DE1170099B - Organopolysiloxane-based lubricating grease - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Kl .: ClOm

German KL: 23 c-1/04

Number: 1 170 099

File number: G 32115 IV c / 23 c

Filing date: April 24, 1961

Opening day: May 14, 1964

It is known to use organopolysiloxanes as lubricants to use. They are particularly characterized by good heat resistance, water-repellent, insulating and low-viscosity properties (even at high temperatures). Your consistency can is known to change by adding organic or inorganic fat thickeners. Farther it is already known to use a mixture of two different siloxanes with the addition of fat thickeners to use on an inorganic or organic basis as a lubricant.

Organopolysiloxane-based greases are also often used to lubricate metallic parts used. Although the metallic parts themselves are not attacked by such lubricating greases, However, it has been found that such lubricating greases do not protect metallic parts against the effects of corrosion protect from an oxidizing atmosphere in the desired manner. This is special This is the case with parts made of copper, copper alloys or steel. To eliminate this For lack of corrosion-inhibiting additives have been incorporated into these lubricating greases. These However, additives have an unfavorable effect on the other favorable properties, in particular the Heat resistance, made of organopolysiloxanes.

The object of the invention is therefore to produce a mixture of two different siloxanes existing lubricating grease with the addition of organic or inorganic-based grease thickeners to create that has the favorable properties of the well-known siloxanes and beyond when applied to metallic surfaces, for example made of copper or steel, they protect against corrosion protects.

This object is now achieved according to the invention with a lubricating grease of the type mentioned above solved by using a siloxane mixture consisting of the following compounds:

(1) a known liquid organopolysiloxane the formula

in which R "is the same or different and represents a monovalent halohydrocarbon radical, a monovalent hydrocarbon radical or a cyanoalkyl radical and η is 2.004 to 2.4;

(2) 0.1 to 2 percent by weight, based on (1) a known methyl hydrogen polysiloxane of Organopolysiloxane-based lubricating grease

Applicant:

General Electric Company, Schenectady, NY
(V? L. A.)

Representative:

Diplrlng. M. light,

Munich 2, Sendlinger Str. 55

and Dr. R. Schmidt, Oppenau (Renchtal),

Patent attorneys

Named as inventor:

John Harold Wright, Waterford, N.Y. (V. St. A.)

Claimed priority:

V. St. v. America of May 16, 1960 (29 186) -

formula

(R) ₂ (ROSiO

- Si - O \ —Si (R) ₂ (R ')
CH ₃

in which R and R 'represent a methyl or a phenyl radical, where R and R' can be identical or different, R 'can also mean hydrogen and α is an integer from 10 to 500.

It has been found that the addition of a small amount of a known methyl hydrogen polysiloxane gives the grease corrosion and metal parts preventing properties without affecting the other valuable properties of the grease may be impaired.

Methyl hydrogen polysiloxanes of the above formula (2) are known per se. Furthermore are liquid organopolysiloxanes of the above formula (1) known The radical R "in the formula (1) can be an alkyl radical, aryl radical, aralkyl radical, alkenyl radical or as a monovalent hydrocarbon radical contain a cycloaliphatic radical, as halohydrocarbon radical a haloalkyl or -aryl radical.

409 589/411

In the preferred practice of the invention, the liquid organopolysiloxanes of formula (1) are those in which at least 50% of the organic radicals bonded to the silicon are methyl radicals. The viscosity of this liquid organopolysiloxane depends on its molecular weight and the type of silicon-bonded organic residues. Although any liquid Organopolysi'oxan of formula (1) can be used in the invention are preferably liquids having a viscosity between about 10 and lOOOOOcSt at 25 ^Q C.

These liquid organopolysiloxanes can contain the same or different siloxane units of different types Type and composition included, e.g. B. triorganosiloxane or diorganosiloxane units alone or in conjunction with monoorganosiloxane units. For example, these can be organopolysiloxanes as siloxane units, trimethylsiloxane, methylphenylsiloxane, diphenylsiloxane, triphenyl ao siloxane, methyl-jö-xyanoäthylsiloxan-, Methylsiloxan-, Phenylsiloxane or ß-cyanoethylsiloxane units contain.

According to the invention, all these organic or inorganic thickeners can be used as fat thickeners Base can be used. The nature (consistency) of the lubricating greases according to the invention depends on the amount and type of thickener used and the particular liquid used Organopolysiloxane of the formula (1) and the methyl hydrogen polysiloxane (2) used in each case. Examples of suitable thickeners include the metal salts of fatty acids with at least 8 carbon atoms, whereby the metal of the salts consists of aluminum, lead, zinc, manganese, lithium, Sodium, potassium, calcium, barium, strontium, copper, mercury, bismuth, chromium, iron, cobalt, Nickel can exist. The use of many such metal salts is described in U.S. patents 2,456,642 and 2,599,984. Metal salts with fatty acids of a shorter chain, e.g. B. with 2 to 6 carbon atoms, and with oxyfatty acids or oxyfatty acid glycerides, which are described in the U.S. Patents 2,551,931 and 2,508,741 can also be used as thickeners will.

Other particular metal salts used as thickeners in accordance with the invention are lithium 2-ethylhexoate, lithium oxystearate, lithium myristate and lithium caproate. Even Phthalocyanine is a suitable thickening agent.

In addition to the metal salts, one can use as a thickener for the lubricating grease according to the invention use finely divided, neutral oxides of metals and metalloids, e.g. B. silicon dioxide, Aluminum dioxide, iron oxide, titanium dioxide and zinc oxides. Used silica as a thickener used, then the application in the form of an airgel is recommended; but one can also be sublimated or add precipitated silica or diatomaceous earth.

In addition, complex metal soaps can be used within the scope of the invention, e.g. B. Aluminum benzoate stearate in U.S. Patent 2,599,553; Acylureates, e.g. B. Octadecanoylureate according to U.S. Patent 2,698,300 and phenylenediamides, e.g. B. Acetylstearoyl-p-phenylenediamide according to U.S. Patent 2,709,157.

Another particularly advantageous group of thickeners consists of ureas with aromatic Substituents.

Although, as discussed above, the amount of thickener added in the fat masses according to the invention is not critical and can be varied within wide limits (depending on of the desired quality of the end product), it has been found that the Amount usually between about 2 and 25 weight percent based on the weight of the Organopolysiloxane of the formula (1) should be. However, the amount of the used is more decisive Methyl hydrogen polysiloxane (1), which is used as an inhibitor against corrosion. To a To achieve satisfactory corrosion resistance, the methyl hydrogen polysiloxane must be about 0.1 to 2 percent by weight, based on the weight of the liquid organopolysiloxane of the formula (1). Will If less than 0.1 percent by weight of liquid methylhydrogen polysiloxane is used, then the corrosion prevention is used insufficient against copper, copper alloys and steel. If the proportion of methyl hydrogen polysiloxane is more than 2 percent by weight, z. B. 3 weight percent, then the methyl hydrogen polysiloxane itself causes corrosion the copper, copper alloy or steel surfaces.

The greases according to the invention can be prepared in a conventional manner by only the methyl hydrogen polysiloxane of the formula (2), the organopolysiloxane of the formula (1) and the thickening agent is mixed in one of the usual mixing or grinding devices. Particularly Good results have been obtained when the mass is in one of the usual dye or colloid mills was mixed.

If desired, further conventional additives can be added to the lubricating greases according to the invention will.

In the examples below, the grease was prepared by mixing the liquid methyl hydrogen polysiloxane (1), the liquid organopolysiloxane of formula (2) and the thickener in a paint mill. The mixture was milled until a uniform product was obtained. The corrosion resistance of each grease was determined by applying a coating of the composition on a freshly cleaned, sanded and polished copper strip was immersed in water below and as long remained at a temperature of 70 ⁰ C in the water, was observed to corrosion. The corrosion was indicated by the fact that the copper strip had noticeably discolored compared with the fresh copper strip. If a copper strip was immersed in water without any grease coating, it became discolored after 4 hours.

example 1

A number of lubricating greases are prepared by using a dimethylpolysiloxane with a stopped chain (by trimethylsiiyl) with a viscosity of 30OcSt at 25 ⁰ C as the base liquid, each containing 10 percent by weight, based on the weight of the liquid mentioned, of finely divided silicon dioxide aerogel as a thickener. Part of this grease is made without any additive

of an inhibitor retained for comparison. The remaining part be a liquid methylhydrogenpolysiloxane (2) having a viscosity of about 20 cSt at 25 ⁰ C, which contains a stopped by trimethylsilyl chain and an average of about 40 Dimethylwasserstoffsiloxaneinheiten per molecule, were added different amounts. The table below lists the various greases and their test results (according to the test procedure described).

Table I.

attempt
No. Methyl-
hydrogen-
polysiloxane
Addition in
Weight percent Result 1 without addition discolored after 18 hours 2 0.05 discolored after 24 hours 3 0.1 purely after 100 hours 4th 0.5 purely after 100 hours 5 1.0 purely after 100 hours 6th 2.0 purely after 100 hours 7th 3.0 discolored after 48 hours 8th 50 discolored after 30 hours 9 98 discolored after 30 hours

As shown in Table I above, the grease discolored without methyl hydrogen polysiloxane within 18 hours. The mass with an addition of 0.05 percent by weight methyl hydrogen polysiloxane In contrast, shows no appreciable improvement, since it changes color after 24 hours. In contrast to these test results, the greases of the invention are which Containing 0.1 and 0.5 percent by weight methyl hydrogen polysiloxane, still flawless after 100 hours. If a larger amount of methyl hydrogen polysiloxane was added, then a significant amount was found Decrease in corrosion resistance. Will be other common inhibitors to corrosion Added instead of the methyl hydrogen polysiloxane, then the results are also unsatisfactory. For example, if a nonylphenyl is added, the copper strip changes color within 72 hours. With the addition of one of the following, previously used as a corrosion inhibitor The compounds used change the color of the copper strips in less than 50 hours: ethylenediaminetetraacetic acid, their di-, tri- and tetrasodium salts, 2,6-di-tert-butylhydroquinone, anthraquinone, 2-aminoanthraquinone, 2,3-dichloro-1,4-naphthoquinone, dichlorohydroquinone, 3,5-dimethylphenol and Zinc naphthenate.

Example 2

15 contains by weight percent, based on the polysiloxane, lithium-2-ethylhexoate and different amounts of a methylhydrogenpolysiloxane of formula (2), the average of 1,000 methylhydrogensiloxane units per molecule and having a viscosity of 1000 cSt at 25 ⁰ C was added. Table II below gives the test results for these greases.

Table II

attempt
No. methyl
hydrogen
polysiloxane in
Weight percent Result 10 without addition discolored after 12 hours 11 0.05 discolored after 18 hours 12th 0.1 purely after 100 hours 13th 1.0 purely after 100 hours 14th 2.0 purely after 100 hours 15th 3.0 discolored after 24 hours

If the greases of tests 10 and 13 are applied to a wrought iron plate, then shows in the plate coated with the grease No. 10 after 30 hours below those described Experimental conditions discoloration while that coated with No. 13 grease Plate is still flawless even after 100 hours.

Example 3

A liquid methyl phenyl polysiloxane is used as the base, which is a copolymer of dimethylsiloxane and methylphenylsiloxane with abgestoppter by trimethylsilyl chain, in which the ratio of Dimethylsiloxanzu methylphenylsiloxane 3: 1, and the viscosity of the liquid 50OcSt at 25 ⁰ C. The grease is made by ■ mixing this liquid with 10 percent by weight of a urea with aromatic substituents (4,4'-bis- [3-p-toluylurcid]) as a thickener and with different percentages, based on the weight of the liquid, of the methyl hydrogen polysiloxane of the formula ( 2) prepares. The test results of these differently composed lubricating greases are similar to those of Examples 1 and 2. After 100 hours, no discoloration of the test strips is observed if the methyl hydrogen polysiloxane content is between 0.1 and 2 percent by weight, while discoloration occurs in less than 50 hours, if less or more when this amount of methyl hydrogen polysiloxane is added.

Example 4

The base liquid is a copolymer of 10 mol percent methyl-ß-cyanoethylsiloxane units, 80 mol percent dimethylsiloxane units and 10 mol percent diphenylsiloxane units with a chain stopped by trimethylsilyl and which has a viscosity of 25 cSt at 25 ^° C. In the case of lubricating greases which are obtained by adding 25 percent by weight, based on the weight of the base liquid, silicon dioxide (as airgel) and different amounts of the methyl hydrogen polysiloxane from Example 2, results comparable to the previous examples are achieved in the test. In addition, less than 0.1 percent by weight methyl hydrogen polysiloxane content in these greases when tested on a forge

iron stripes discolour after less than 50 hours. Is the addition of methyl hydrogen polysiloxane between 0.1 and 2 percent by weight based on the weight of the base liquid, then the iron is flawless even after 100 hours.

The above exemplary embodiments have illustrated some possibilities of the invention. In addition, the invention is broadly applicable to lubricating greases made with methyl hydrogen polysiloxanes of formula (2) in an admixture of 0.1 to 2 percent by weight, based on the weight of the organopolysiloxane will. The respective liquid organopolysiloxane of the formula (1) used as the grease base used can be of any type. All known thickeners can be used in the same way are used for the production of the lubricating greases, the proportion of which is only depends on the desired consistency of the final product.

Claims (3)

Patent claims: 1. Organopolysiloxane-based lubricating grease, consisting of a mixture of two different types Siloxanes with the addition of fat thickeners on an inorganic or organic basis, characterized in that the SiI-oxane mixture consists of the following compounds: (1) a known liquid organopolysiloxane of the formula a monovalent hydrocarbon radical, a monovalent halohydrocarbon radical or represents a cyanoalkyl radical and is 2.004 to 2.4; (2) 0.1 to 2 percent by weight based on (1) a known methyl hydrogen polysiloxane the formula (R) ₂ (ROSiO Si - Of - Si (R) ₂ (R ') CH ₃ in which R and R 'represent a methyl or a phenyl radical, where R and R' can be identical or different, R 'can also mean hydrogen and a is an integer from 10 to 500. 2. Lubricating grease according to claim 1, characterized in that (1) a liquid dimethylpolysiloxane with chain terminated by trimethylsilyl and (2) a methyl hydrogen polysiloxane with chain stopped by trimethylsilyl. 3. Lubricating grease according to claim 1 or 2, characterized in that the thickener is a Silica airgel is. Considered publications: 'n SiO ₄ - * U.S. Patent Nos. 2,595,890, 2,642,395, 35,2771422, 2,913,473;
^z French patent specification No. 1,099,659; in which R "is the same or different and Swiss Patent No. 300 602. 409 589/411 5.64 Θ Bundesdruckerei Berlin