US2447483A

US2447483A - Additives for silicone oils

Info

Publication number: US2447483A
Application number: US531241A
Authority: US
Inventors: Hayward R Baker; William A Zisman
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1944-04-15
Filing date: 1944-04-15
Publication date: 1948-08-24
Anticipated expiration: 1965-08-24

Description

ZAQFAW DETS FOR SEKCONE &8

ayward R. Baker, Mount inier, Md and William A. Zlsman, Washington, D. 0., ass ore to the United States of? America as represented by the Secretary oi the Navy No Drawing. Application r Se No. 8313M 4 ClasiCll. 252-49.8)

(Gted under the act of March 3. 1888, as amended April 30, 1928; 370 Q. G. 757) This invention relates to anti-corrosion addi- A tives for use with silicone oils, and to these oils containing the same.

In the efifort to find more nearly ideal lubricants than the petroleum hydrocarbons, especially in respect of inilammability, and also viscosity at low temperatures, a new type of oil, or series of oils, has been developed wherein silicon plays an important part in the molecular structure. These oils, briefly, are polymers of various organic silicon derivatives, such as the alkyl silicon halides, and they are known as the silicone oils.

In spite of their unusual physical properties, these oils, by themselves, are rather limited in application because they are relatively corrosive when compared with the best protected hydro- 7 carbon oils.

This invention provides a group of organic compounds which are soluble and compatible with the silicone oils at high and low tempera= tures and which inhibit the corrosive action of the oils when dissolved therein in small quantities. The invention also includes these oils containing the anti-corrosion additives referred to. as new compositions of matter.

Not all organic compounds which are soluble in these oils are capable of inhibiting their corrosive action. The group of the compounds which are effective may be classified generally in the form ofseveral sub-groups, namely: naphthenic acids having molecular weights between about 180 and about 400, metal naphthenates of these acids, and derivatives of saturated and unsaturated aliphatic hydrocarbons having chains of to 18 carbon atoms. the derivatives being chosen from the group of unsubstituted amines monocarboxylic acid derivatives, metal and amine soaps of said monocarboxylic acid derivatives, aryl, chloraryl, alkaryl and hydroaryl substituted monocarboxylic acid derivatives.

Typical, preferred compounds within these groups are described more in detail as follows:

The aliphatic series of acids from capric to palmitic protects steel from corrosion when in a mixture of silicone oil and water. However, larger quantities of the shorter chain acids are required to give the same protection as the longer chain ones. All of this series are recommended for temperatures above 0 F. except palmitic acid '2 which is suitable for temperatures above 32 F.

Unsaturated acids like stearolic acid, 9-octadecynolc acid, are suitable if usediat temperatures above 0 F., as are related acids of the unsaturated group with less carbon atoms.

Substituted aliphatic acids including chlorophenyl, benzyl, xylyl, tolyl and naphthyl substituted aliphatic acids up to the stearic acid derivative are suitable corrosion inhibitors for use at temperatures not lower than minus 20 F.

Tetrahydronaphthyl stearic acid and related hydrogen substituted phenyl, xylyl and tolyl substituted aliphatic acids are recommended for use over the temperature range of about minus 40 F. to about F.

Ethylphenyl stearic acid and related compounds from methyl to octadecyl, phenyl, benzyl, tolyl, xylyl and naphthyl substituted aliphatic acids from capric to stearic acid are excellent anti-corrosion additives for use at temperatures not lower than about 0 F. for the long chain compounds to as low as minus 40 F. for the shorter chain compounds.

Aromatic substituted aliphatic acids, such as phenyl undecylic acid and xylyl undecylic acid, are satisfactory additives at temperatures as low as minus 40 F., and their related acids such as I the phenyl. benzyl, tolyl, xylyl and naphthyl substituted aliphatic acids are also useful. The shorter chain acids are most useful at low temperatures, and the longer chain ones at temperatures down to about0 F.

Naphthenic acids having molecular weights between about 188 and 400 have proven very effective at both high temperatures and at temperatures below minus 40 F.

The aliphatic amines from dodecyl to octodecyl amine are satisfactory down to about 0 F.

Metal naphthenates, such as compounds of aluminum, nickel and manganese, inhibit corrosion but are not soluble in the silicone oils much below 32 F. Other compounds suitable for use above about 32 F. include trihydroxyethylamine stearate and metallic soaps such as zinc myristate, magnesium stearate, tin stearate and copper oleate.

Mixtures of any of these additives may be used in the silicone oils to achieve characteristics dependent on more than one type of additive.

A comparison of the eflects of difierent specific additives on silicone oils is shown in the following table, the meaning of the abbreviations being given below.

4 as a corrosion inhibitor, from about 0.1% to about 2.0% by weight of a fatty acid having from about 10 to about 18 carbon atoms in its chain.

Corro- Percent Effect of Cold Silicone Solubility in Additive sion Additiv btorage i112 oil used Rating by weight Silicone Oil weeks Caprlc acid 60%3-3 D. C 0.5 51 cl 0 F. Lam-lo acid" 60-3-4 D. O 2 0. 1 s1 cl 0 F. M rlstic acid 00-3-3 D. C 1 0. I si cl 0 F. Pn. mitic acid... 60-3-3 D. O-.. 0 0.2 sl cl 32 F. HLoarollc acid 60-3-2 D. C-.. H 0. 2 cl 010 F. Chlorophenyl steoric acid 60-3-3 D. C. 0 0.1 s] cl 20 F. ii thylphcnyl stcnric acid 0-39 G. E. 0 0.3 :1 cl 0 F. 'loiruhydronaphthyl stem-i0 acl 60-3-3 D. C 0 0.6 s -40). Phcnyl umiccyllc a 60-3-1 D. C 0 0.3 s 40g. .\yl vl undccylic acid 00-3-2 D. O-.. 16 0.2 s -40 Naphthcnic acid M. W. 240. 60-3-1 D. C 56 0.3 8 --40). Nuphthcnic acid M. W. 188, 60-3-1 D. C 1s 0.3 S 40). n hvvuivcyi amine 00-3-1 D. C... i 0.2 sl cl-0 F. \lnm'uum nnphthcnate 60-3-3 D. 0.- 2 0.02 s1 cl 32 F. Niiliiii nnpllthcnate 60-3-1 D. C it 0.1 i32 F. Manganese nnphthennte 00-3-3 D. lie 0. 2 s1 010 F. 'lrillydroxycthylamine stearate 60-3-3 D. C 0 0.2 p. 132 F. Zinc myristata 00-3-3 D. C 2 0. 1 100 C sl cl 0 F. Magnesium stearata 60-3-1 D. C it 0. l p. a. 100 C 132 F. 'liu stearate 60-3-3 D. 0.. 0 0. 2 p 8. 100 C 132 F. Copper olcate 60-3-3 D. 0... M0 0.2 p s 100 l32 F.

s=soluhlc; i-insoluble s1 cl slightly cloudy p. s.=purtly soluble The corrosion rating was determined by a modification of the A. S. T. M. turbine corrosion test D-665-42T. The modification consisted of using a flat bottom Pyrex cylindrical container 80 by 18 mm. in size. The specimen was a piece of cold rolled steel 4.25 by 0.25 by 0.03 inch in size. The specimen'was attached directly to the shaft of a motor and served as its own stirrer, revolving at approximately 1080 R. P. M. The lower 1.78 inches of the specimen is the only part considered in the test as it alone is in contact with the liquid sample. The sample consists of 9 parts by volume of silicone oil, 1 part of distilled Water containing the additive compound. thus giving a mixture of 90% silicone oil and about 10% water. The steel specimen was rotated in the mixture for 48 hours at 140 F.

Many variations will be apparent to those skilled in the art, and the invention should not be limited other than as defined by the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

1. A hydraulic and lubricating fluid composition comprising essentially a silicone fluid and from about 0.1% to about 2.0% by Weight of a corrosion inhibiting compound selected from the group consisting of fatty acids, chloroaryl substituted fatty acids, alkaryl substituted fatty acids and. hydroaryl substituted fatty acids wherein the fatty acid chain contains from about 10 to about 18 carbon atoms.

2. A hydraulic and lubricating fluid composition comprising essentially a silicone fluid and,

D. C.=-Dow Corning G. E.=Gencral Electric ,3. A hydraulic and lubricating fluid composition comprising essentially a silicone fluid and, as a corrosionanhibitor, from about 0.1% to about 2.0% by weight of an alkaryl substituted fatty acid having from about 10 to about 18 carbon atoms in its chain.

4. A hydraulic and lubricating fluid composition comprising essentially a silicone fluid and, as a corrosion inhibitor, from about 0.1% to about 2.0% by weight of a chloroaryl substituted fatty acid having from about 10 to about 18 carbon atoms in its chain.

HAYWARD R. BAKER. WILLIAM A. ZISMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date- OTHER REFERENCES Dow Corning Fluids, bulletin by Dow Corning Corporation, Midland, Mich., 8 pages. Feb. 17. 1945.

The American Magazine. Oct. 1942, page 149.