DEST004914MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: June 5, 1952. Advertised on October 27, 1955

GERMAN PATENT OFFICE

The invention relates to the composition of

Lubricating greases which, in addition to known thickeners, contain trisodium phosphate, which means that their High temperature properties and mechanical resistance can be increased.

It has already been proposed to use salts of low molecular weight acids, such as acetic acid, acrylic acid, Furancarboxylic acid, to combine with the soaps of the usual type serving as thickeners ίο certain properties of the lubricating grease, ζ. B. the Resistance to high temperatures, to improve, to increase the melting point and the lubricating greases to give a higher consistency and a longer lubricant action time.

According to the invention, a content of trisodium phosphate in lubricating greases based on lubricating oil, which as Thickener 5 to 40 percent by weight sodium soaps of saturated fatty acids having 12 to 24 carbon atoms contain, in a wide temperature range, unexpectedly good lubricating properties of the Lubricating grease that is out of proportion to the small amounts of the additive.

A number of known types of greases have been found to be used for thickening Soaps and complexes with oils of high V.-I. (Viscosity index) were poorly tolerated. Because of this such greases were generally made from oils of low V.-I. here. How to take in

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del 'Sehiniermittolindiistrie almost always lubricating oils from a V.-J. of 40 or 50 to avoid this difficulty.

The present invention also enables lubricating oils of high V.-I., ■ / ,. B. from at least 80, preferably about qo to 100 and beyond, to use his good lubricating greases, whereby one is able to produce lubricating greases of high durability, good lubricity at high and running temperatures and a good structure. The lubricating greases according to the invention show an exceptionally good behavior in the spindle test at high speed and high temperature. The duration of the hinge at Toooo was unidr./min. and 149 ° 1000 to 1500 hours or more, while it was only a fraction of these values with the previously known lubrication rates. In addition, the additives used are not expensive and their processing is simple and easy.

Furthermore, the resistance to oxidation of the! '"Cite is made essential by the trinatriine phosphate increases, which is important for high temperature lubricating greases is. The increase in the oxidation resistance wedge is particularly effective for those fats that with soda soaps, in particular with soda soaps of oxy acids, such as oxystearic acid, thickened are. A better dispersion of the soap and a pre-thickening effect is also achieved without the other quality of the fat suffers.

The soap content of the grease is between 5 and 40 percent by weight of the grease, 10 to 30 ° / _u Natriunisifo are generally required for roller bearing lubrication. The soda soaps can be made from all fatty acids or fatty oils with about 12 to 24

C atoms are produced. Saturated oxyacids are particularly preferred.

With the sodium phosphate to be combined soaps must be specially selected to achieve the best results, because the gedickten with the usual oleic or stearic fats 65-135 ⁰ undergo a phase change when they are modified with sodium phosphate. Such fats become too hard on cooling and are therefore not very suitable as lubricants. This drawback is eliminated according to the invention if you use oxy acids, for. B. oxystearic acid, used at least as part of the soap base. Preferably, the oxystearic acid forms at least half of the base of the screen.

This tendency to harden was a) on fats thickened with soda soap of the usual kind without Sodium phosphate addition, b) in fats thickened with soda soap of the usual kind with a content of Trinatriuin phosphate and c) with sodium 12-oxystoarate Thickened fats with a content of trinatriine phosphate were investigated.

A brass cylinder λ'οη 6.4 cm in length and 9.5 mm Diameter was filled with the fat and placed upright in a brass pedestal. From every sample was after that in the magazine "Institute Spokesman". of October 1947 on page 6 of the procedure described the »micropenetration« determined. On that the cylinder was exposed to the respective test temperature in an oven for 1 hour, then taken out and allowed to cool to room temperature. Then the micropenetration was done again determined by the cooled fat. The results are given in Table I.

Table I.

example Rope foundation Na ₃ PO ₄
Weight percent Viscosity of the oil
cSt at 37.8 ° V.-I. Temperature,
at which the value
for micro-penetration
had fallen by 25 ° / ₀
⁰ C A.
B.
C.
D.
IC
1-'
G
II
.1 Ki'ib seed oil
Stearic acid
the same
desg!
the same
the same
the same
12-oxystearic acid c
the same O
O
O
3.9
1.75
2.9
2.3
3.0
4.5 65
69
108
69
108
108
108
108
108 45
45
45
45
45
45
45
45
45 127
124
104
71
88
under 66
85
146
138

ICs turned out to be those with 12-oxystearic acid soap Thickened fats II and J containing trisodium phosphate are the greatest in terms of hardening Exhibited heat resistance.

Example K

ICs was a fat made from 22 parts by weight of stearic acid, 69.6 parts of mineral oil (viscosity 70 cSt at 37.8 "; V.-l. 45), 4.5 parts of sodium hydroxide in aqueous solution and 9.1 parts of hydrated trinatriine phosphate ( Na., PO ₁ , ■ 12 H ₂ O) or 3.9 parts

of anhydrous salt. The fat was used to form the soap and evaporate the water and dehydrating the sodium phosphate. The product showed very good resistance to oxidation and remained effective for an exceptionally long time in the high speed spindle test.

The spindle test at high speed is used to determine the high temperature behavior of Lubricating greases. It is through the "National Lubricating Grease Institute" and the "Annular-Bearing Engineering Committee of the Anti-friction Bearing Manufacturers Association «has been published,

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and described inter alia in the "Institute Spokesman", December 1950, p. 7. The method consists in using a Norma-Hoffman ball bearing No. 204 with 10,000 rev / min. at 149 ⁰ until it no longer works. The usual sodium soap greases soon turn dark and very hard during this test. This has three main causes: the oxidation of the fat, the evaporation of the mineral oil from the fat and the leakage of oil from the bearing due to phase separation.

As mentioned, highly purified mineral oils are best suited for high-temperature greases, as they have the greatest resistance to oxidation at high temperatures, low volatility and a high V.-I.

own. In addition, such fats must also contain oxidation inhibitors. According to the invention added trisodium phosphate now acts as a strong antioxidant and also reduces

the excretion of the oil at high temperatures. This prevents the manufacture of using sodium soaps thickened fats from lubricating oils of high V.-I. enables.

In the experiments described above, it has been found that there is a direct relationship between the ^{lubrication time of a grease in the ball bearing, measured in the spindle test at 149 0,} and the time within which the same grease, when exposed in an oven at the same temperature, is down to one Micro-penetration of 5 hardened. By means of a simple static determination of the micro-penetration, a large number of additives can be checked to see whether they increase the oxidation resistance of roller bearing greases. This test method can be referred to as the »fat hardening test. Table II contains the compositions and test results for several high temperature greases.

Table II. Composition and test values for high temperature greases

Composition, weight percent

Stearic acid

Sodium hydroxide

Trisodium phosphate *)

mineral oil

Viscosity cSt at

37.8 ° = 70.0 V.-I. 45

98.9 ° = 15.8 V.-I. 45

37.8 ° = 62.8 V.-I. 80

37.8 ° = 146.1 V.-I. 80

37.8 ° = 32.1 V.-I. 95

37.8 ° = 119.0 V.-I. 95

Phenyl-a-naphthylamine

Test values

Mineral oil, viscosity at 37.8 ° cSt

Free alkali,%

Phase separation at 149 ⁰ (° / ₀ oil loss **)

ASTM dropping point, ⁰ C

Walk penetration at 25 ° mm / 10

Walk penetration after 10,000 impacts ***) ....

Fat hardening test at 149 ⁰

Hours to micro-penetration 5

Bold color at the end of the exam

Spindle test (10,000 rev./min., 149 °), hours

*) Expressed as anhydrous salt (Na ₃ PO ₄ ).

**) 185 g of fat in a galvanized sieve cone of 0.589 mm mesh size, 100 hours at 14g ⁰ ***) Carried out at a shear rate of 2500 / sec.

K L. M. N O 22.0 17.0 22.5 19.5 20.5 4.5 3.1 4.6 4.0 3.9 3.9 0.4 3.7 2.0 69.6 79.9 72.5 43.6 - - - 28.2 - - - - - 29.1 Z Z Z Z 43.5 - - - 1.0 1.0 70 70 70 108 108 0.8 0.15 0.35 0.6 0.8 1.7 25.2 - · 3.7 8.7 222 201 213 221 221 300 3OO 305 290 275 335 265 327 520 290 39 ° 1160 1550 yellow black Brown red-brown dark Brown 480 288 none 1140 1520 values

21.8

4.2 2.5

7.0

63.5

1.0

108 0.9

10.7

270 338

1030 dark brown 1090

This table shows the following:

i. A trisodium phosphate content increases both spindle life and hardening time of the grease at high temperatures (greases K, L, M).

2. The combination of trisodium phosphate with Phenyl-a-naphthylamine leads to an extraordinary improvement in the oxidation resistance, what in the particularly high values for the spindle service life and the hardening time of these greases

509 577/133

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expresses. The particularly good one is noteworthy Composition of the fat with an oil base from the V.-I. Ko (fats N, O).

3. Even when using a base oil from a V.-I. of 95 is due to a content of trisodium phosphate ' and phenyl - «- naphthylamine still show a very considerable increase in both of these parameters achieved (see fat I and P).

A preferred manufacturing method, which however does not form part of the present invention, is that! you first heat the fatty acid together with the same amount of mineral oil in a fat kettle with a steam jacket to about 95 ", then add caustic soda, expediently as a solution of 50" Be, the soap is dehydrated by further heating, then further heated to 150 ", then the phosphate and finally adding the remaining mineral oil. [at this time, oxidation inhibitors or other additives are added as desired. Then, the Ee.lt with continuous stirring is cooled to about 93 ^0, and filled directly into shipping containers.

The beneficial effect of trisodium phosphate on phase separation of the fat is shown in Table II clearly.

The effect of increasing the trisodium phosphate additive on the rate of oxidation, measured by the Eett hardening test, is shown in Table 111. Four fats were obtained by dispersing sodium stearate in a mineral oil with a viscosity of 108 cSt at 37.8 'and one V.-I. manufactured by 80. All samples contained 1 ° / ₀ Phenyla naphthylanrin-.

When the values in Table III below are plotted, it is observed that the hardening time of the fat up to a micropenetration of 5 practically linear with the percentage of the Sodium phosphate increases, from 700 hours for sample Q (blank) to 2150 hours at Fat T.

Table III

Effect of the phosphate content

on the rate of oxidation of fats *)

fat Q
(empty) R. S. T Trisodium phosphate, Ge
weight percentage 1.0 2.0 4.0 Results of the
Fat hardening test Hours to the mic
penetration 5 700 975 1550 2150

Table IV

*) The fats ° j _a Na stearate in Mineral oil (viscosity contain about 20: io8 cSt at 37.8 °, V.-I. = 80) is dispersed.

The quality of the fat, i.e. H. producing the desired consistency with a minimal content of thickeners, is considerably improved by the invention.

The greases produced by this process also have better extreme pressure properties.

A number of fats have been made from 12-oxystearic acid and an SAE 30 mineral oil having a viscosity of about 146 cSt at 37.8 ° and about 80V.-I. manufactured. Various amounts of trisodium phosphate from ο to 3.5% were added. The received Values are shown in Table IV.

fat

Composition, weight percent

12-O.xystearic acid (*)

Sodium Sulphonate 65:35

• ₅ sodium hydroxide (dry)

SAE-30-Ö1

Test results

Free alkali (of soap), ° / ₍₎

ASTM walk penetration at 25 ° mm / io
Timken test, load capacity, kg .. ..

Bi

C-i D-i 15.O 15.O 1.5 1.5 1.9 1.9 i, 8 2.55 79.8 79.05 0.06 0.03 269 259

Egg

F-i

324 at 6.8 insufficient 15.0

80.3

0.04
245

not determined

I5, o

3.4 78.2

ncutr. 325

15-0 1.5

! .9

3.6 78.0

♦) Relationship between soap and oil.

In these experiments, all the variable quantities, except for the sodium phosphate content, became constant hallen, as well as the manufacturing process. You can see that the quality with a trisodium phosphate content from 1.3 to 2.55% »was in the best. The Phosneutr.

337

at 15.0 it is sufficient!., at 17.3

itngcnügd.

The phate content varied from about 0.5 to 1 equivalent (0.167 to 0.333 M ° l) of phosphate per mole of soap.

It should be noted that the grease F-I has a sufficient load-bearing capacity at 15 kg in the lubricant tester after Timken showed a value that is worth the

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Approaching standards for high pressure lubricants, ζ. Β. the lead naphthenate greases, which have a load capacity of 15 to 19.5 kg. Grease R with 2.5% Na ₃ PO ₄ had a load capacity of 11.4 kg, while greases usually thickened with soda soap failed in the Timken tester at 6.8 kg.

The optimal addition of phosphate appears to be about 2 to 4 ° / ₀ anhydrous salt. The hydrated salt can be / is used to 20 ° ₀ in amounts of from about. 2 Slightly lower lower limits to 0.5 ° / ₀ and upper limits are up to about 10 ° / ₀ of the anhydrous salt can be used with good results, for example.

Although the invention is particularly useful for fats based on mineral oils with a V.-I. at 80 proven, it can also be applied to lubricating greases that have mineral oil bases with a V.-I. from contain at least 45, as well as lubricating greases based on synthetic oils, such as silicone polymers, z. B. polyphenyl-methyl-siloxane, synthetic ether, e.g. B. n-butyl-polyethoxybutane, polymerized Hydrocarbons, e.g. B. polyisobutylene, or preferably synthetic esters, such as D1-2-ethylhexyl sebacate, be applied.

Example Q

25 percent by weight of sodium stearate was mixed with a small amount of a mineral lubricating oil (viscosity = 146 cSt at 37.8 °, V.-I. = 80) to the complete Mixed dispersion. Then the mixture was heated to 205 ° and at 60 percent by weight Di-2-ethylhexyl sebacate is added. The hot mixture was then poured out and allowed to cool to processing temperature. It then turned to kneaded into a smooth fat.

Example R

A second sample of the same fat became 3.8% of a solution during manufacture at 210 ° of trisodium phosphate was added and the mixture was dehydrated prior to the addition of the sebacic acid ester. After cooling and kneading, a smooth fat was obtained. These two fats were made subject to the standard tests described above. The results can be found in Table V.

The values given in Table V show that the sodium phosphate also has a considerable effect here Improves the consistency for a given soap content. The phosphate-free fat (empty experiment Q) was extremely soft and had high penetration, while the phosphate-containing one Fat had an excellent fat structure. When the phosphate-free fat of the high temperature of the When subjected to oven testing, it leaked from camp, darkened, and hardened quickly. After. At the same time, the phosphate-containing fat showed little change.

You can use the usual additives such. B. Oxidation inhibitors, extreme pressure additives, adhesives, metal Use deactivators and the like in the usual quantities, without affecting the other properties of the fat

Table V

Lubricating greases
based on synthetic esters

fat

Composition, weight percent

Sodium stearate

Mineral oil*)

Na ₃ PO ,, (anhydrous)

Di-2-ethylhexyl sebacate

Test values
Micro-penetration

Fat hardening test at 149 °
after 100 hours in the oven

Micro penetration <5

Fat color black

Loss, weight percent .. 60

*) Viscosity at 37.8 ° = 146 cSt, V.-I. = 80.

25.0
15.0

60.0

290

25.Ο

15.0

3.8

56.2

55

31
pale yellow

particularly to influence. Pheny! Naphthylamines are In connection with trisodium phosphate particularly effective antioxidants.

Claims (5)

PATENT CLAIMS: 1. Lubricating greases based on mineral or synthetic lubricating oils with a content from 5 to 40 percent by weight of soda soaps of saturated fatty acids with 12 to 24 carbon atoms as a thickener, characterized by a content of 0.5 to 10 percent by weight anhydrous trisodium phosphate based on the total weight of the grease. 2. Lubricating greases according to claim 1, characterized in that, that the thickener is an oxystearic acid soap, preferably 12-oxystearic acid soap, is. 3. Lubricating greases according to claim 1 and 2, characterized in that the base oil is a mineral Lubricating oil with a viscosity of 20 to 1100 cSt at 37.8 ° and a viscosity index of at least 45 is. 4. Lubricating greases according to claim 1 and 2, characterized in that the base oil is a synthetic Lubricating oil, such as a silicone polymer, z. B. polyphenyl-methylsilicone, a synthetic ether, e.g. B. n-butyl-polyethoxybutane, a polymerized Hydrocarbon, e.g. B. polyisobutylene, or a synthetic ester such as di-2-ethylhexyl sebacate, is. 5. Lubricating greases according to claim 1 to 4, characterized by a further content of 0.1 to ι percent by weight phenyl-ct-naphthylamine. 120 Referred publications:
German patent specification No. 667 708.