DE1075777B - Mineral oil-based lubricating grease with a content of metal soaps of higher fatty acids - Google Patents

Description

GERMAN

The invention relates to mineral oil-based lubricating greases with a metal soap content of higher fatty acids including wool fat fatty acids.

There are known lubricating greases which contain wool fatty acids or their soaps as a component. In the case of lubricating greases containing calcium soaps, it is known to use wool fatty acids as stabilizers to use. It is also known to use sour wool fat and greases Producing zinc dust, at least a portion of the mixture forming a zinc soap.

There are also known lubricating greases, in addition to mineral oil and / or synthetic oil and an oxidized aromatics-rich petroleum fraction a small amount of alkali, alkaline earth, aluminum and / or Zinc soaps contain various fatty acids including those made from animal fats Origin, such as tallow, Schtnalz oil, bone oil, neat oil, wool fat or horse fat oil.

There is also a mineral oil-based lubricating grease known which contains alkali and or or have alkaline earth soaps of lanopalmic acid. Wool grease contains a small amount of lanopalmic acid. However, the same effect cannot be achieved with wool fat soaps as with soaps made from lanopalmic acid achieve.

The invention aims to provide a mineral oil-based lubricating grease containing Metal soap that has good storage and usage stability and its lubricating quality over a long period Range of working conditions and also in the presence of excess water reserves.

It has been found that such a grease can be used with a certain content of soaps of wool fat fatty acids and other higher fatty acids with certain metals, in compliance certain molar ratios between the metal components can be obtained.

The grease according to the invention is characterized by a content of a mixture of soaps, in which the acid components make up about 15 percent by weight to about 80 percent by weight Wool fatty acids and the remainder of one or more aliphatic acids with at least about There are 12 carbon atoms per molecule, one of the Metal components are lithium and at least one other metal component is made up of calcium, strontium, Barium or zinc, with the molar ratio of lithium to calcium between about 27: 1 and about 4: 1, the mole ratio of lithium to strontium between about 42: 1 and about 2.8: 1, the The molar ratio of lithium to barium between about 33: 1 and about 3: 1 and the molar ratio of

with a content of metallic soaps

higher fatty acids

Applicant:

Socony Mobil Oil Company, Inc.,
New York, NY (V. St. A.)

Representative: Dr. E. Wiegand, Munich 15,
and Dipl.-Ing. W. Niemann, Hamburg 1, Ballindamm 26, patent attorneys

Claimed priority:
" _N V. St. v. America November 20, 1956

Richard Augustine Butcosk, Uniondale, N.Y. (V. St. A.), has been named as the inventor

Lithium to zinc between about 30: 1 and about 5: 1 lies.

The lubricating greases according to the invention are characterized by a combination of advantageous properties from, which cannot be obtained with the known lubricating greases described.

It was initially believed that calcium soaps when used in the lithium greases described herein are present, destroy the water resistance of such lubricating greases. However, it is It has been found that small amounts of calcium soaps add to lithium greases Giving improvement instead of making it worse. Upon further investigation, the effect of calcium soaps it was surprisingly found that calcium soaps have the characteristic of water resistance do not destroy. The earlier assumptions may be due to the fact that resulted in insufficient dehydration due to the use of too low temperatures.

Wool fatty acids are known in the art; they are, for example, in a paper by E. S. Lower described in detail in "Industrial Chemist" in the March, May and October 1947 editions.

909 730/447

Physical properties of wool wax fatty acids and a typical wool fat fatty acid product are given in the table below.

Physical properties of wool fat fatty acids

Humidity, %

Unsaponifiable,%

Saponifiable,%

Free fatty acids such as oleic acid,%

Free neutral fat,%.

Saponification number

Iodine number

Titer ⁰ C

area

Ibis 5

3 to 7

70 to 98

70 to 95

Obis 5

120 to 190

20 to 50

40 to 45

Typical

95

84

no
170

25 to 34
40 to 43

The table above is particularly indicative of wool fat fatty acids such as those in Great Britain be generated. Lately in the US, lanolin alcohols and cholesterol have been around from Degras (wool fat) extracts wool fat fatty acids from something different physical and chemical Properties are available and these are the preferred material.

USA.-wool fat fatty acids, extracted

as a by-product of lanolin alcohol and

Cholesterol production

Acid number 105 to 125

Saponification number 140 to 165

Iodine number (Hanus) 10 to 20

Titer, ⁰ C 50 to 53

Acetyl number 45 to 75

Water, ° / o 1 to 3

Ash, Vo 0.2 to 0.6

Suitable aliphatic acids with at least 12 carbon atoms per molecule are stearic acid, Oxystearic acids, such as 12-oxystearic acid, oleic acid, Palmitic acid, oxypalmitic acid, myristic acid, oxymyristic acid. It can also contain fatty substances which contain substantial proportions of the aforementioned acids in the production of the lubricating grease according to of the invention can be used. Examples of such substances are vegetable and animal fats and oils and fish oils and their hydrogenation products, stearin, hydrogenated tallow fatty acids, hydrogenated soybean fatty acids and partially hydrogenated marine animal oils, vegetable oils and animal oils. Preferably are used together with the wool fatty acids stearic acid, palmitic acid and myristic acid. A particularly excellent lubricating grease is made with balanced proportions of wool fat fatty acids, Obtained stearic acid and oxystearic acid.

In making the greases according to the invention, the composition is the acid component the lithium soap is critical. It is found that the desired property of water resistance is obtained only when about 15 to 80 percent by weight of wool fat fatty acids are used, while the remainder of the acid components consists of aliphatic acids of the type described above. Excellent grease compositions are obtained when the acid components are about 25 to 50 percent by weight wool fat fatty acids and the remainder include aliphatic acids of the aforementioned type. When lithium soaps 5. Of wool fat fatty acids in the corresponding lithium-based grease compositions completely absent, the latter have insufficient water resistance properties. Self if lithium soaps made from wool fat fatty acids together with other lithium soaps such as lithium stearate, are present but in insufficient proportion, the resulting compositions have become proved unsatisfactory. The other hand is a grease that only contains lithium soaps of wool fat fatty acids are inferior to the greases according to the invention. One such Grease solidifies with prolonged storage, i. i.e. the grease is too firm in consistency, so that it does not lubricate properly in use.

ao The finished lubricating greases according to the invention can react somewhat acidic or somewhat basic or be neutral. The finished greases can e.g. B. contain an amount of acid that is up to 0.5 percent by weight Oleic acid is equivalent, or they can e.g. B. contain an amount of alkali up to is equivalent to 0.2 weight percent lithium hydroxide.

The lithium grease compositions according to the invention also contain small but critical ones Amounts of calcium, strontium, barium and / or zinc soaps. If calcium soaps are used, the molar ratio of lithium to calcium is said to be between about 27: 1 and about 4: 1, with molar ratios within the range of 14: 1 to 9.5: 1 are preferred. When using strontium soaps the lithium to strontium molar ratio should be about 42: 1 to about 2.8: 1; preferably the molar ratio is in the range from 14: 1 to 4.7: 1. Correspondingly are included Mixtures of lithium and zinc soaps have molar ratios between about 30: 1 and 5: 1, preferably in the range of 15: 1 to 7.5: 1. When barium soaps are used, the molar ratio of lithium to barium should be between about 33: 1 and about 3: 1 lie; preferably molar ratios in the range 16: 1 to 13: 1 are used. if two, three or all four soaps of the metals calcium, strontium, barium and zinc are used, that is The molar ratio of lithium to each of these metals is between about 14: 1 and about 4.7: 1.

The total amount of soaps is also important for the properties of the lubricating greases according to the invention Meaning. The soaps should suitably be about 5 to about 30 weight percent and preferably about 7 to represent about 20 percent by weight of the finished greases.

Preformed soaps can be incorporated into the oil during the manufacture of the lubricating greases; the soaps can, however, also be placed in the oil on the spot.

forms are. It can contain a wide variety of lithium, calcium, strontium, barium, and zinc compounds used in the manufacture of the soaps, e.g. B. lithium compounds in the form of hydroxide, carbonate and hydrids. In general, however

Lithium hydroxide preferred. Usable calcium compounds are e.g. B. the hydroxide, oxide and Carbonate, with the hydroxide being preferred. Suitable strontium compounds are the carbonate and the hydroxide octahydrate, the latter being preferred. Suitable barium compounds are

the hydroxide, and the hydroxide octahydrate (Ba (OH.) ₁ , - 8H 2 O), the latter being preferred. As zinc compounds, for. B. used: zinc oxide, carbonate and stearate (previously formed); the latter compound is preferred.

The mineral oil component of the lubricating greases according to the invention can have different characters. The oil component is characterized by a SUS viscosity greater than 1 at 37 ° C and generally around 60 to about 6000 at 37 ° C. The oil can be naphthenic or paraffinic in character do. Suitable oils are e.g. B. a naphthenic mineral oil with an SUS viscosity of 70 at 37 ° C and a solvent refined naphthenic oil with an SUS viscosity of 80 at 37 ° C.

The preparation of lubricating greases according to the invention is illustrated below by means of a few examples explained in more detail.

example 1
Lithium-calcium lubricating grease

All fatty substances, wool fatty acids and, for example, hydrogenated tallow fatty acids, and 30 to 40% of the total amount of the mineral oil are placed in a suitable grease kettle. The ratio of wool fat fatty acids to stearic acid (the main component of hydrogenated tallow fatty acids) is 3: 8. The resulting mixture is heated to about 60 to 71 ° C and then the required proportion of lithium hydroxide monohydrate dissolved in water is added. This is followed by the addition of washing water. Dry Ca (OH) _{2 is then} added; the molar ratio of lithium to calcium is 14: 1. The mixture thus obtained is then heated to 193 to 199 ° C. for a period of 1 to 3 hours. At this point the remainder of the mineral oil used in the preparation of the grease composition is added and the entire mass is reheated to 199-205 ° C over a period of 1 to 2 hours. The resulting liquid product is drained from the grease kettle into pans and allowed to cool to room temperature (21-27 ° C). Cooling generally takes 2 to 10 hours. The chilled grease blocks thus obtained are rolled into a buttery product of the desired penetration.

Example 2
Lithium-S trontium lubricating grease

The procedure for producing a lithium: strontium lubricating grease is essentially the same as in Example 1. In this case, however, lithium hydroxide and strontium hydroxide are dissolved in water and added at the same stage of production. There is therefore no addition of a dry hydroxide as when using Ca (OH) ₂ . The ratio of wool fat fatty acids to stearic acid is again 3: 8; the molar ratio of lithium to strontium 14: 1.

Example 3
Lithium barium grease

The preparation of a lithium barium grease is carried out in the same way as • that of the lithium strontium grease according to ^ Example 2. The ratio of wool fat fatty acids to Stearic acid is 3: 8, the molar ratio of lithium to barium 16: 1.

Example 4
Lithium zinc grease

The production method for a lithium-zinc grease is the same as that for the lithium-calcium grease according to Example 1 with the following modification: The LiOH · H ₂ O is in

ίο dissolved water and the zinc stearate immediately afterwards added. The molar ratio of wool fatty acids to stearic acid is 3: 8, the molar ratio of Lithium to zinc 15: 1.

Lubricating grease compositions according to the invention are subjected to various tests have been to determine their properties in storage and in use under conditions that resemble those during their actual use.

One of these tests concerns the processing of lubricating greases with 10% by weight of water in one Motor-Matik device for 100,000 double strokes. This test is a measure of the mechanical stability of the Grease when exposed to water and is in Military Specification MIL-G-IO 924, amendment 2.

Another test measures the effectiveness of the grease in preventing corrosion of metal parts to which the grease is applied. This is the CRC-Free-Water-Corrosion-Test, which is described in the Military Specification MIL-G-25013A. The 4,3,2,2 to 4,3,2,2,4 test is known as the bearing protection test.
A third test measures the stability of the grease under severe storage conditions. This is the accelerated oven test. In the accelerated oven test, a sample processed 60 times is placed in a Coors No. 0 crucible of low shape. It is stated, a ^1/2-scale cone penetration; the value thus obtained is taken as the initial penetration. A fresh sample of the grease (unprocessed) is placed in another pan (the same size) and the pan is left in an oven at 71 ° C for 3 days.

At the end of the three-day period, the latter crucible is removed from the furnace and cooled to 25 ° C. The V2 scale cone penetration is determined again on the sample treated in this way; the so value obtained is taken as the final penetration. The degree (%>) of hardening of the grease under these accelerated conditions is calculated as follows:

% Hardening =

Difference between start and
End penetration X 100

At the beginning of an entetration

The correlation between the percentage of hardening and the actual storage conditions leads to the following scale:

40% and higher = excessive hardening

if stored for 3 to 12 months
31 to 40% = sufficient

15 to 30% = excellent to good

Results of the tests carried out with typical lubricating greases according to the invention are shown in FIG Table I below.

Table I.

Physical properties of greases made with lithium soaps
are made in a mixture with other metal soaps.

lithium
barium

lithium
zinc

lithium
strontium

lithium
Calcium

lithium

Calcium

strontium

Molar ratio of lithium to other metal ...

Wool fat fatty acids

Stearic acid

Mineral oil (SUS viscosity of 500 at 37 ° C),

solvent refined

Lithium hydroxide (LiOH- H ₂ O)

Barium hydroxide (Ba (OH) ₂ )

Strontium hydroxide (Sr (OH) ₂ 8 H ₂ 0)

Lime flour (Ca (OH) ₂ )

Zinc stearate

Penetration (not drummed / drummed)

50,000 X Vie "dry kneader test

100 000X ¹ Ai "with 10% H ₂ O,

Accelerated oven test, 3 days at 71 ° C curing

ASTM dropping point

CRC Free Water Corrosion Test (14 days - distilled water)

The results given in Table I show that solid greases have a good shelf life using wool fat fatty acids and stearic acid and with a combination of lithium and a metal from Group II of the Periodic Table, having an atomic weight between 40 and 137 can be produced. All of these greases have excellent resistance to Breakdown by shear action under both wet and dry conditions. It is Also note that all of these greases have high melting points above 177 ° C. A consideration All of the results show that the lithium-calcium grease can be described as exceptionally good.

Further lubricating greases of those considered here Types are shown in Table II. Here the oil carrier has a lower viscosity than with the lubricating greases as shown in Table I. In this case too, the grease compositions have excellent properties.

Table II

16: 1
3.00%
8.00%

87.00%
1.60%
0.40%

256/277
337
342
32%
188 ° C

15: 1
3.00%
8.00%

85.80%
1.60%

1.60%
259/283
375
361
22%
181 ° C

14: 1
3.00%
8.00%

86.68%
1.60%

0.72%

253/292
281
335
29%
214 ° C

14: 1 3.00% 8.00%

87.20% 1.60%

0.20%

268/288

307

340

19% 188 ° C

each 14: 1 3.00% 8.00%

86.68% 1.60%

0.72% 0.20%

280/300 305 362 29% 188 ° C

Wool fat fatty acids

Stearic acid (hydrogenated tallow fatty acid)

LiOH-H ₂ O

Lime flour

Mineral oil (SUS viscosity
of 100 at 37 ° C),
solvent refined ...

Penetration (not drummed / drummed)

50,000 X Vie "dry kneader test

100,000 X ¹ Zi ' with 10% H ₂ O

Accelerated oven test
(4 days at 71 ^° C.) hardening

ASTM dropping point

Molar ratio of lithium to calcium 4: 1 I 14: 1

- passed passed passed passed

As indicated above, grease compositions of the type contemplated herein can be preformed Soaps are made. Standard procedures can be used when looking from makes use of the preformed soaps. The greases given below are based on the following Way made. The wool fat fatty acid soap is made with about 30 percent by weight of the total mineral oil mixed. The mixture is heated to about 205 ° C and the resulting mixture is cooled. the Common aliphatic acid soap (i.e., the stearate) is made with about 30% of the total mineral oil mixed and this mixture heated and cooled in the same way. The two soap mixes are then combined with each other and with the rest of the oil. The mixture is heated to about 205 ° C. The end product is cooled to 21 to 27 ° C and then to a product with the desired Penetration rolled. Greases so prepared are shown in Table III below.

Table III Preformed Soaps

3.85%

8.00% 1.25% 0.50%

86.40% 265/272

259 288

36% 162 ⁰ C

3.85%

8.00% 1.59% 0.20%

86.36% 276/282

240 271

29% 181 ° C molar ratio of

Lithium to calcium

6: 1 i 7: 1

Lithium stearate

Lithium soaps from wool fat fatty acids ... -

Calcium stearate

Calcium soaps from wool fat fatty acids

Penetration (not drummed / drummed)

50000XVi ₀ "dry

-65 kneader test

100 000 X ¹ U " with 10%

Water -

Accelerated oven test

(3 days at 71 ° C) curing
.70 ASTM dropping point

8.9% 2.3%

The results, shown in Table III, show that the two greases are excellent Possess properties. Exceptionally good in terms of shelf life is the grease that Contains lithium stearate and calcium soaps from wool fatty acids; the hardening is only 18%.

The lubricating greases according to the invention can also contain other known additives. For example The lubricating greases can use antioxidants, such as amines, phenols, sulfides, and the lubricity ίο improving agents such as free fat, free fatty acids, esters of alkyl and / or aryl acids, sulfurized Contains fats, lead soaps. These additives worsen the lubricity value of the here under consideration drawn greases are not. The amount of such additives which the lubricating greases according to the invention may be incorporated is about 0.01 to less than 10 weight percent, and preferably 0.1 up to 5.0 percent by weight.

Lubricating greases according to the invention are general for use in vehicles, in particular Motor vehicles, suitable. They are also excellent aircraft or industrial greases.

Claims (10)

Patent claims: 1. Mineral oil based grease containing metallic soaps of higher fatty acids lent wool fat fatty acids, characterized by a content of a mixture of soaps in which the acid components are about 15 to about 80 percent by weight from wool fat fatty acids and the remainder from one or more aliphatic acids with at least about 12 carbon atoms per molecule, one of the metal components Lithium is and either (1) just another metal component from the group calcium, strontium, Barium or zinc is present, the molar ratio of lithium to calcium being between about 27: 1 and about 4: 1, the molar ratio of Lithium to strontium between about 42: 1 and about 2.8: 1, the molar ratio of lithium to Barium between about 33: 1 and about 3: 1 and the molar ratio of lithium to zinc between about 30: 1 and about 5: 1, or (2) more than one other metal component selected from the group Calcium, strontium, barium or zinc is present, the molar ratio of lithium to each of the other metals is between about 14: 1 and 4.7: 1. 2. Lubricating grease according to claim 1, characterized in that the wool fat fatty acids are about 25 make up 50 percent by weight of the total acid components. 3. Lubricating grease according to claim 1 or 2, characterized in that the aliphatic acids consist of stearic acid, oxystearic acid or a mixture of stearic acid and oxystearic acid. 4. Lubricating grease according to one of claims 1 to 3, characterized by the content of a mixture of lithium and calcium soaps, the acid components of these soaps being about 33 percent by weight consist of wool fat fatty acids and about 67 percent by weight stearic acid and that Lithium to calcium molar ratio is between about 14: 1 and 4: 1. 5. Lubricating grease according to claim 1, characterized by the content of about 8 percent by weight lithium stearate and about 3 percent by weight calcium soaps of wool fat fatty acids, the molar ratio from lithium to calcium is about 6: 1. 6. Lubricating grease according to claim 1, characterized by the content of a mixture of lithium and zinc soaps, the acid components of these soaps being about 33 percent by weight Wool fat fatty acids and about 67 percent by weight stearic acid and the molar ratio from lithium to zinc is about 15: 1. 7. Lubricating grease according to claim 1, characterized by the content of a mixture of lithium and strontium soaps, the acid components of these soaps being about 33 percent by weight Wool fat fatty acids and about 67 percent by weight stearic acid and the molar ratio from lithium to strontium is about 14: 1. 8. Lubricating grease according to claim 1, characterized by the content of a mixture of lithium and barium soaps, the acid components of these soaps being about 33 percent by weight Wool fat fatty acids and about 67 percent by weight stearic acid and the molar ratio from lithium to barium is about 16: 1. 9. Lubricating grease according to claim 1, characterized by the content of a mixture of lithium, Calcium and strontium soaps, the acid components of these soaps being about 33 percent by weight of wool fat fatty acids and about 67 percent by weight of stearic acid and the molar ratio of lithium to calcium and lithium to strontium is each about 14: 1. 10. Lubricating grease according to one of claims 1 to 9, characterized in that the proportion of Mixture of soaps is about 5 to 30 percent by weight, based on the total grease. Considered publications: German Patent Nos. 943 487, 832 787; U.S. Patent No. 2,514,331; British Patent No. 693,744; B ο u e r: Manufacture and Application of Lubriating freates (1954), p. 362. © 909 730/447 2.60