DE2060750A1 - Synthetic ester lubricating oil - Google Patents

Description

SYNTISTIC ESTER OIL

The invention relates to a lubricating oil for use in gas turbine or jet engines. Turbine engines have to work under extreme environmental conditions and generate during the Operating time inside the engine Temperatures of 204 to 260 ° C and more. These operating conditions are, in turn, a burden the lubricating oil is very strong, so even the best mineral oil-based lubricating oil compositions are not for turbine engines can be used.

Synthetic ester lubricating oils are already used with good success for the lubrication of turbine engines carefully balanced mixture of additives. These ester oils stay within a large one Temperature range and also prove to be resistant to the effects of heat, wear, pressure and oxidation stable, while at the same time they have good lubricating properties.

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BATH ORIGINAL

With the introduction of modern and more powerful turbine engines, which are supposed to raise the level of supersonic air traffic, the lubricating oil is simultaneously exposed to higher ■ heat and oxidation loads.

US Pat. No. 3,427,111 describes a synthetic lubricating oil in which a pentaerythritol ester oil is used, which 1) antioxidants of the arylarain type such as diphenylamine and phenyl-ci-naphthylamine, 2) a corrosion inhibitor to protect the copper surface such as a salt of 1-Salicylalaminoguanidins and an aliphatic carboxylic acid having 14-13 carbon atoms, 3) a Iletallinaktivierungsmittel, particularly PoIyhydroxyanthrachinon (Diphenylenketon) and 4) an organic phosphorus-Ψ ester contains in the form of a phosphate or phosphite.

In U.S. Patent 3,414,610, antioxidants are used for Use in synthetic ester lubricating oils described which contain additives from the group of the alkylphenylnaphthylamines.

The invention relates to a synthetic ester lubricating oil, consisting essentially of a reaction product of pentaerythritol or trimethylolpropane with an organic honocarboxylic acid with 2-18 carbon atoms, characterized by proportions of

a) about 0.3-5% by weight of an alkyl- or aralkyl-phenylnaphthylamine, whose alkyl radical has 4-12 carbon atoms,

b) about 0.3-5 wt .-? o of a dialkyldiphenylamine, its Alkyl radicals have 4-12 carbon atoms,

c) about 0.001-1% by weight of a polyhydroxyanthraquinone and

d) about 0.25-10% by weight of a hydrocarbon phosphate, the hydrocarbon -ReBt of which has an aryl ring and 6-18 carbon atoms .

The lubricating oil of the present invention represents a significant advance in terms of soiling inhibition, corrosion resistance in the case of stainless steel, and excellent heat and oxidation resistance. These special properties were obtained

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one by carefully weighing and formulating a synthetic Lubricants based on kster. The results were 'surprising and unexpected in that they deal with a matched or exceeded excellent commercial synthetic ester lubricating oil and by means of a largely and carefully modified one Lubricating oil composition have been achieved, v; although this combination " Settlement does not contain such an additive as is used for the manufacture of the synthetic that is well-established on the market Lubricating oil is deemed essential.

The main component of the lubricating oil according to the invention consists from one made from pentaerythritol or trimethylblpropane and a mixture of hydrocarbon moriocarboxylic acid liquid ester. Polypentaerythrites such as di-, tri- and tetrapentaerythritol can also be used to produce the base oil will.

The hydrocarbons used to make the liquid ester -Monocarboxylic acids include straight and branched chain aliphatic ^ acids, cycloaliphatic acids, and aromatic Acids and their mixtures. The acids used have 2 to 10, preferably 5 to 10, carbon atoms per molecule. Suitable specific acids are, for example, vinegar, propionic, butter, valerian, isovalerian, capron, decane, hexadecane, Vinylbenzoic, dodecylbenzoic, pelargonic, cyclohexanoic, naphthenic, benzoic, phenyl acetic, tert-butyl acetic and 2-ethyl lexanoic acids.

In general, the acids are reacted in such a ratio that the end product is a fully esterified pentaerythritol or trimethylolpropane, in which the pentaerythritol tetraesters form the preferred ester bases. A commercially available tetraester is, for example, pentaerythritol tetracaproate, which is produced from purified pentaerythritol and an untreated caproic acid containing still other monobasic acids with 5-10 carbon atoms. Furthermore, a tetraester is also suitable which is composed of a technical pentaerythritol _fi and a 38% valerian, 13% 2-methylpentane, 32% octane.; -, un4 _:? 17 # v? Elargonic acid containing mixture is prepared. Other suitable ester bases are trimethylol

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propane triheptariat, trimethylol propane pentanate and trimethylol propane hexanate.

The ester represents the main part of the ready-to-use syn-

represent
thetic lubricating oil /. Generally, this liquid ester is present in the lubricating oil in 90-98% concentration.

The essential alkyl or alkarylphenylnaphthylamine component of the lubricating oil according to the invention is represented by the following formula:

I I

in which R is an alkyl or alkaryl radical with about 4-12 carbon atoms. This radical can be a straight-chain or branched-chain alkyl radical, preference being given to the tert-alkyl structure, or it can be an alkaryl radical. The naplithylamine can either be o (- or ß-naphthylamine. Specific useful compounds from this group are, for example, Npt-octylphenyl-oC-naphthylamine, N- (p-aL-cumylphenyl) -o-ÖC-cumyl-ß-naphthylamine, Npt -octylphenyl-ß-naphthylamine and the corresponding pt-dodecylphenyl, pt-butylphenyl and p-dodecylphenyl-ii- and -ß-naphthylamine.This component is preferably used in a concentration of about 0.5 to 2.5% .

Another important component of the lubricating oil according to the invention is dialkyldiphenylamine. Compounds of this type are represented by the formula

characterized in which R is an alkyl radical with about 4-12 carbon atoms. Suitable alkylamines include dioctylphenylamine, didecyldiphenylamine, didodecyldiphenylamine, dihexyldiphenylamine and other similar compounds. Is preferred

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Dioctyldiphenylamine, preferably in a concentration of 0.5 to 2.0 %,

AXa essential MetaXXinaktivierungsraitteX is used in the invention SehmieröX used a PoXyhydroxyanthraquinone. Suitable. Compounds from the group of the PoXyhydroxyanthraehinones are dihydroxyanthraquinone such as 1,4-dihydroxyanthraquinone, which is also known under the name of Chinizarin, 1,5-dihydroxyanthraquinone and 1,8-dihydroxyanthraquinone as well also the higher FoXyhydroxyanthraquinones. This component is preferably used in a concentration of about 0.01 to 0.5 wt.

AX's X last specific component of the lubricating oil according to the invention is a HydroearhyXphosphatester, more precisely a tri. hydrocarbyXphosphate, in which the HydrocarbyXrest is an AXkyX-, AryX-, AXkaryX-, ZykXoaXkyX «or AraXkyX- radical or © in a mixture of these with 2 to 12, preferably 4 to 8 C atoms, AXs gweetaBäßigss-specific compounds geXten TricresyXphosphat , CresyXdiphenyXphosphat, TriphenyXphosphat, TributylLphosphat, Tri (2-A'thyXhe3cyX) -phosphat and TrizykiohexyX-phasp. ^ At: * - These 'compounds are in the ScliraieröXzusamraensetzung, ypFzugweige in a concentration of about 0.5 to 5 %

The vision according to the invention was now according to the below 1.5 Brdco bearing test and the Erdco screening test described tested, of which the first information about its resistance to oxidation and corrosion and the last about the SoXXte.

The oxidation and corrosion tests, apart from the deviations specified under MXL- «L> 23699B, are carried out according to method no. 5308.4 of the FederaX Test Method and Standard No. • 791a (US-examination and NermvorSchriften) for 72 hours at 204 ° C or above 72 Stundtn at 318.3 ⁰ C. The bath temperature is gehaXten at each 204 and 218.3 ^Q C + 0.55 ⁰ C instead of 121.1 ⁰ C, and

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the tests last 72 instead of the originally required one. 168 hours.

In the Erdco screening test used to test lubricating oil an oil sample is taken under controlled conditions for a predetermined period of time in a ventilated and circulated a heated test chamber containing aluminum tubing. Upon completion of the test, three major sections of the aluminum tube are checked for contamination, and any debris or the formation of stains is recorded and given a numerical value, so that afterwards one has a total rating of

has a defect. .

In this experiment, is mainly engaged in the under no. 5003 ^(f of the U, S, -Normvorschriften described for testing procedures worked ■ "■> ■ Wright Air Development Center Deposition Test Rig (pilot plant for testing of pollution), said plant but as follows modified is:

1) Instead of the filter ("line" filter), an aluminum tube 83.9 cm long and 0.477 cm in diameter was used.

2) Instead of the filling bottle, a substitute container marked with graduation marks was used.

3) The oil cooler was only used to cool the oil after the end of the experiment.

4) The oil temperature controller was not used. P 5) The filter pressure meter has been switched off.

The sleeve-shaped heated end of the coking tube is mounted by means of a clamping device and rotates at a speed of 1700 to 1800 revolutions per minute. All dirt on the pipe is removed with paper of the type No. 400 silicon carbide , and then the pipe is wiped with a soft, clean cloth. The air stream is adjusted so that flow C at atmospheric pressure and a temperature of 48.9 + 2.8 ⁰ 300ml saturated air per minute; the heat controller is set to 273.9 ⁰ C.

After the apparatus has been rinsed with oil for ten minutes, the container is filled to the 100 ml graduation

10 9826 / 15-43

BATH ORIGINAL

, _r , " 2080750

topped up with fresh oil. Ira coking vessel -will be the oil st and.-held approximately 12.7 mm above the bottom of the glass.

The experiment is carried out as follows:

The Verkokungsrohr is fueled and set the controller to 149 ⁰ C. This temperature v, ^r is maintained for five minutes and then the controller is set to 204 ° C. After the same dwell time at this temperature, the controller dam is set to 316 ^° C. As the oil heats up and expands, so much must be drained of the latter that the oil level is kept between two and a half inches above the bottom of the glass coking vessel. Uniform heating conditions are maintained by the oven temperature and the above-mentioned correct level of the oil covering the coking pipe. New oil is fed in according to the evaporation in order to maintain the correct oil level. After a test duration of six hours, the coking heating is switched off, the water cooler is switched on and the oil is allowed to cool to a temperature of 121.1 ° C. All switches as well as the water and air supply are switched off.

*pipe

After about an eighteen hour break, the experiment is restarted and allowed to continue for an additional six hours under the normal experimental conditions, just as the first time. (You may have to refill it for 5 to 10 ml of new oil to the oil level again to bring mm above the bottom of the glass Verkokungsgefäßes to about 12.7.) After completion \ this second heating season will turn off the heating, allowed the oil to cool and stops the air supply. The feed oil is drained and the coking tube is removed from the coking hood. It is soaked in n-pentane until all visible traces of oil have disappeared; then the tube is then air-dried

The coking tube is assessed as it was removed from the coking vessel on the side facing the vent. To determine the defect marks is placed with a distance of 12.7 mm lines in the template provided on the main roles, wherein the ^ m values are 25.4 mm and 12.7 lines corresponding to the boundary surface between the steam and oil gt Angei.

109826 / 154.3 ORIGINAL BATHROOM

For each 12.7 mm segment, four are the type and thickness of the deposits graded with a numerical value on the inspected areas. Unless the deposits are within a segment vary, take the highest number. A sealed factor is determined for each of the three graded main areas, to take into account the relative importance of each area. The overall deposit score is obtained by the deposits of the main surfaces are summarized and multiplied by the weighted factor. The sum of three area defects, divided by 2 gives the total deposition grade.

The following table shows the standard grades for the coking tube:

Type of Easy middle Strong deposit 1 3 5 Coating or stain 9 10 11th Coal, smooth 12th 13th 14th "rippling 15th 16 17th "blistered 18th 19th 20th "scaly

It turned out that the test results could be reproduced well and also with the data obtained with the 1.5 Erdco-Bearing-Test with regard to coating and char formation agree well.

The base oil A contained in the following, tested lubricating oils was a technical pentaerythritol with a lower proportion of dipentaerythritol, which was mixed with a (in mol % about 38 % valerian, 13% 2-methylpentane, 32% n-octane and 17 % Pelargonic acid-containing fatty acid mixture was esterified, the average carbon chain length being about 6.5. This base oil had the following properties:

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ν ^: ■ -. , ■

Viscosity, cS-t at 98.9 ° C 4.93

cSt at 37..8 ⁰ C 25.6

¹¹ , cSt at -40 ⁰ C 7023

Viscosity index 131

Flash point, ⁰ C 254

Ryder Gear, kg / cm 364.63

The base oil B was a pentaerythritol of technical quality, which with a, (in M ₀ I-Jo) about ~ \ 2% Isovalerian-, 27/4 Valerian-, 8% Capron-, 1450 Heptyl-, 19 # Capryl- and 13 ^ pelargonic acid containing fatty acid was gcinically esterified.

The base oil C was a technical pentaerythritol, which with j one (in HoI-Jo) about Ο> ό isovaleric, 23 ^> valerian, 20% caproic, 27/4 heptyl, 7 % caprylic and 16% pelargonic acid containing fatty acid mixture was esterified.

The composition of the lubricating oils according to the invention and the comparison oils and the results of the oxidation and corrosion tests are contained in Table I below. The lubricating oils E, G, H and I are made according to the invention been.

The base oil D was a technical pentaerythritol, which with a (in mol%) about 18 # isovalerian, 39/6 valerian, 2/0 caprylic and 4θ? Ό fatty acid containing pelargonic acid

mixture was esterified.

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TABBLIS I
Synthetic lubricating oil Oil A Ol B ' oil

Basic fluid A 96.4 95.9 96.9

N-phenyl-naphthylamine

N- (p, t-octylphenyl) -OC-naphthylamine - 1> 50 1.50

ρ, ρ'-üi-t-octyldiphenylamine 1.00-1.00

Tricresyl phosphate 2.00 2.00

Quinizarine 0.10 0.10 0.10

OT αο N- (p-t-octylphenyl) -ß-naphthylamine - - - - ^

0 * £ o _c

g - Oxidation / corrosion (temp./time) 204/72 h 218.3 / 72 h 204/72 h 213.3 / 72 h 204/72 h 213.3 /? 2h

1 Ot corrosion, Cu (mg / cm ² ) -0.95 ~ -0.05 - -0.0c

2 ^ Fe 0 +0.02 0 +0.03 0 0 r- ^ Al 0 0 -0.04 0 -0.03 0

Mg -2.82 - -0.05 - -0.03

Ag 0 0.04 -0.05 0 -0.02

Ti - 0 - 0 - 0

Ti - 0 - +0.02 - 0

Increase d. kin. Visc., % (At 37.3 ° C) 77 110 15 91 20

Increase d. Total acid number 6.96 9.16 -1.98 7.22 0.63 9.77

Sludge (g / 100 ml) 0.00o5 0.0094 0.0039 0.0032 0.0092 0.0033

¹ 'These oils contained, inter alia, an addition of 50 ppm dimethyl silicone to prevent the formation of gaze and 0.50 wt .-; - 6 bis (2,2,4-trimethylphenxyl) ester of a commercially available linoleic acid dimer. _< ~ ^

Oil D ¹

95.0

01 E.

TABDLKS I (cont.)

94.9

Oil F ^

(commercial ugly oil)

Oil G

95.4

1.50 1.00 2.00

204/72 H

-0.46

O
-0.03

24.2
1.26 0.0036

1 , 50 0 204/72 h 218.3 / 72 h - 0 1 , 00 +0.04 -0, —— +0.03 2 , 00 __ 0 +0.06 +0.04 O , 10 0 0 0 52.0 204/72 H 0 0 5.03 O -0.02 0 0.024 O 40 - O 4.5 _. O 218.3 / 72 h D, 0096 2 ' O 0, __ 0, —— , 06 19th 1.67 0.0041 C. 1.0 , 98 , 009

1.50 1.00 2.00 0.10

2Q4 / 72h

-0.07 +0.02

0
+0.02

19.0 0.88 0.001

A commercially available oil with an additional component consisting of 0,10 ^ aliphatic carboxylic acid salt of 1-salicylalaminoguanidine with 14-18 carbon atoms.

Oil H

TABLE I (cont.)

Oil I ¹

95.4

94.9

1,
1,
2,
O, 50
OO
OO
10 , 04 204/72 h , 04 -O +0 O O O

1.00 2.00 0.10 1.50

204/72 h

+0.08 +0.06 +0.05 +0.04 +0.06

MIL-L-256993 regulation

204- / 72 h 218.3 / 72 h + 0.4 —— ± o » ² +0.2 ± 0.2 +0.2 + 0.2 - ± Ο » ² ± 0.2 —— +0.2

21.0 0.89 0.001

0.74

0.0034

- 5 to +25 -5 to +50 3 max. 6 max.

0.050 max. 0.050 max.

-.13 -

The military provided for the oxidation and corrosion tests Requirements are of the lubricating oils A, B, C and D before albin due to their very low viscosity and the lack of stability against acid formation is not met. Ol Λ also does not meet the requirements with regard to corrosion b (3i copper and magnesium. These oils represent the critical The standard for the four additional components of the oil according to the invention. The lubricating oils E, G, H and I are examples for the lubricating oils of the invention and are an excellent commercially available synthetic ester lubricating oil in their Performance either the same or superior.

The anti-pollution features have been incorporated into the inventive Ester lubricating oil on the one hand and a commercially available synthetic ester lubricating oil in the Erdco screening test mentioned as well as in the 1.5 Erdco-Bearing-Test comparatively checked. The results are given in Table II below:

Erdco screening test
Deposit note

Erdco-Bearing-Test, Art 1.5 Deposit note

Viscosity increase in %

Increase in total acid number, %

TABLE II

POLLUTION PREVENTION Oil E Oil F Oil G Oil II Oil I 19 40 21 29 31

17 62 23 23 41

21

28

21

1.1 1.4 1.1 1.3 1.3

MIL-L-23699B regulation

80 max.

-5 to +30

2 max.

All lubricating oils composed according to this invention meet the military requirements mentioned. they received even better grades than a commercially available ester lubricating oil, jämlich lube F.

BATH ORIGINAL

20607SH

The lubricating oils C and E, a commercially available, standard lubricant, were tested and compared according to the so-called '410 C l; ainless steel corrosion test ", a corrosion stent on stainless steel. For this test, plates of 25.4 : 152.4 χ 0.31 <3 now made of stainless steel sheet; the steel sheet corresponded to the 410 standard; the specification J ¹ Ir. 5504 for missile cr ^ aterial and had a Brinell hardness of about B76 and a surface quality of 2D. Two of the 'hard disks were set to 0 , Weighed exactly 1 mg and then introduced together with 65 ml of the oil to be divided into a Hickel autoclave. The oil in the autoclave was heated to 260 ° C. and this temperature was maintained for 72 hours. The oil was then allowed to cool to room temperature and 5 ml were withdrawn Determination of the total acid number The autoclave was then heated again to 260 ° C. and the temperature was maintained for a further 72 hours, after which the autoclave was allowed to cool again and the plates were cleaned and weighed them out to the nearest 0.1 mg. The viscosity of the oil at 37, B ⁰ C as well as; the total acid number was determined. The results are given in Table III below.

TABLE III

CORROSIOIi SSICHERH-CIT 1331 STAINLESS STEEL, IiORM 410 260 ° C / 144 h Lubricating oil E lubricating oil C Handelsübl
Ester oil F L ehe s 1. Acceptance,
Weight loss, mg 15th 171 56 2. acceptance,
Weight loss, mg 19th 97 34 Total acid number, 9.55 32.91 16.01

This test shows that the lubricating oil of the present invention has a corrosion resistance for stainless steel Norm 410 is significantly superior to a commercially available oil and a similar oil without tricresyl phosphate.

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206Ό7ΈΠ

From the tests described it can be seen that the invention Lubricating oil excellent oxidation resistance, Has corrosion resistance and pollution prevention. The lubricating oil E meets the requirements of the military regulation HIL-L-23699B of the U.S. Navy and also those of the Pratt / Lihitney Aircraft Regulation 521B. The same goes for for oils G and II.

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Claims (7)

- 16 PA TE NTANSPRU CHE ί1)) Synthetic ester Scliraieröl consisting essentially ^ - "^ of a reaction product of pentaerythritol or trimethylol propane with an organic monocarboxylic acid having 2 - 18 carbon atoms, characterized by proportions of a) about 0.3-5% by weight of an alkyl- or aralkyl-phenylnaphthylamine, whose alkyl radical has 4-12 carbon atoms, b) about 0.3-5 wt .-% of a dialkyldiphenylamine, its ™ alkyl radicals have 4-12 carbon atoms, c) about 0.001-1% by weight of a polyhydroxyanthraquinone and d) about 0.25-10% by weight of a hydrocarbon phosphate, whose hydrocarbon radical has an aryl ring and 6-18 carbon atoms. 2) Synthetic ester lubricating oil according to claim 1, characterized in that it contains about 0.5-2.5% of an octylphenyl - ^ - naphthylamine or -ß-naphthylamine. 3) Synthetic ester lubricating oil according to claim 1, characterized in that it contains about 0.5 - 2.0 Ja of a dioctyldiphenylamine. 4) Synthetic ester lubricating oil according to claim 1, characterized in that it wa et 0.01 to 0.5% of Polyhydroxyanthrachinons contains. 109826 / 15A? 5) Synthetic ester lubricating oil according to claim 1 characterized in that it contains about 0.1 % quinizarine, about 1.5 % t-octylphenyl-ctnaphthylamine, about 1.0 % dioctyldiphenylamine and about 2.0% tricresyl phosphate. 6) synthetic ester lubricating oil according to claim 1, characterized in that the ester base oil is a product of the conversion of pentaerythritol with a mixture of aliphatic acids with about 5 - 10 carbon atoms. 7) synthetic ester lubricating oil according to claim 1, d a d "u rch marked that it as an ester base oil, a product of the conversion of pentaerythritol with significant proportions of isovalerian, Valeric, caproic, heptylic, caprylic and pelargonic acids with an average carbon chain length between and 7. 109826/154?