DE1037049B - High pressure grease - Google Patents

Description

GERMAN

kl. 23 c 1/04

INTERNAT. KL. C 10IH

PATENT OFFICE

N12173IVc / 23c

REGISTRATION DATE: APRIL 26, 1956

NOTIFICATION OF REGISTRATION
AND ISSUE OF THE
EXPLORATION GIFT: 21st AU GU ST 19 5 8

The invention relates to high pressure greases that are thickened with inorganic gelling agents and can therefore be used at relatively high temperatures.

Lubricating greases suitable for use e.g. B. in wheel bearings, roller bearings, spindles, chassis and general Articulated joints are intended to have good lubricating properties even under severe conditions as they often occur in steel rolling mills and the like. In addition, the In many cases, lubricating greases have a high resistance to water leaching or possess moisture.

It is true that inorganically gelled greases with good resistance to one already have Leaching by water and also produced with desirable mechanical properties, but suitable they are not used even when most of the known extreme pressure additives are used under particularly high loads.

It has already been recommended to use metal-free aliphatic oxy or mercapto compounds with at least To use 8 carbon atoms in the molecule as a means to improve water resistance or for the same purpose very high molecular weight and water-insoluble esters of oxyfatty acids and polyvalent ones To use alcohols.

In order to influence the water resistance, consistency and the corrosion properties of such lubricating greases favorably, an addition of water-soluble organic compounds with not more than 6 carbon atoms in the molecule and an electrical dipole moment between 1.2 and 2.8 · 10 ~ ^{18 has been} described, for example of lactic acid, the amount of the additive being up to 60% based on the weight of the gelling agent.

It has now been found that inorganically gelled lubricating greases then have particularly favorable extreme pressure properties have if the lubricating oil base is a mineral lubricating oil, which is at least Contains 1 percent by weight of such components when reacted with a saturated aqueous Mercury chloride solution forms solid complexes at 20 ° C for 10 minutes, and if these greases as a high-pressure additive, at least 2.5 percent by weight of a water-soluble aliphatic oxycarboxylic acid as such or in the form of their heat condensation product with an aliphatic polyhydric alcohol contain.

The term "water-soluble" used in relation to the aliphatic oxycarboxylic acids means that the the acid in question has a solubility of at least 0.5 percent by weight in water at 20 ° C. Pre-high pressure grease

Applicant:

N.V. de Bataafsche Petroleum Maatschappij, The Hague

Representative: Dr. K. Schwarzhans, patent attorney, Munich 19, Romanplatz 9

Claimed priority: V. St. v. America April 28, 1955

Walter Howard Peterson, Emeryville, Calif. (V. St. Α.), Has been named as the inventor

preferably the solubility should be at least 2%.

Examples of suitable acids can be mentioned:

Monooxycarboxylic acids, such as glycolic acid, lactic acid, 1-ethylidene lactic acid, 2-ethylidene lactic acid, Ethylene lactic acid, oxycaproic acid, a-oxybutyric acid, Acetonic acid, leucic acid, a-oxycrotonic acid, α-oxyvaleric acid;

Polyoxycarboxylic acids, such as glyceric acid, arabonic acid, Gluconic acid, galactonic acid, talonic acid, mannonic acid;

Oxypolycarboxylic acids, such as citric acid, tartaric acid, trioxyglutaric acid, saccharic acid, tartronic acid, Malic acid.

It has been found that a minimum of 2.5% of the carboxylic acid or its heat condensation product, calculated on the weight of the total grease, must be applied. In general, additives of more than about 20 percent by weight are calculated on the total grease, not recommended. The maximum improvement will be achieved in most cases at a concentration on the order of about 8 to 12%. The used Amount of carboxylic acid depends largely on the severity of the conditions, which the grease is subjected, as well as of the acid used in the individual case.

The aliphatic polyhydric alcohols used to make heat condensation products are preferably lower, polyhydric aliphatic alcohols, such as the lower ones Alkylene glycols having 2 to 6 carbon atoms per

«09 598/514

Molecule, "ζ. B. Ethylene, diethylene, triethylene, Propylene, DipropyleH or butylene glycol. But hydrocarbons such as sugar can also be used and their derivatives. The pentoses and hexoses, including ribose, arabinose, giu cheese, Fructose, galactose and mannose, as well as hexites, e.g. B. sorbitol or mannitol are preferred. The mixtures of the oxyacids and the alcohols to be heated should preferably be a predominant one Containing proportion of acids, and mixtures are particularly expedient treated, which 75 to 90 percent by weight (calculated on the mixture) of the acids.

Heat condensation products are understood to mean products that are produced by heating the acid-alcohol mixture can be obtained at a temperature between about 100 and 200 ° C. for about ½ hour to about 4 hours. It has been shown that under these conditions a number of complicated and confusing reactions occur, the main ones being in a polycondensation of the acids and in a simultaneous esterification of the acids or whose polycondensation products exist. The course of condensation can be determined by measuring the during the amount of water developed during the condensation process can be tracked. It is preferred to work in such a way that that the proportion of water formed during the process is between 5 and 12 percent by weight and in particular between 6.5 and 9.5 percent by weight of the original mixture. A preferred mode of operation is to remove this water as it is formed; man but can also leave limited amounts in the product.

The lubricating oil components in the high-pressure lubricating greases according to the invention are in particular the so-called "red oils" or "black oils" in question.

The components contained in such oils, which will react with saturated aqueous mercuric chloride solution under the specified conditions commonly referred to as "asphaltogens," but their exact chemical composition is for the discussion of the present invention is immaterial. The suitability of a special oil as part of the Invention can easily be determined with the described mercuric chloride complex formation. Even though any oil containing at least 1% by weight of the mercury chloride complex forming material, Can be used, but oils that are at least 5 and preferably at least 15 percent by weight of such substances, preferred, wherein the upper limit is not specified, but usually on the order of 50% by weight lies. Lubricating greases made using such oils are not only much cheaper manufacture as such from refined oils, rather they also have sufficient water resistance for many purposes. Red oils and those for the invention Black oils particularly suitable for lubricating greases have a viscosity between about 100 and about 1200 SUS at 37.8 ° C.

The inorganic gelling agent in the lubricating greases according to the invention can e.g. B. be a clay or an amorphous colloid. Bentonites are suitable clays. Suitable amorphous colloids are those with a large surface area, e.g. B. at least about 100 m ² per gram. Such colloids can be obtained by the so-called airgel, which is described in the USA. Patent no. 2,260,625. Silica, magnesia, alumina and mixed colloids such as silica-calcium oxide or silicon dioxide-magnesia are examples of this group.

The amount of gelling agent used must be sufficient to achieve a real grease structure to ensure. Usually this amount is between 1 and 10 percent by weight of the Total mixture and preferably between 1.5 and 5 percent by weight.

Ui-i the compatibility between the oil base and the inorganic gelling agent as well as the You can improve the water resistance of inorganically gelled greases by themselves incorporate known surfactants. Cationic surfactants are generally used preferred. Suitable additives of this type are those aliphatic amines which at least contain an alkyl group with 10 or more carbon atoms, as well as the corresponding ammonium salts, for example decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, octadecylammonium acetate, Dimethyldioctylammonium acetate, dimethyldidodecylammonium acetate, dimethylhexadecyloctadecylammonium acetate and the corresponding chlorides.

Other suitable cationic surfactants are disclosed in U.S. Patents 2,625,222 and 2,623,852.

The surfactant additives are either from the surface of the inorganic gelling agent adsorbed, or they react with the same. In clays, which have exchangeable alkali atoms contain, like the bentonites, and with amine salts generally an ion exchange reaction occurs, which leads to the formation of so-called "onium tones". In the case of amorphous colloids, adsorption usually occurs.

The surfactants are generally in an amount between 30 and 100 percent by weight, preferably between 70 and 95 percent by weight calculated on the inorganic gelling agent, contained in the grease.

Another measure to improve the water resistance of lubricating greases, in particular if these contain a silicon dioxide-containing gelling agent, there is a superficial reaction the gelling agent with an alcohol to form an ester. The so-called "Estersiis" are described in more detail in US Pat. No. 2,676,148.

In preparing the lubricating greases of the invention, a preferred mode of operation is that the gelling agent is dispersed in water to form a hydrogel or hydrosol, which then mixed with the lubricating oil. The mixture is then subjected to a stirring or shearing action subjected, whereby a transfer of the gel from the aqueous phase brought about in the oil will. A substantial part of the water separates itself from the main mass of the lubricating grease components and can be removed by settling or decanting, whereupon the remaining water z. B. removed by distillation. The remaining grease components then become a strong one subjected to shearing action to achieve the grease structure. The oxycarboxylic acid or Their heat condensation product can be added to the grease after the water phase has been separated off separates from the grease components, incorporated

I 037

will; but it can also pass through during the final separation of the remaining water content Distillation be present. On the other hand, it can also be incorporated into the dehydrated grease will.

Mixtures of the oxycarboxylic acids or their heat condensation products can also be used Mixtures of the same with other extreme pressure additives and with other additives known per se, such as antioxidants, can be used. The arylamines are particularly suitable for the purposes of the invention To stabilize lubricating greases against oxidation, especially the phenylamines and the Phenylnaphthylamines, such as phenyl-a-naphthylamine and phenyl - /? - naphthylamine. Furthermore, the Adding a small amount of a strong acid to a mixture of clay and organic base as Proven to improve the hydrophobic properties of lubricating greases. It can lead to this Purpose hydrochloric acid, sulfuric acid and phosphoric acid can be used, the latter being preferred will. The amount of acid is preferably between about 85 and 110% of that amount sufficient to acidify the base-exchanging parts of the clay.

For the purpose of comparison, high-pressure greases were produced according to the following procedure: Hectoritton freed from gait. was dispersed in water and mixed with the atninoamide, which is made from tall oil acids and a condensation product of epichlorohydrin with ammonia had been formed, treated. For every 37 parts by weight of clay, the dispersion was still 2.6 parts by weight incorporated into an 85% phosphoric acid. When the condensation product was added, it differed a substantial amount of water will separate from the clay hydrogel. The water was removed and the remaining components were black residue lubricating oil with the following properties added:

Viscosity Ill SSU at 98.9 ⁰ C

Molecular weight (average) 416

Specific gravity / 15 ⁰ . 0.953

Sulfated ash 0.055%

Ramsbottom carbon

backlog 7.3%

The dehydrated grease contained 3.7 weight percent clay, 3.2 weight percent condensation product modified by the presence of Phosphoric acid; the remainder of the mixture consisted of black oil.

This grease blend was further modified by adding varying amounts of the test Considered extreme pressure additive.

55

Additive Timken test:
pressure
at the time
of failure
kg / cm ² No 1.05
1.96
2.66
2.31
3.01
3.50
3.36 4% sulphurized bacon oil
10% chlorinated naphthalene ....
8% boric acid
8% tartaric acid
8% lactic acid
10% (of a complex of 85%
Tartaric acid and 15% pro
pylene glycol)

60

65

70 It is apparent from these results that greases the invention provide completely unexpected advantages in terms of high-pressure properties. Combinations of lard oil and lead naphthenate are z. B. used in numerous common, with soaps thickened lubricating greases and work quite satisfactorily in these. However, as the above figures show, these substances are only moderately effective in clay lubricating greases with the special oil base claimed.

The comparative tests were carried out under the following conditions: A Timken cup is rotated in a device known as a Timken testing device relative to a loaded Timken block. For testing grease, this machine is equipped with a special feed cylinder to feed the grease to the cup. The load capacity of a lubricating grease is measured at room temperature and 800 revolutions per minute by increasing the load on the block until metal particles tear or seize. The maximum load (kg / cm ² on the lever arm loading the block) at which the device works for 10 minutes without scuffing is referred to as the OK value or load capacity "of the lubricant (cf. Inst, of Petr., April 16, p 106 and J. Soc. Automotive Engineers, 28, 53, 1931).

Another example of a grease according to the invention is the following:

Tartaric acid, finely divided
Shape, made like
described below 2.5 percent by weight

Sodium stearate 0.1 ,,

Colloidal bentonite 4.0

Semi-refined mineral
Lubricating oil ("red oil") .. 92.4

The water-soluble oxycarboxylic acids or their heat condensation products are the new ones Lubricating greases are conveniently incorporated using the following procedure: The water soluble Material is dissolved in water and the resulting solution with the lubricating oil in the presence of a Emulsifier, which is able to form water-in-oil emulsions from the two phases, emulsifies. Suitable emulsifiers are e.g. B. the alkali salts, especially the sodium soaps, of fatty acids with at least 12 carbon atoms in the molecule. Following a typical example, it is convenient to use tartaric acid to dissolve in water to a 10% aqueous solution, which is then with an equal proportion of the mineral lubricating oil is emulsified, which is about 0.5 to about 5%, calculated on the tartaric acid Contains sodium stearate. This mixture is then dehydrated by heating, and the resulting finely divided tartaric acid particles are suspended in the remaining lubricating oil. It was determined, that they have an average particle size of less than about 2 microns.

The manufacturing processes described above for the new lubricating greases are to be used in the context of present invention are not protected. The same applies to the use of Red oils or black oils as a lubricating grease component. The on this basis according to patents 1 001 795 and 1 001 796 built-up greases differ from the greases according to the present invention.

Claims (7)

PATENT APPROACH: 1. High-pressure lubricating grease based on mineral oil, which contains an inorganic colloid as a thickener and a water-soluble, aliphatic oxycarboxylic acid in an amount of at least 2.5 percent by weight, calculated on the total mixture, as an additive, characterized in that the oil component is a mineral lubricating oil which is at least 1 Has percent by weight of those components which form solid complexes on reaction with a saturated aqueous mercuric chloride solution at 20 ° C for 10 minutes, and that in addition the oxycarboxylic acid as such or in the form of an aliphatic polyvalent acid by heating it ^{for 1 to 4 hours} Alcohol to 100 to 200 ° C obtained heat condensation product is present therein. 2. High pressure grease according to claim 1, characterized in that it is the oxy acid or their heat condensation product in an amount of 2.5 to 20 percent by weight, and in particular in an amount of 8 to 12 percent by weight, calculated on the total mixture. 3. High pressure grease according to claim 1 and 2, characterized in that it is a heat condensation product contains, in which the reaction has preferably been continued until 5 to 12 percent by weight of water, based on the reaction mixture have formed. 4. High pressure grease according to claim 1 to 3, characterized in that it is a heat condensation product from a predominant proportion of the oxycarboxylic acid, preferably 75 to 90 percent by weight, and a smaller proportion of the aliphatic alcohol, preferably 25 to 10 percent by weight, contains. 5. high pressure grease according to claim 1 to 4, characterized in that the heat condensation product as the alcohol component a lower, aliphatic, polyhydric alcohol such as contains an alkylene glycol, in particular propylene glycol. 6. high pressure grease according to claim 1 to 5, characterized in that it is the inorganic Gelling agent in an amount of 1 to 10 percent by weight, calculated on the total mixture, contains. 7. high pressure grease according to claim 1 to 6, characterized in that there is also a minor amount, preferably 30 to 100 percent by weight, calculated on the inorganic Gelling agent, a surfactant known per se. Considered publications:
British Patent Nos. 719 982, 685 146. Legacy Patents Considered:
German patents 944 627, 1 001 795, 1 001 796. ι 809 598/514 8.58