DE2235098C2 - Grease - Google Patents

Description

a) essentially a lithium soap of a hydroxy fatty acid with 12 to 24 carbon atoms,

b) a monolithium salt of boric acid and optionally

c) a lithium salt of a second hydroxycarboxylic acid having 3 to 14 carbon atoms in the molecule

contains, wherein the hydroxyl group of component c is bonded to a carbon atom, which is not more than 6 carbon atoms away from the carboxyl group, according to patent 21 57 207, characterized in that components a and b in the grease in a weight ratio of hydroxy fatty acid to boric acid such as 3: 100 are included, and if component c is also included in the lubricating grease, the weight ratio of the second hydroxycarboxylic acid to boric acid is 0.1 to 10.

2. Lubricating grease according to claim 1, characterized in that it is the lithium soap as component a which contains 12-hydroxystearic acid.

3. Lubricating grease according to claim 1, characterized in that it a! S component c is a lithium salt which contains salicylic acid

4. Lubricating grease according to claim 1, characterized in that it is the lithium salt as component c which contains lactic acid.

5. Lubricating grease according to claim 1, characterized in that it is the lithium salt as component c which contains parahydroxybenzoic acid »

The invention relates to a lubricating grease composition, which consists largely of a lubricating oil and to about 2 to 30% by weight. calculated on the total mass, consists of a thickening system, which is essentially lithium soap of a hydroxy fatty acid with 12 to Contains carbon atoms and a monolithium salt of boric acid, according to patent 21 57 207.

This is an improved lithium soap grease of the best quality with excellent Properties such as a high dropping point, excellent resistance to oxidation, a long Lubrication duration and water resistance.

As such, lithium greases are known and have been used extensively for many years. The lithium soaps are used for such as fats ^v erdickungsmittel are usually prepared by reacting Liihiumhydroxyd or other suitable lithium base with a conventional high molecular weight acid or more acids. British patents 7 17 453 and 10 30 700 are mentioned as general prior art. The main advantages of lithium greases are their high water resistance and the ease of dispersing these soaps in all types of oil-based lubricants. Fats are particularly useful are made from lithium hydroxystearate as soaps of hydroxystearic acid and related hydroxy fatty acids have proven to be more mechanically stable than the corresponding soaps of ordinary

Fatty acids.

There are numerous uses for fat compositions that require a high dropping point required, such as when lubricating the bearings of tractor engines. Camps

ίο such tractors should be used for a period of more than three years working without maintenance, being there

Temperatures up to 121 ° C inside the warehouse

may occur.

According to the invention, the grease is for

υ mostly from a lubricating oil and up to 2 to 30% by weight, calculated on the total mass, from a thickening system that

a) essentially a lithium fatty acid of a hydroxy fatty acid with 12 to 24 carbon atoms,

b) a monolithium salt of boric acid and optionally

c) a lithium salt of a second hydroxycarboxylic acid having 3 to 14 carbon atoms in the molecule

contains the hydroxyl group of component c being bonded to a carbon atom which is not is more than 6 carbon atoms from the carboxyl group, according to patent 21 57 207. The invention is characterized in that components a and b in the grease in a weight ratio of Hydroxy fatty acid to boric acid such as 3: 100 are included and, if the lubricating grease also contains component c included is the weight ratio of the second

J5 hydroxycarboxylic acid to boric acid is 0.1 to 10.

In the American patent 29 40 930 is already stated that fats with a high dropping point (260 ° C or higher) from mixtures of Monocarboxylic and dicarboxylic acids are produced can. When making the in the mentioned However, it was necessary to use glycol in addition to the fats described in the patent. The presence of Glycol, however, is undesirable because it makes the fat sensitive to oxidation and the water-resistant ability of the grease in various areas of application lowered to an undesirable extent. The invention now enables the production of fats with high Dropping points from hydroxy fatty acids without the need to add glycol.

American patent sections 32 23 633 and 32 23 624 describe the production of fats with a high dropping point from a 3-component mixture of acids. The presence of fatty acids Salts with 2 to 4 carbon atoms in the molecule, the represent an essential component of such fats, however, it is often undesirable because such fats have a tendency to harden the surface on standing demonstrate.

Those for the preparation of the fats according to the invention

The hydroxy fatty acid used has about 12 to 24 or more, but preferably about 16 to 20 carbon atoms and is preferably a hydroxystearic acid, for example 9-hydroxy, 10-hydroxy or 12-hydroxystearic acid, preferably the latter. Also ricinoleic acid, which is an unsaturated form of 12-hydroxystearic acid and in the 9-10 position has a double bond can be used. Other usable hydroxy fatty acids

acids are 12-hydroxy behenic acid and 10-hydroxypalmitic acid.

If a second hydrocarboxylic acid is used together with the boric acid and the hydroxy fatty acid, is it one in which an OH group is attached to a carbon atom that is no more than 6 carbon atoms away from the carboxyl group This acid has 3 to 14 carbon atoms in the molecule and can either be an aliphatic acid, such as lactic acid, 6-hydroxy decanolic acid, 3-hydroxybutanolic acid, 1-hydroxycaproic acid, 4-hydroxybutanolic acid, 6-hydroxyalpha-hydroxystearic acid and the like, or one aromatic acid such as parahydroxybenzoic acid, salicylic acid, 2-hydroxy-4-hexyibenzoic acid, metahydroxybenzoic acid, 2 ^ -dihydroxybenzoic acid (gentisic acid), 2,6-dihydroxybenzoic acid (gamma-resorcic acid), 4-hydroxy-4-methoxybenzoic acid and the like , aliphatic acid, such as orthohydroxyphenyl-, mctshydroxyphenyl- or Parahydroxyphenylic acid. A cycloaliphatic hydroxy acid such as hydroxycyclopentylcarboxylic acid or hydroxynaphthalic acid can also be used. Particularly suitable hydroxy acids are Lactic acid, salicylic acid and parahydroxybenzoic acid.

It can also be used instead of a free hydroxy acid of the last-mentioned type in the production of the fat Lower alcohol esters, for example methyl, ethyl, propyl, isopropyl or secondary butyl esters of the acid, such as methyl salicylate, to achieve better dispersion when the salt is insoluble. The amount of The lithium salt of the hydroxy acid ranges between about 0.1 to about 10% by weight of the finished product Fat and preferably between about 0.2 to about 5% by weight. Either the monolithium salt or the dilithium salt of the second hydroxysäjε can be used however, the dilithium salt is preferred.

The total soap and salt content of the fat ranges from about 2 to 30% by weight, and preferably from about 5 to 20% by weight. The ratio of Hydroxy fatty acid with 12 to 24 carbon atoms in the molecule to boric acid is in a range of Weight ratio of about 3 to 100 parts or more, usually about 5 to 80 parts of the Hydroxy fatty acid per part by weight of boric acid. The result is a weight ratio of about 0.1 to 10 or more, usually about 0.5 to about 5 parts of said second hydroxycarboxylic acid per part by weight Boric acid, in the event that the fats are made from three acid components.

The lubricating oil base used in the preparation of the fat compositions according to the invention can be any conventional mineral oil synthetic hydrocarbon oil or synthetic ester oil, and generally has a Viscosity in the range of about 35 to 200 SUS at 99 ° C. Useful lubricating oils include esters of dibasic acids, such as di-2-ethylhexyl sebacate, Esters of glycol, such as a diester of an oxo acid having 13 carbon atoms of tetraethylene glycol, or Complex esters, such as those obtained by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol or 2 moles 2-ethylhexanol acid were formed. As other Synthetic oils can include synthetic hydrocarbons such as alkylbenzenes, for example the alkylated ones Residues from the alkylation of benzene with tetrapropylene. or copolymers of ethylene and Propylene can be used, as well as silicone oils, such as

z. B, Äthylphenylpclysiloxane, Methylpolysiloxane and the like, and also polyglycol oils, such as those obtained by the condensation of butyl alcohol with propylene oxide are obtained, also carbonate esters, such as. B. that Product of the reaction of an oxo alcohol containing 8 carbon atoms with ethyl carbonate to form half a shoulder, followed by the reaction of the latter with tetraethylene glycol, and the like. Other suitable synthetic oils are polyphe-

nylon ether, such as B. those that have 3 to 7 ether bonds ui d have about 4 to 8 phenyl groups (see also American patent specification 34 24 678, column 3).

The fats can be made by neutralizing all three types of acids together or else, by first adding the boric acid and the hydroxy fatty acid are neutralized together, whereupon subsequently the lithium salt of the second hydroxycarboxylic acid is formed.

The following examples, the preferred execution

Represent approximately forms, explain the production and the various properties of the invention manufactured fats. Comparative examples are also given, which show that poorer results are obtained obtained if the boric acid is omitted or if the boric acid is neutralized via the monolithium salt stage.

example 1 (including comparison fats)

The fat labeled A was made by

a combination of lithium 12-hydroxystearate and monolithium borate is used as a thickening agent became. The base oil used in the production of this grease was a solvent refined »Mid-Continent lubricating oil distillate«, which was sold under the designation "Solvent 450 Neutral" is known. and has a viscosity at 38 ° C of about 450 SUS. the 12-hydroxystearic acid was partially added to the base oil (about half of the total oil, what ii) the finished fat is used), whereupon the Mixture was heated until the 12-hydroxystearic acid melted, this temperature being approximately 82 ⁰ C to 88 ° C. The boric acid and lithium hydroxide monohydrate were then added as an aqueous solution, followed by the resulting mixture

so stirred and up to a final temperature of about 193 ° C until! 99 "C. The remaining part of the (: Rundöls was then added and the mixture was cooled to ambient temperature and placed in a conventional mill. In addition, de produced a comparison fat that corresponds to fat A , but omitting the boric acid.

Two additional fats were made, each having the same ratio of 12-hydroxystearic acid and boric acid to base oil as in Case A , but while increasing the amount of lithium hydroxide monohydrate to form a dilithium borate and trilithium borate in place of the monolithium borate.

Each of the fats made in this way was

tested for its drop point and its ASTM penetration at 25 ° C. The composition of the Fats and their test sample results are compiled in Table I below.

22 35 098 Comparative Feti 7.0 6th 17.2 Trilithium 23.8 5
Ta! " C '-' t I No 50 50 borate 50 Composition, grams According to the invention Boric acid 0 Dilithium 8.3 3 8.3 Monolith overbombed i 433.1 borai 433.1 433.1 2 . * · 208 215 206 LiOH · H ₂ O 12.6 239 218 220 12-hydroxystearic acid 50 Boric acid 8.3 Gmndöi 433.1 Test results Drop point, ⁰ C 251 ASTM penetration at 25 ° C 231 after 60 stresses

The values in Table I show the following:
A comparison of fat A with fat 1 shows that the monolithium borate results in a high dropping point fat of a desirable consistency. The values for fats 2 and 3 show that when the ratio of lithium to boric acid is above that for the formation of monolithium borate required ratio increase? the desired drop point improvement is not achieved.

Example 2

There were prepared two fats, using as thickener a combination of Dilithiumsalicylat, lithium hydroxystearate 12 and monolithium borate has been used, the ratios of the Ve ^r dikkungsmittelbestandteile were changed in the two fats. The base oil used to make these fats was a solvent refined "mid-continent lubricating oil distillate" known as "Solvent 600 Neutral" which has a viscosity at 38 ° C of about 600 SUS methyl salicylate and 12-hydroxystearic acid added to part of the ground, whereupon the mixture was heated. After the 12-hydroxystearic acid was observed to have melted, the temperature being about 82 ° C to 88 ° C, all of the lithium hydroxide used to form the various lithium salts became 10% strength

Table II

added to the aqueous solution, and the boric acid required for the production of the fat had also been added to this solution. The resulting mixture was stirred and y> .s eriiir.it to a temperature of about 193 ° C to 199 ⁼ C. Then the remaining portion of the base oil was added and the mixture was cooled to about 121 ° C, whereupon an antioxidant and other fat ingredients such as e ^; <5 agents to prevent rust formation were added. The fat was then ground in a conventional fat mill.

Comparative example

Comparative greases were prepared using the same method as in Example 2, with in In one case the methyl salicylate and in the second case the boric acid were omitted, while in the third case neither boric acid nor methyl salicylate were used. In each case the appropriate amount was used Lithium hydroxide, which was required to form the soap or the salt of the omitted ingredient, also omitted.

Each of the fats prepared in Example 2 and Experimental Example were tested for their dropping point and its ASTM penetration at 25 ° C. The composition of these fats and their test results are compiled in the following table II.

Composition in% by weight Fat according to the
invention N Comparative fats Y Z M. 1.9
10.4
0.5
0.5
84.7
1.0
1.0 K 2.9
11.5
2.5
81.1
1.0
1.0 1.8
12.9
85.3 LiOH · H ₂ O
J? .- hydroxystearic acid
Boric acid
Methyl salicylate
Base oil
Phenyl-alpha-naphthylpmin
Na-SuI-BSN 4.0
12.9
1.1
2.7
78.3
1.0 2.5
12.9
1.1
82.5
1.0 Test results üujr 260 213 2t 7 T top point, ° C over 260 275 225 217 ? 61 ASTM penetration at 25 ° C
unprocessed 252 280 2 '2 240 250 after 60 stresses 261 2V9 255 243 277 after 10,000 loads 293 291

The phenyl-alpha-naphthylamine mentioned in the table was used as an antioxidant. The term Na-SuI-BSN is a brand name for a Product that acts as a rust preventive. It is a 50 wt .-% concentrate of a neutral barium salt of the dinonylnapthalenesulfonic acid derived from tripropyien-alkylated naphthalene in a light mineral oil.

When looking at the values in Table II, a comparison of the fat X with the fats Z and M shows that if monolithium borate is added to the lithium hydroxystearate fat, the dropping point increases somewhat, although there is a considerably greater increase in the

Drip point results, if in addition, lithium salicylate is used. A comparison of the fats VZ shows that with an addition of lithium salicylate without monolithium borate the dropping point is not improved significantly.

Various other conventional additives can be included in the composition of the invention as those skilled in the art know. Such additives are, for example, antioxidants, agents for preventing

in the prevention of rust formation. Means to improve the Adhesion, skin-modifying agents. Colours. High-viscosity agents and the like.

Claims (1)

1 claims: 1. Lubricating grease, for the most part from a lubricating oil and from 2 to 30 percent by weight, calculated on the total mass, consisting of a thickening system that