US3383315A

US3383315A - Polyalkylene glycol-diorthosilicic acid ester lubricants and power transmitting fluids

Info

Publication number: US3383315A
Application number: US484120A
Authority: US
Inventors: Gothel Herbert; Noeske Heinz; Feichtinger Hans
Original assignee: Ruhrchemie AG
Current assignee: Ruhrchemie AG
Priority date: 1964-09-11
Filing date: 1965-08-31
Publication date: 1968-05-14
Anticipated expiration: 1985-05-14
Also published as: GB1045944A; NL6511639A; DE1262486B

Description

United States Patent R Claims. (Cl. 252--49.6)

The present invention relates to novel diorthosilicic acid esters for use as additives to synthetic lubricants. Lubricants for turbine engines must meet certain standard sepcifications, which also serve as guide-lines for the development of synthetic lubricants.

For example, the British specification Directionale of Engine Research and Development Material, Specif. vol., May 16, 1960, abbreviated D-Eng. RD, 2487, specifies a minimum viscosity of 7.5 cst. at 98.9 C. for some lubricants. The synthetic ester oils heretofore employed in this respect are mixtures consisting of lubricating oil stocks and viscosity increasing additives. Dibasic esters of aliphatic alcohols and dicarboxylic acids possessing viscosities in the range of 3 to 4 cst. at 98.9 C. serve as lubricating oil stocks. Added thereto are complex ester additives or thickening agents with a viscosity of 10 est. at 98.9 C. in adequate amounts in order to obtain mixtures with the required viscosity of 7.5 cst. at 98.9 C. (see Gunderson, Hart, Synthetic Lubricants, Reichold P. Corp, New York, 1962, p. 197). These complex ester additives are prepared by reacting aliphatic alcohols and diols with dicarboxylic acids; their molecular weights range around 800. Other thickening agents are polyoxyalkylenes and polyglycols respectively.

The aging resistance and the high temperaturecharacteristics of the above-mentioned additives are not completely satisfactory, especially under conditions prevailing in supersonic aircraft engines, in which high temperatures may occur in the bearings.

Heretofore, thickening agents could not be found, which were substantially satisfactory for these requirements. Thickening agents for mineral lubricating oils known in the art, as for instance polymethacrylates, improve the viscosity index of the basic oils, however, exhibit shearing stability that is too low, while highly viscous mineral oil products possess unsatisfactory low temperature characteristics.

It is therefore an object of this invention to overcome these and other difiiculties encountered in the art and to provide thickening agents for lubricants, which meet the requirements of supersonic aircraft turbine engines. The thickening agents are not only required to exhibit an excellent viscosity-temperature relationship and favorable properties at extremely low temperatures, but must also be resistant to aging and possess adequate lubricity.

It has now been found that these objects may be accomplished by the novel polyoxyalkyleneglycol-diorthosilicic acid esters of the invention which have the following formula:

Atosoa m aa mn wherein R represents a polyoxyalkylene radical having 3,383,315 Patented May 14, 1968 l to 6, and preferably 2 to 4 ether oxygen atoms, each alkylene group comprising 2 to 4, preferably 2 or 3 carbon atoms, R represents a radical of a monoester (semiester) of a saturated straight-/ or branched-chained carbox ylic acid having 6 to 20 carbon atoms with an alkylene-/ or oxyalkylene diol having 2 to 20 carbon atoms, R represents an alkyl group having more than 3 carbon atoms, preferably up to 20 carbon atoms, and/or a polyoxyalkyleneglycol ether radical having 1 to 6 ether oxygen atoms, n has a value from 0 to 4, and wherein the substituents R and R present in the molecule may be the same or different. In accordance with the invention, diorthosilicic acid esters of the formula:

3 3 ROgiOAOESSiOR and A(OSi)2(OR)s(OR) wherein A, R and R are as defined above constitute preferred diorthosilicic acid esters.

Depending on their viscosity, the esters of the invention are generally applied as thickening agents in amounts ranging from 5 to 7 0 volume percent and preferably from 25 to volume percent, in regard to the quantity of the entire admixture. They can be admixed with other fluid bodies known in the art as lubricants, as for instance with mineral lubricating oils, dicarboxylic acid esters, phosphoric acid esters, organosilicium compounds of different structure; they are especially well suited as thickening agents for ester oils of the lubricating range. They do not only increase the viscosity of the basic oil stock, but also improve the viscosity index. Oxidation inhibitors known in the art, for instance phenothiazine and conventional effective substances may be added to the mixtures comprising the esters according to the invention.

The diorthosilicic acid esters of this invention were hitherto not yet described. They may be prepared by the conventional methods employed for the production of diorthosilicic acid esters as known in the art. The novel esters can be prepared, for instance, by reacting stoichiometric amounts of suitable starting materials with gaseous SiCl, according to the disclosure of German Patent 1,142,855, or as disclosed in German patent application R 32,696, Auslegeschrift 1,180,359.

Especially suitable starting materials for the R-substitue-nts are, for instance, carboxylic acid semiesters of ethyleneglycol, diethyleneglycol, triethyleneglycol, tetraethylene-glycol, propyleneglycol, polypropyleneglycol, l, 6-hexanediol and the like. The acid components of the said carboxylic acid semiesters may be prepared by the so-called oxo-synthesis, as for instance, trimethylhexanoic acid and other acids, which can be obtained by hydroformylation (oxo-synthesis) of medium and higher ole fins, especially polyolefins, followed by air oxidation.

The properties of some mixed diorthosilicic acid esters, which can be applied according to the invention are set out in Table I which follows.

The esters of the invention listed in Table I are:

I. lDiethyleneglycol-di-orthosilicic acid hexaddiethyleneglycol-3,5,5-trimethylhexanoic acid ester)-este'r,

II. Triethyleneglycol-di-orthosilicic acid hexa (triethyL ene-glycol-3,5,5-trimethylhexanoic acid ester)-ester,

III. Triethyleneglycol di-orthosilicic acid-tri-(triethyleneglycol-3,5,5-trimethylhexanoic acid ester) tri (isodecyl)-ester,

IV. Triethyleneglycol-di orthosilicic acid-tri '(triethylene- @252 mi 5 a 3 o: S A a m aeo io mo mov 250550 emovmofioooxo moiov mofioo moiooio mo 2E2: ca Q2 5w N8 H a a m 10 65059 250550 36505000205059 mo moo mo moo mo mo 8:2: Q a: *3 can as A an H 3 go io moaov fimovo mo 5050500065059 moioo mo moo mo mo 2:52 EH m 2 N2 N5 0 m m m 5 0 0 emovo wo 35505000"65059 mofioo mofioc mo mo @252 3 a w m@ w; 8o H me H m 0 0 259050 qmovmoioooxo mofiov mo mooio moo mo mo $102 Me a; H 2 0 mm @8 a an H m 516 0 259050 emovmo mooozo mo mov mo moo mo moo mo mo 2:52 wo 02 N 2 5 so a m C movo mo emovmoioooxo moiov mo moofio moo mo mo 9:3: ow m2 5: FE $3 28 a o xfiovo moemovmofiooozciofiov mo moo mo mo n E 0 33a 0 Owen m m 4 22 .O 0 x35 ii E99;

5%? 53 m E s 5 62 H mama. F 5 w m m 4 glycol 3,5,5 trimethylhexanoic acid ester)-tri-(isotridecyl)-ester,

V. Triethyleneglycol-di-orthosilicic acid-tri (triethyleneglycol 3,5,5-trimethylhexanoic acid ester)-tri- (isooctadecyl)-ester,

VI. Triethyleneglyco1-di-orthosilicic acid-tri (triethyleneglycol-3,5,5 trimethylhexanoic acid ester)-tri-(diethyl- 1O ene-glycol-n-butylether)-ester,

VII. Triethyleneglycol-di-orthosilicic acid-tri-(triethyleneglycol-3,5,5-trimethylhexanoic acid ester)-tri-"(diethylene-glycol-ethyl-ether) -ester,

VIII. Triethyleneglycol-di-orthosilicic acid tri- (diethylene-glyco1-3,5,S-trirnethylhexanoic acid ester) tri-(diethylene-glycol-n-butylether)-ester.

These esters are prepared in the so-called bubble column reactor, according to the process disclosed in German patent application R 32,696, Auslegeschrift 1,180,- 359.

The properties of the esters according to the invention are in comparison with those of esters known in the art having equal R-substituents, but possessing no semi-ester substituents R, listed in the following Table II.

The known esters set out in Table II are:

11111. Triethyleneglycol-di orthosilicic acid hexa (isodecyl)-ester,

IVb. Triethyleneglycol-di-orthosilicic acid hexa-(isotridecyl)-'ester,

Vb. Triethyleneglycol-di-orthosilicic acid-hexa (isooctadecyl)-ester,

as well as the following esters, Which were heretofore proposed as lubricants:

VIb. Triethyleneglycol-di-orthosilicic acid-hexa-Kdiethyleneglycol-n-butylether)ester,

VIIb. Triethyleneglycol-diorth-osilicic acid tri diethylene-glycol-n-butylether) tri (diethyleneglycol-ethylether)-ester.

As is seen from a comparison of Tables I and II, the viscosity-temperature responsivity as well as the load carrying capacity of the esters according to the invention is influenced by the carboxylic acid ester radicals. Due to the substitution of these semi-ester radicals R in the molecule of the diorthosilicic acid esters their viscosity is considerably increased, except of ester V whose viscosity is somewhat lower than that of ester Vb, however, the viscosity index of ester V amounts to 127, while that of ester Vb is only 87.

If the ester molecule besides the carboxylic acid ester radicals additionally contains oxyalkylencglycolether substituents, an increase of the viscosity and an improvement of the viscosity-temperature relationship results.

The load carrying capacity of the lubricating films of the several esters hereinbefore described was determined by means of the four-ball apparatus, as described by Boerlage (Lexikon der Schmiertechnik, G. Voegtle, Franckhsche Verlags-handlung Stuttgart, 1964). In Tables I and II, in the column welding value, two values are given; the first number represents the highest load in kg. which the lubricating film being tested withstands for one minute without alteration, while the second number represents that load at which the balls are welded, i.e., frozen, together. The esters of the invention exhibit a better load carrying capacity than pure mineral oils and ester oils known in the art. The welding values of mineral oils amount to about /170 kg, those of dibasicester oils to 140/ kg. The esters of the invention I to VIII possessin comparison with esters III!) to Vb-a more favorable load carrying capacity of the lubricating films formed thereof. 75

TABLE II Molecd4 viscosity (est.) 2112- Viscosity Setting Welding Diorthosilicic ular index point, C. value load acid ester weight 378 C. 98.9 C. in kg Ib 1,140 0. 923 34.0 7.8 103 -68 160/170 1,398 0.905 56 9.2 138 -52 160/170 1,818 0. 897 740 35.9 87 +7.5 150/160 1,170 1.407 201 7.0 180 -70 180 190 1,086 1. 007 24, 25 6.80 185 69 180 190 Due to the influence of their substituents, derived from TABLE IV-CORROSION-OXIDATION TEST high boiling substances, the esters according to the in- Testing ndition of vention are substantially resistant to hydrolysis. They ex- D, Eng. R. D, 2487 Table III hibit outstanding low temperature characteristics, whlch 140 C 1 C would aid starting turbine engines at low temperatures 01" 22 h. :5 min. 32 h. temperatures encountered when flying at higher altitudes. 20 Without passing through of Without passing through of The setting points set out in Table I depend on the high air. air, 5 l./h. viscosity of the esters, which ranges above 180,000 Change of the viscosity at Change of the viscosity at and are not caused by solid deposlts. The sihcic acid es- 37.8 C. 37.8 C. ters of the invention remain flowable under pressure. Max. :5% See Table IH.

Their boiling points rang-e above 440" C. at 760 mm. Hg and above 180 C. at 0.015 torr respectively. This high boiling range assures a low volatility. Due to the advantages mentioned hereinbefore, the esters of the invention are especially well suited as lubricants for turbo-jet engines.

Laboratory and test stand examination have indicated the oxidative and thermal stability of the compounds of the invention. The change of the viscosity and the acid content forms a criterion for oxidative and thermal stability. Since corrosion of the bearing metals may occur on increasing acid content of the lubricant, the corrosive influence of the lubricating components is determined by way of the changes in weight of metal test stripes simultaneously with the resistance against oxidation occurring at high temperatures, which is also catalyzed by metals, as for instance copper.

In Table III, which follows, the increase of the neutralization numbers (nN), the percentage change of the viscosity, the deposit of slurry, the changes in weight of copper-sheet stripes due to oxidation at high temperatures as well as the amount of split oiI-liquid products as volatility-test are listed for the esters I to VIII according to the invention.

The values of Table III were determined under aggravated testing conditions, exceeding those of corrosionoxidation test standardized by specification D. Eng. RD. 2487 of May 16, 1960, but using the same methods described therein. The latter are set in comparison with the testing conditions applied to the esters of the invention in Table IV, which follows.

Increase of nN maximally up Increase of nN up to mg. to 0.5 mg. KOH/ g. KOH/ g. (see Table 111). Change in weight of copper Change in weight of copper stripes. sheet stripes (258 :2 mg. /cm. cm. =40 sq. inch).

See Table III.

The substances to be tested were at first subjected to the conditions mentioned hereinbefore for 16 hours in absence of copper and thereafter for 16 hours in presence of the copper sheet strip. (The values set out in the tables were determined after 32 hours.)

One percent by weight phenothiazine (dispersible, Cassella Farbwerke Mainkur) was added as an oxidation inhibitor to 300 ml. of each of the substances to be tested.

The data obtained from the esters of the invention were compared with those of dibasic esters known in the art. The average values of bis-2-ethylhexylsebacic acid ester are listed under N0. IX, those of some complex esters under No. X in Table III (identified in Gunderson, Hart, Synthetic Lubricants, Reinhold P. Corp, New York, 1962, p. 197).

The comparison of the diorthosilicic acid esters according to the invention with the esters known in the art indicates that the esters of the invention exhibit higher oxidative stability. Their corrosivity determined at 200 C. on copper ranges below the limiting value of 10.2 'n1g./cm. for the corrosion oxidation test at C. according to D. Eng. RD. 2487. Of considerable importance are the low slurry deposits or the slurry-carrying capacity of the diorthosilicic acid esters of the invention.

TABLE III.OXIDA'IIVE-STABILITY AND CO RROSIVITY TESTS Volatility test: amount Diorthosilicic acid Increasing of the Change of the Deposit of Change of of liquid products ester neutralization viscosity at slurry weight of split-01f in percent by number on mg. 37.8 C. in in percent copper, mg./ vol. of the charge KOH/g. percent 0111.

Above 1,0.

Since high altitude flight requires engine oils exhibiting low volatility, due to the low pressures encountered under such conditions, the evaporation of the esters was tested under aggravated conditions (passing air through at 200 C.) simultaneously with their oxidative stability. The amount of the liquid products split-off from the esters of the invention is generally lower than that or equal to that respectively split-01f from the known esters compared therewith.

The following examples are intended to illustrate the invention as certain embodiments thereof, and are not to be interpreted as limiting the same.

EXAMPLE 1 A reaction vessel (a socalled bubble-column reactor) consisting of a vertical glass tube with an internal diameter of 69 mm. and a height of 550 mm. provided with a glass frit (Jena apparatus glass, grain coarseness 2) in its bottom, was charged with 107 g. triethyleneglycol, 347 g. diethyleneglycol-n-butylether and 622 g. triethyleneglycol-monoisononanate, which had previously been dried to a water content below 0.1 percent. Silicon tetrachloride was applied dropwise from a dosing vessel into an evaporator coil heated at 80 C., which was gastight connected with the said reaction vessel, by a conduit joining the said reaction vessel below the said glass frit. The silicon tetrachloride vapors evolved in the evaporator coil were sucked through the frit under a vacuum of 180 torr. The ascending SiCl vapors together with the hydrogen chloride evolved during the reaction formed a bubblecolumn of 420 mm. height with the liquid in the reactor. The liquid reaction mixture, which had been preheated to was heated up to 52 C. by the heat of reaction. In order to compensate for the decreasing evolution of heat during the reaction, the reaction mixture was heated at about C. during the course of the reaction. 221 g. SiCL, were introduced and converted during minutes. After termination of the reaction, the reaction vessel was heated at C. for two hours, whereby dissolved hydrorator coil, which was gastight connected with the said reaction vessel by a conduit joining it below the said glass frit. The SiCl vapors were sucked through the glass frit under a vacuum of 180 torr into the reaction vessel. The liquid mixture, preheated to 40 C. was heated at 56 C. by the reaction heat evolved in the bubble column formed in the reaction vessel by the ascending vapors of silicon tetrachloride and hydrogenchloride evolved during the reaction together with the liquid reactants. The reaction was complete after 100 minutes. Hydrogen chloride dissolved in the reaction was removed at a vacuum of 18 torr under introduction of nitrogen from the reaction mixture heated to 110 C. (Thereafter, the Beilstein-reaction was negative.) The non-reacted excess liquid components (112 g.) were distilled off at 0.01 torr under heating up to 193 C. As distillation residue 848 g. diethyleneglycol-diorthosilicic acid-tri-(diethylene"lycoln-butylether)- tri-(dicthyleneglycolisononanate)-ester with the following properties were obtained: Density d =1.076; refraction adex zz =1.4530; viscosity at 989 C. 23.8 cst.; viscosity at 378 C. cst.; viscosity index: 144; viscositytemperature constant=0.824; setting point ranging at 50 C.; flame point 238 C.; silicon content 4.14 percent (calculated 4.07 percent).

In analogous manner other esters according to the invention may be prepared.

EXAMPLE III 80 parts by volume of diethyleneglycol-di-isononanate were admixed with 20 parts by volume triethyleneglycoldiorthosilicic acid tri-(diethyleneglycol-n-butylether)-tri- (ethyleneglycol-monoisononate)-ester (ester VI of the invention). The properties of the lubricant so obtained (hereinafter called admixture 80/20 percent by volume) are shown in comparison with those of its starting components in Table V, which follows.

EXAMPLE IV 50 parts by volume of diethyleneglycol-di-isononanate gen chloride was removed from the reaction mixture un- 40 were admixed with 50 parts by volume triethyleneglycolder introduction of nitrogen at a vacuum of 20 torr. diorthosilicic acid tri-(diethyleneglycol-n-butylether)-tri- (After the said treatment the Beilstein-reaction was nega- (diethylene lycol-monoisononanate)-ester (ester VIII of tive.) Thereafter, the non-reacted excess amounts of the the invention). The properties of the lubricant so obtained reactants (145 g.) were distilled off from the reaction (hereinafter called admixture 50/50 percent by volume) product under a vacuum of 0.01 torr up to a temperature 45 are also shown in comparison with those of its starting of 228 C. A distillation residue triethyleneglycol-diorthocomponents in the following Table V.

TABLE V n Viscosity in est. at Viscosity Setting Flame Welding 14- index point, point, value 10nd 93.9 C. 37.8 C. -40 C. 0. 0. in l'g.

l icthylcneglycol-diisononanatc 0. 43 3.12 11.8 3. 800 147 -65 215 ISO/1H0 Ester VI 1.069 124 590 260 400 m2 .3 251 150 190 Example III admixture 80/20% by vol 0. 983 7. 6 34. 73 11. 900 153 -65 228 10 /170 Ester vnr 1.072 20.5 110 42. $01) 151 -43 243 170 1130 Example 1V admixture fill/50 by vol 1.007 S. 02 40. 4 12, 110 15'! (St 230 /170 silicic acid tri-(diethyleneglycol-n-butylether)-tri-(triethyleneglycolisononanate)-ester (VI) having a density (1 :1069 and a refraction index 11 =1.458 was obtained. The silicon content of the product ester was determined to 3.72 percent (calculated 3.61 percent); the viscosity of the ester at 98.9 C. was 124 cst., at 378 C. 590 cst.; its viscosity index amounted to 162, its viscosity-temperature constant was 0.790, its flame point ranged at 254 C.

EXAMPLE II A so-called bubble-column reaction vessel consisting of a vertical glass tube having an interior diameter of 63 mm. and a height of 480 mm. provided with a glass frit (Jena apparatus glass, coarseness 2) in its bottom, was charged with a mixture consisting of 66.5 g. diethyleneglycol, 300.5 g. diethyleneglycol-n-butylether and 463 g. diethyleneglycol-monoisononanate, which had previously been carefully dried. From a dosing vessel, 194 g. silicon tetrachloride was applied dropwise into an evapo- Thus there has been described a novel composition and method for improving the viscosity, load bearing qualities, lubricity, corrosion resistance and volatility of composite lubricants by the addition of the diorthosilicic acid ester compounds of this invention to known lubricants. The novel compounds of this invention may also be used in applications such as power transmitting fluids, dampening fluids, electrical insulating fluids and the like, which are known in the art. Additions of the esters in this respect may also vary from 5 to 70 percent by volume, especially 25 to 70 percent by volume.

Although the invention has been described with reference to certain preferred embodiments, it is not intended that the invention is to be limited thereby, and any modifications of the novel compound, composition and method are intended to be included in the broad scope 75 of the invention as embodied in the following claims.

9 What is claimed is: 1. A lubricating oil comprising to 70 volume-percent of a diorthosilicic acid ester of the formula:

wherein A represents a polyoxalkylene radical having 1 to 6 ether oxygen atoms, each alkylene group comprising 2 to 4 carbon atoms, R represents a radical of a semi-ester of a saturated carboxylic acid selected from the group consisting of a straight-chained and branchedchained carboxylic acids having 6 to carbon atoms with at least one member selected from the group con sisting of alkylene and oxyalkylenediols having 2 to 30 carbon atoms, R is selected from at least one member of the group consisting of alkyl groups having more than 3 carbon atoms and polyoxyalkyleneglycol ether radicals having 1 to 6 ether oxygen atoms, and n is of the class consisting of 1 to 4 and 0, and R and R may be the same or different, and an ester lubricating oil.

2. A lubricating oil comprising a mixture of 5-70 volume percent of a diorthosilicic acid ester of the formula:

wherein A represents a polyoxyalkylene radical having 1 to 6 ether oxygen atoms, each alkylene group comprising 2 to 4 carbon atoms, R represents a radical of a semi-ester of a saturated carboxylic acid selected from the group consisting of straight-chained and branchedchained carboxylic acids having 6 to 20 carbon atoms With at least one member selected from the group consisting of alkylene and oxyalkylenediols having 2 to 30 carbon atoms, R is selected from at least one member of the group consisting of alkyl groups having more than 3 carbon atoms and polyoxyalkyleneglycol ether radicals having 1 to 6 other oxygen atoms, and n is of the class consisting of 1 to 4 and 0, and R and R may be the same or different, and 30 to 95% of a lubricating oil dilTerent from said diorthosilicic acid ester.

3. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-diorthosilicic acid-hexa-(triethyleneglycol-3,5,5-trimethy]hexanoic acid ester)-ester and an ester lubricating oil.

4. A lubricating oil comp-rising 5 to volume percent of triethyleneglycol-diorthosilicic acid-tri-(triethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(isodecyl)-ester and an ester lubricating oil.

5. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-diorthosilicic acid-tri-(triethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(di ethyleneglycol-n-butylether)-ether and an ester lubricating oil.

6. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-diorthosilicic acid-tri-(diethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(diethyleneglycol-n-butylether)-ester and an ester lubricating oil.

7. A lubricating oil comprising 5 to 70 volume percent of diethyleneglycol-diorthosilicic acid-hexa-(diethyleneglycol -3,5,5 trimethylhexanoic acid ester)-ester and an ester lubricating oil.

8. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-di-orthosilicic acid-tri-(triethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(isotridecyl)-ester and an ester lubricating oil.

9. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-di-orthosilicic acid-tri-(triethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(isooctadecyl)-ester and an ester lubricating oil.

10. A lubricating oil comprising 5 to 70 volume percent of triethyleneglycol-di-orthosilicic acid-tri-(triethyleneglycol 3,5,5 trimethylhexanoic acid ester)-tri-(diethyleneglycolethyl-ether)-ester and an ester lubricating oil.

References Cited UNITED STATES PATENTS 2,724,698 11/ 1955 Kittleson 25249.6 2,947,772 8/1960 Eynon 25249.6 X 3,029,269 4/1962 Abbott 25249.6 3,118,841 1/1964 Moreton 25249.6 3,133,111 5/1964 Wheeler 25249.6

DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,383 ,315 May 14 1968 Herbert G'othel et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 65, "R" should read A Column 2, line 4, "straight-/" should read straightline 5, "alkylene-/" should read alkylene- Column 4 TABLE I Second column,

line 6 thereof, "CH CH OCH CH OCH CH should read CH CH OCH CH OCH CH same TABLE I f r h column, lin 7 there of 2 2 2 2 2 2 J "(CH CH O) -C H should read (CH CH O) -C 2 S and 6, TABLE II, the first line comprising "acid ester" "weight", "37 8 C.", "98 9 C. and "in kg" should be canceled and inserted above the line separating the actual TABLE from the headings; same TABLE II, fourth column, line 6 thereof, "24, 25" should read 24.25 same columns 5 and 6, footnote tc TABLE III "Above 1 ,0 should read Ab ve 1. 0 Column 6, line 45, "Reinhold" should read Reichold Column 9 line 11, cancel "a".

H Columns Signed and sealed this 9th day of December 1969.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents

Claims

1. A LUBRICATING OIL COMPRISING 5 TO 70 VOLUME-PERCENT OF A DIORTHOSILICIC ACID ESTER OF THE FORMULA: