DE1001796B - High pressure grease - Google Patents

Description

The invention relates to thickened with the composition of inorganic gelling agents High pressure greases.

Lubricating greases have been made by dispersing soaps or inorganic gelling agents in lubricating oils. Lubricating greases thickened with inorganic gelling agents have the Advantage that they can be used at relatively high temperatures.

Lubricating greases, which are suitable for general use in the field of mechanical engineering (e.g. for wheel bearings, roller bearings, etc., spindles, chassis and general articulated connections, etc.) should, in addition to good lubricating properties for use under difficult conditions z. B. as rolling mill grease, also have high pressure properties. Also, the greases must in many cases high resistance to water or moisture leaching own.

It is already known the composition of lubricating greases with inorganic gels, which one good resistance to water leaching as well as the desired mechanical properties to have. However, the good lubricating effect under exceptionally high loads is due to the application most of the known extreme pressure additives commonly found in lubricating oils and in greases gelled by soaps have not been achieved in a satisfactory manner.

It has now been found that alkali and ammonium hydrogen phosphates, in amounts of at least 2.5 percent by weight, calculated on the grease, of the greases containing inorganic gels give surprisingly favorable high pressure properties. The remarkable effect of the alkali and ammonium hydrogen phosphate compared to other known extreme pressure additives supported by figures below.

As examples of alkali and ammonium hydrogen phosphates which can be used in the lubricating greases according to the invention are called:

Sodium hydrogen orthophosphate, Na ₂ HPO ₄ · 12 H ₂ O sodium dihydrogen orthophosphate, Na H ₂ PO ₄ · H ₂ O sodium hydrogen hypophosphate, Na HPO ₃ · 3 H ₂ O sodium hydrogen pyrophosphate, Na ₂ H ₂ P ₂ O ₇ · 6 H ₂ O potassium monohydrogen orthophosphate, K ₂ HPO ₄
Potassium dihydrogen orthophosphate, KH ₂ PO ₄
Ammonium monohydrogen orthophosphate,

(NH ^ ₂ HPO ₄ '

Ammonium dihydrogen orthophosphate, NH ₄ H ₂ PO ₄
Ammonium hypophosphate, (NH ₄ ) ₂ H ₂ P ₂ O ₆
Sodium ammonium hydrogen orthophosphate,

NaNH ₄ HPO ₄

Applicant:

NV De Bataafsche Petroleum
Maats chappij, The Hague

Representative: Dr. K. Schwarzhans, patent attorney,
Munich 38, Romanplatz 9

Claimed priority:
V. St. v. America March 21, 1955

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

A feature of the present invention is the finding that the proportion of acid phosphate (Hydrogen phosphate) must be relatively high if satisfactory extreme pressure properties are achieved should be. This contradicts the common lubricating oils in the absence of gelling agents results obtained at which fractions of a percent of an extreme pressure additive usually sufficient to improve the high pressure properties in a suitable manner. It is established that the grease has a minimum amount of 2.5% of the hydrogen phosphate, calculated on the Weight of the total mixture. Usually has the addition of more than about 12 percent by weight, calculated on the total mixture, no further effect, as the greatest improvement in most cases at a concentration below this value and of the order of about 8 to 10% is obtained. The preferred range is between about 3.5 and 8 weight percent calculated on all grease.

The amount of acid phosphate used depends to a large extent on the operating conditions, in which the lubricating grease is used, as well as the phosphate used in individual cases. If the mixture is e.g. B. prolonged use under high pressure conditions such as rolling mills is subjected, the amount of acid phosphate required is much greater than when working under relatively milder conditions.

The lubricating oil base in the lubricating greases according to the present invention can be any of the conventional lubricating oil

609 768 / 2T1

grades that are usually used in the production of lubricating grease can be used, e.g. B. a refined, unrefined or semi-refined, paraffinic, naphthenic or asphalt-based "mineral oil with a viscosity of about 50 to 4000 Saybolt seconds (universal) at 37.8 °. If desired, a mixed lubricating oil of suitable viscosity can be substituted a single lubricating oil can be used, creating a desired viscosity within that specified

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

Another known measure to improve the resistance of the grease to Water, which is particularly useful when a silica containing gelling agent is used is, consists in the formation of an ester with

surface) are described in U.S. Patent 2,676,148.

It is understandable that it would be desirable

Area can be obtained. The viscosity of the gelling agent. This esteriis (powder with lubricating oil has only a minor influence on the drop-esterified silanol groups [—SiOH] at the upper point of the mixture; however, the more viscous lubricating oils result in products with better adhesion properties than the lighter lubricating oils. The special
Lubricating oil, as well as the exact amount used in improving the water resistance of the lubricating oil component, will depend on the properties desired in the finished lubricating grease using expensive chemical grease.

The inorganic gelling agent in the mixture according to the invention can, for. B. a sound or a be amorphous colloid. Suitable clays are bentonites.

to avoid calories and cumbersome procedural measures.

An important feature of the present invention of the 20 is that in many cases it refers to the aforementioned Measures can be dispensed with if one

The inorganic gelling agent and an alkali or amorphous colloid which can be used in the context of the invention are those having a large surface area of ammonium hydrogen phosphate in a lubricating oil, e.g. B. at least about 100 m ² per pergated, provided that the oil is not refined or grams, such as the colloids, which according to the airgel 25 is a semi-refined lubricating oil in the sense described below in US Pat. No. 2,260,625 . It is believed that this

is attributable to the presence of polar substances in these oils. It should be noted that appropriate a surfactant is used,

is obtained, e.g. B. silica, magnesia, alumina and mixed Colloids, such as silica lime or silicon

dioxide-magnesium oxide. 30 if very high water resistance is

The amount of that contained in the grease is desired.

Gelling agent has no decisive importance The special mineral lubricating oils are those

which contain at least 1 percent by weight of constituents with a saturated aqueous mercury

within the meaning of the present invention. The gelling agent should, however, be present in sufficient quantities

in order to give the mixture a grease structure, forming a chloride solution at 20 ° in 10 minutes

Rent. Usually the amount is between 1 and 10 percent by weight, calculated on the total mixture, and preferably between 1.5 and 5 percent by weight.

solid complexes which can be separated off by filtration react. The so-called red oils or black oils Lubricating oils meet this requirement.

Those with saturated aqueous mercury chloride under

Various measures are known for substances that react under the specified conditions Improving the compatibility between the oil are usually referred to as asphaltogenic substances,

but their precise chemical identification is not essential to a discussion of the present invention necessary. The suitability of a lubricating oil

and the inorganic gelling agent and to improve the water resistance of the inorganic Lubricating greases. One of these measures exists

in the incorporation of a surfactant 45 to induce good compatibility with into the grease. The surface active agent can be inorganic gelling agents can be easily and one-anionic, be cationic or non-ionic. Katif with the help of the Mercuricomplexonic described Surfactants will generally be determined by education. Though for the present preferred. Examples are the aliphatic invention any lubricating oil is useful, the minde-amines, which at least one alkyl group with ten 50 at least 1 percent by weight of one mercury chloride or contain more carbon atoms, as well as the ent- complex-forming material, will be speaking ammonium salts. Examples of such amines preferably lubricating oils with at least 5% and or their salts are: decylamine, dodecylamine, special those with at least 15 percent by weight Tetradecylamine, hexadecylamine, octadecylamine, Oc- such substances are used, whereby the upper limit is not tadecylammonium acetate, dimethyldioctylammonium 55 is precisely defined, but in general size acetate, Dimethyldidodecylammonium acetate, dimethyl is properly 50 percent by weight. Under

Lubricating greases made using such lubricating oils are not only significantly cheaper to manufacture than when using refined lubricating oils, but also have sufficient water resistance for many purposes. Red oils and the black oils, which are particularly useful for the present mixtures, have viscosities between about 100 and about 1200 Saybolt seconds (universal) at 37.8 °.

In the preparation of the mixtures according to the

as well as the

hexadecyloctadecylammonium acetate-speaking chlorides.

Other examples of suitable cationic surfactants are found in U.S. Patent 2,625,222 described. A particularly preferred group of cationic surfactants is disclosed in the U.S. patent 2 623 852. The substances described there are polyaminohydroxy compounds, in which the total number of amine nitrogen atoms and oxy groups is at least three, where preferably 30 to 70% of the amino groups by reaction with carboxylic acids with ten or more carbon atoms, like the higher fatty acids, are converted into amide groups.

of the invention is preferably the gelling agent in water to form a hydrogel or a Hydrosols dispersed and then mixed with the lubricating oil, the acidic phosphate together with, before or after adding the gelling agent

can be given. The mixture of lubricating oil and hydrosol is then subjected to a stirring or shearing treatment, a substantial proportion of the water separates from the bulk of the Grease components from and can be separated by settling or decanting, whereupon the remaining water z. B. can be removed by distillation. The remaining grease components a harsh, shearing clay-containing grease mixture will only be moderately effective. Even closely related compounds, such as trisodium phosphate, gave unsatisfactory results.

The test used for these comparative experiments is carried out under the following conditions: Man has a Timken cup against a loaded Timken block in what is known as a Timken testing machine Rotate arrangement. This machine is equipped with for testing lubricating greases

Action for the purpose of generating the lubricating grease structure in a special feed cylinder for the addition subject. For the production of lubricating grease, guiding the grease into the cup. The load itself however, no protection is claimed.

For comparison between the acid phosphates and other types of useful extreme pressure additives greases were made as follows: hectorite clay, which had been stripped of gangue, was dispersed in water and treated with the amino amide, which is derived from tall oil acids and a condensation product of epichlorohydrin with ammonia has the bearing capacity (coefficient of friction) of a lubricating grease is measured at room temperature at 800 revolutions per minute by increasing the load on the Block until seizure or cracking occurs. The maximum load (English, pound load on the lever arm, which loads the block), in which the treatment lasts 10 minutes without eating or Scoring occurs is called an OK load or load

was educated. For every 37 parts by weight of the clay, 20 load-bearing capacities of the lubricant were designated. It 26 Gihil 85 ° / i Phha

2.6 parts by weight of 85% phosphoric acid added to improve the dispersion. An essential one Part of the water separated from the clay hydrogel when the condensation product was added. That Water was removed and the remaining ingredients were added to a black residual lubricating oil having the following properties exhibited:

Viscosity 111 Saybolt seconds

(universal) at 98.9 ° molecular weight (average) 416.0

API density 17.0

Sulfated ash 0.055%

Ramsbottom carbon

backlog 7.3%

35

The dehydrated grease contained 3.7 percent by weight clay and 3.2 percent by weight of the condensation product (modified by the presence of phosphoric acid) while the rest of the mixture is made up Black oil existed.

This grease was further modified by adding varying amounts of each to be tested Extreme pressure additive.

Timken test; Load at time of failure (kg / cm ² )

1.05

Additives
no

4 percent by weight of lard oil + 2 percent by weight lead naphthenate. . 1.96 10 weight percent chlorinated

Naphthalene 2.66

8 percent by weight boric acid 2.31

8 percent by weight sodium metasilicate 1.19

8 percent by weight trisodium phosphate 0.70

8 percent by weight sodium dihydrogen phosphate monohydrate over 7.00

From these results it can be seen that the use of sodium dihydrogen phosphate in relation to on the extreme pressure properties of the grease gives a quite unexpected benefit. Combinations of lard oil and lead naphthenate are z. B. in numerous commercially available, gelled with soaps Lubricating greases are used and are quite satisfactory in such lubricating greases. But like the ones given above Numbers indicate were these additions are in the reference Inst, of Pet., April 16, p. 106, and J. Soc. Automotive Engineers, 28, 53, 1931.

Further examples of lubricating greases according to the invention are:

A. Silica aerogel 5 weight

percent

Bis (2-ethylhexyl) sebacate 91

K ₂ HPO ₄ 4

B. Oniumton, formed from Wyoming-

bentonite and dimethylcetylammonium chlorides 8

semi refined mineral

Lubricating oil ("red oil") 86

NH ₄ H ₂ PO ₄ 6

C. Wyoming Bentonite 4

Condensation product of epichlorohydrin and ammonia; one third of the amino groups converted with oleic acid in amide groups 3

Medium viscosity mineral lubricating oil 83

Disodium pyrophosphate 10

It is clear that mixtures of the acidic phosphates are used and that mixtures of the same with others known extreme pressure additives or with other additives such as antioxidants can be. In the latter regard, arylamines have proven themselves in terms of stabilizing ability of the present lubricating greases have proven to be exceptionally beneficial against oxidation. Suitable Arylamines include in particular the phenylamines and especially the phenylnaphthylamines, such as phenyl-a-naphthylamine and phenyl - /? - naphthylamine. The incorporation of a small amount of a strong acid into a combination of clay and Organic base has been used to improve the hydrophobic properties of lubricating greases proven favorable. Hydrochloric acid,

Sulfuric acid and phosphoric acid can be used, the latter acid being preferred. Of the The proportion of acid is expediently between about 85 and 100% of the amount required to acidify the Base exchange units of the clay is required.

Claims (10)

PATENT CLAIMS: 1. High-pressure lubricating grease based on a preferably mineral lubricating oil and one inorganic gelling agent by a content of at least 2.5 percent by weight, calculated on the total mixture of an acidic alkali or ammonium phosphate. 2. High-pressure grease according to claim 1, characterized in that the acidic alkali or Ammonium phosphate in an amount of 2.5 to 12 percent by weight, calculated on the total mixture, is present. 3. high-pressure lubricating grease according to claim 1 or 2, characterized in that the acidic Alkalibzw. Ammonium phosphate in an amount of 3.5 to 8 percent by weight, calculated on the total mixture, is present. 4. high pressure grease according to claim 1 to 3, characterized in that the acidic phosphate Alkali dihydrogen phosphate or sodium dihydrogen phosphate monohydrate. 5. high pressure grease according to claim 1 to 4, characterized in that the inorganic gelling agent a tone, e.g. B. bentonite or hectorite or an amorphous colloid, e.g. B. is silica. 6. high pressure grease according to claim 1 to 5, characterized in that the inorganic Gelling agent in an amount of 1 to 10 percent by weight, calculated on the total mixture, is present. 7. high pressure grease according to claim 1 to 6, characterized in that the lubricating oil base is a mineral lubricating oil which has a content of at least 1 percent by weight of such Contains components that when reacted with a saturated aqueous mercuric chloride solution at 20 ° ίο Form solid complexes for 10 minutes. 8. high-pressure grease according to claim 1 to 7, characterized in that there is also one contains a small amount of a known surfactant. 9. high-pressure grease according to claim 8, characterized in that it is used as a surface-active Agent contains a cationic surfactant. 10. High-pressure grease according to claim 8 or 9, characterized in that it is the surface-active Agent in an amount of 30 to 100 percent by weight, calculated on the inorganic Gelling agent.