DE1228363B - Organopolysiloxane copolymers as lubricating grease - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

/ »Ilk,

GERMAN mj9W> PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
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ClOm

German KL: 23 c - 1/04

1228363
G37976IVc / 23c
June 18, 1963
November 10, 1966

It is known to use organopolysiloxanes as lubricants. Ibxe consistency can be known to change by the addition of organic and ^ ₇ Anorga ruffles grease thickeners. Furthermore, it is already known to use a mixture of two different SiI-oxanes with the addition of fat thickeners on an organic or inorganic basis as a lubricant. _y . '. ■

, Organopolysiloxane-based greases are also often used to lubricate metallic parts used. It is true that the metallic parts themselves are not attacked by such lubricating greases. It. However, it has been found that metallic parts are not protected against corrosion by such lubricating greases Influences are protected in the desired way. This is especially true for those made of copper, Copper alloys or steel existing parts the case. In order to remedy this deficiency, up to now Corrosion-inhibiting additives incorporated into the lubricating grease. These additions each have an effect but unfavorable on the properties, in particular the heat resistance, of the organopolysiloxanes the end.

It has now been found that this disadvantage does not occur when a copolymer of the formula.

Organopolysiloxane copolymers

as grease ^:

Applicant : _,; .

General Electric Company,

Schenectady, N, Y. (V. St. A.)

Representative:

Dipl.-Ing. M. Licht, Dr. R. Schmidt,

Dipl.-Wirtsch.-Ing. A. Hansmann

and Dipl.-Phys.S. Herrmann, patent attorneys,

Munich 2, Theresienstr. 33

As an inventor; named:

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

Claimed priority:

V. St. v. America June 25, 1962 (205 064) - -

(R ') ₂ (R ") SiO -

ΓΗ ■ '1
1 · ■ ■ - ■ R. I.
Si-O
I. b Si-O
I. I ■■■ '. ···
CH3 I.
R.

in dex R a monovalent, optionally halogenated hydrocarbon radical or cyanoalkyl radical, R 'a methyl or phenyl radical, R "a methyl, phenyl or hydrogen radical and b at least equal to 1, c at least equal to 1 and b + c is at least equal to 10, together with a thickener and optionally a polysiloxane of the formula

ν ·. ·, · ..., ■■

' ¹ R ₄ SiO ₄ -n
2

in which R has the above meaning and η has a value between 2.004 and 2.4, the proportion of methyl hydrogen polysiloxane units in the copolymer being 0.1 to 2 percent by weight of the total weight of the copolymer and polysiloxane, is used as the lubricating grease.

The polysiloxanes used are preferably those in which at least 50% of the silicon-bonded organic radicals are methyl radicals. Liquid polysiloxanes which have a viscosity of between approximately 10 and 100,000 cSt ^{at 25 ° C. are also preferred.} The optionally used liquid organopolysiloxanes can contain identical or different siloxane units of different types and compositions, for example triorganosiloxane or diorganosiloxane units alone or in conjunction with monoorganosiloxane units.

The usual thickeners can be added to the copolymer to achieve the required consistency be added on an organic or inorganic basis. Examples of suitable thickeners include the metal salts of fatty acids with at least 8 carbon atoms.

Although the amount of thickener added is not decisive and within wide limits can be varied, it has been found that the amount is usually between about 2 and 35 percent by weight, preferably 2 to 25 percent by weight, based on the weight of the polysiloxanes in the Should be fat.

In order to achieve a satisfactory corrosion resistance, must - based on the weight of the Copolymer and the polysiloxane - about 0.1 to 2% methylhydrogensiloxane units are present be. With less than 0.1% methyl hydrogen polysiloxane units Inadequate corrosion prevention in contact with copper, copper

609 710/272

alloys and steel observed. If the proportion of methyl hydrogen polysiloxane units is more than 2 percent by weight, then it was found that the methyl hydrogen polysiloxane itself corrode the Copper, copper alloy or steel surfaces that the grease comes into contact with.

Therefore, the ratio of methylhydrogensiloxane units in the liquid copolymer originally chosen so that the methylhydrogensiloxane units are about 0.1 to 2 percent by weight the total weight of the liquid copolymer or, if a polysiloxane is present, of the total weight of the two components.

The claimed lubricating greases are produced in the usual way by mixing.

Other common additives can be used, for example, to improve lubricity and durability be added to the fats.

The following exemplary embodiments are intended to explain the implementation of the invention in more detail. In each case the fat mass was prepared by mixing the liquid polysiloxanes with the thickener in a paint mill. The mixture was milled until a uniform product was obtained. The corrosion resistance of each composition was determined by applying a coating of the composition on a freshly cleaned, sanded and polished copper strip was immersed subsequently in water at a temperature of 70 ⁰ C and as long as remaining 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, then it discolored after 4 hours,

Example- 1 ^:

A liquid methylhydrogensiloxane / dimethylsiloxane copolymer chain stopped by trimethylsilyl units was obtained by hydrolyzing and condensing a mixture of methylhydrogen dichlorosilane and dimethyldichlorosilane and trimethylchlorosilane prepared in a conventional manner. the The proportions of the various chlorosilanes were similar selects that the resulting liquid polysiloxane is 0.5 percent by weight methylhydrogensiloxane, starting by weight of the liquid, and had a viscosity of about 25'cSt at 25 ° C. Through this a substance was created with a trimethylsilyl stopped Chain, which on average is a copolymer of methylhydrogensiloxane and dimethylsiloxane units was. A silicone grease was prepared from this liquid by adding 10 parts by weight a finely divided silica airgel as a thickener with 100 parts of the liquid mixed. Such a fat mass was subjected to the corrosion resistance test described above then it was found that the copper strip was still flawless after 100 hours had elapsed.

Example 2

Copolymers of dimethylsiloxane and methylhydrogensiloxane units were produced by the method of Example 1 with a chain stopped by trimethylsilyl units which had a viscosity of approximately 25 cSt at 25 ° C and contained 1.0, 5.0, 10.0 and 20.0 weight percent methyl hydrogen polysiloxane. From these Liquids, fats were made by adding a portion of each liquid to a dimethylpolysiloxane with chain stopped by trimethylsulyl units and a viscosity of 300 cSt in the manner added that a content of 0.5 percent by weight methylhydrogensiloxane, based on weight of liquids. Each fat mass contained IQ percent by weight based on weight of liquids, a finely divided silica airgel as a thickener. Each of these Fats were subjected to the above-described test for corrosion resistance on a copper base, and each sample was still flawless after 100 hours.

Claims (1)

Claim: Use of a copolymer of the formula (R ') ₂ (R ") SiO- H -. [R 1
I. Si-O Ί
Si-O
1 CH ₃ I.
R. SifR ') ₂ (R ") in which R is a monovalent, optionally halogenated hydrocarbon radical or cyanoalkyl radical, R 'is a methyl or phenyl radical, R "is a methyl, phenyl or hydrogen radical and b is at least 1, c is at least 1 and b + c is at least 10 are, together with a thickener and optionally a polysiloxane of the formula R ₄ SiO ₄ - ,, in which R has the above meaning and η has a value between 2.004 and 2.4, the proportion of methyl hydrogen polysiloxane units in the copolymer being 0.1 to 2 percent by weight of the total weight of the copolymer and polysiloxane, as a lubricating grease. Considered publications:
German patent specification No. 1170 099. 609 710/272 11.66 © Bundesdruckerei Berlin