic acid having the structural formula:

and an ester having the structural formula:

ROOCRCOOR' wherein R in said formulae is an aliphatic saturated divalent hydrocarbon radical of 1 to 28 carbon atoms and R is a lower alkyl radical of 1 to 5 carbon atoms, and a chlorobisphenol having the structural formula:

wherein R is a divalent aliphatic hydrocarbon radical of 2. The composition of claim 1 wherein R in the structural formula of said ester and acid is a saturated divalent hydrocarbon of up to 12 carbon atoms.

3. The composition of claim 1 wherein the amount of the polyester reaction product is about 0.5 to 20 weight percent.

4. A lubricant composition consisting essentially of an ester-based synthetic fluid of lubricating viscosity, said ester-based fluid being of an alkanol of 4 to 12 carbon atoms and an alkane carboxylic acid of 4 to 12 carbon atoms and about 0.5 to 20 Weight percent of a base oilcompatible polyester reaction product of a dicarboxylic acid having the structural formula:

HOOC-R-COOH wherein R is an aliphatic divalent hydrocarbon radical of up to 12 carbon atoms and a chlorobisphenol having the structural formula:

wherein R is a saturated divalent aliphatic hydrocarbon radical of 1 to 6 carbon atoms and n equals 1 to 2, the

mole ratio of said acid to said chlorobisphenol reacted eing about 0.5 to 2.0: 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,058,394 Arvin Oct. 27, 1936 2,147,547 Reiff et al Feb. 14, 1939 2,255,085 Prutton et al Sept. 9, 1941 2,460,035 Rogers et al Jan. 25, 1949 2,569,122 Adelson Sept. 25, 1951 2,971,913 David et al Feb. 14, 1961 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,, 125,531 March 1? 1964 Howard J, Matson It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column I line 52 strike out 'saturatedM and insert the same before divalentM in line 6O same column "Ia Signed and s ealed this 10th day of November 1964,

(SEAL) Altest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF AN ESTER-BASED SYTEHTIC FLUID OF LUBRICATING VISCOSITY, SAID ESTER-BASED FLUID BEING OF AN ALKANOL OF 4 TO 12 CARBON ATOMS AND AN ALKANE CARBOXYLIC ACID L OF 4 TO 12 CARBON ATOMS AND A MINOR AMOUNT SUFFICIENT TO IMPROVE LOADCARRYING CAPACITY OF SAID FLUID OF A BASE OIL-COMPATIBLE POLYESTER REACTION PRODUCT OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF A DICARBOXYLIC ACID HAVING THE STRUCTURAL FORMULA: