US2205990A - Pipe thread lubricant - Google Patents

Description

atented June 25 1940 PIPE THREAD LUBRICANT Roy F. Nelson and William S. Hurwitz, Port Arthur, Tex., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application January 15, 1938,

Serial No. 185,157

9 Claims.

This inventionrelates to lubricating and coatng compositions containing one or more metals :1 finely divided form. More particularly, the nvention relates to compositions of matter vhich are useful for application to pipe threads nd the like to prevent seizing, galling and strip- :ing. Compositions which comprise a lubriating base composed of oil and a metal soap, and a soft metal in powdered form, such as commercial powdered zinc or lead, are typical.

In the construction of pipe lines, in the oil and iatural gas industries, for example, a large numer of relatively diflicult problems have been en- :ountered. One such problem which has caused :onsiderable difiiculty is encountered especially n the uncoupling of large sized threaded pipe oints. Such joints, after having been united or a short time, tend to freeze or grip tightly, he threads seize and stripping usually results. it has been recognized for some time that a pedal type of lubricant is required for such breaded joints and a considerable number haveeen proposed in the art.

Most of the pipe thread lubricants heretofore lIOpOSed have included one or more powdered aolids dispersed in various types of lubricating ases. In some of the compositions of this type, Jarticularly those containing powdered zinc, it 1as been found that upon standing for a period lf time gas bubbles appear in said compositions md there is a tendency for the compositions to team and to expand. This is undesirable as it s necessary to allow space for expansion in the :ontainers in which the compositions are haniled and marketed. It is also necessary to provide openings in said containers for the escape if, said gases. The quality and stability of such ompositions may be aifected adversely by the formation and escape of gases therefrom, and accordingly said compositions may be improved my preventing the formation of said gases.

The reason for the formation and escape of gases from such compositions is not definitely Known. Some of the gasesv so produced have seen collected, however, 1 and found to contain substantial quantities of hydrogen and of air. it has also been found that powdered zinc reacts with a number of the constituents of such compositions to produce hydrogen. The following combinations of materials, for example. were mixed with zinc dust:

Petroleum lubricating oil and water Petroleum lubricating oil, water and lime Petroleum lubricaing oil, water and high acid tallow Petroleum lubricating oil and high acid tallow Petroleum lubricating oil and lime High acid tallow High acid tallow and water Petroleum lubricating oil, aluminum sulfate and water Petroleum lubricating oil and aluminum sulfate Petroleum lubricating oil, aluminum s1 -.t

and water Petroleum lubricating oil and aluminum stearate Petroleum lubricating oil, stearic acid and water Petroleum lubricating oil and stearic acid Petroleum lubricating oil, sodium sulfate and water Petroleum lubricating oil and sodium sulfate Stearic acid and water Stearic acid In each case there was evidence of some type of reaction occurring in these mixtures within 48 hours of the mixing. In the case of the fluid mixtures, evolution of gas was noted by the bubbles developed in the liquid. In the mixtures containing fat, which were solid, evidence of reaction was noted by the swelling of the mixtures and apparent formation of gas pockets which may or may not have been hydrogen. It was observed that in mixtures of zinc dust and petroleum lubricating oil no gas was formed.

In the paint industry diillculty has been experienced in connection with the formation and escape of gases from coating compositions containing powdered zinc and drying oils such as linseed oil.

We have discovered that the formation and escape of gases from compcsitions of this type can be effectively prevented by introducing into the composition a small amount of nitrobenzene.

In a specific embodiment of our invention a pipe thread lubricant may be prepared, as follows:

A calcium soap grease of the type which is used in grease cups and the like may be prepared by saponifying tallow with lime, this saponification being preferably conducted under steam pressure and in the presence of a small proportion of a petroleum lubricating oil. Upon release'of the steam pressure an additional quantity of the petroleum lubricating oil may be worked into the mixture to produce a grease having the desired consistency. Finally} zinc dust and a small amount of nitrobenzene may be mixed with the grease to produce a composition suitable for use as a pipe thread lubricant. The pipe thread lubricant above described may contain, for example, the following ingredients, by weight:

Per cent Cup grease 40 to Zinc dust to Nitrobenzene 0.15

A cup grease may be used which has, for example, the following analysis: Consistency, (A. S. T. M. method), unworked sample 300-360 Melting point 210 F. minimum Calcium soap 10-14% Free alkalinity, Ca(OH)-2 0.2% maximum Foreign mineral matter 0.1% maximum Free fatty acid, oleic 0.2% maximum Free neutral fat (Sap. No. 196) 2.0% maximum Water 2.0% maximum Mineral oil 81.7% minimum Zinc dust may be used which has, for example, the following analysis:

Total zinc 97.2% Metallic zinc 97.0% Zinc oxide 4.0% Iron and aluminum oxide 1.6% Nickel Negative Copper Negative Chromium Negative Barium Negative Calcium Negative Lead Negative The finished pipe thread lubricant may have, for example, the following specifications:

Consistency (A. S. T. M. meth- Other metal soaps may be used in preparing the lubricant base of these lubricants, including alkali metal, alkaline earth metal, and aluminum soaps.

It is possible to vary the proportions of the aaoaeec various ingredients employed in our composition to a considerable extent. The amounts shown in the above examples are only illustrative. For example, the metal powder inthe composition may range from about 10 per cent. to about per cent. The proportion of petroleumlubricating oil may vary according to the consistency desired in the finished product. The amount of nitrobenzene which is required may vary, but ordinarily about 0.10% to 1.0% will be suflicient.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and only such limitations should be im osed as are indicated in the appended claims.

We claim:

1. composition of the character described comprising an oil and powdered zinc which normally tends to deteriorate and form gas on standing. and a small amount of nitrobenzene effective to stabilize said composition against such gas formation.

2. A pipe thread lubricantcomprising a' lubricating base such as a metal soap grease, a metal powder containing powdered zinc and a small amount of nitrobenzene.

A pipe thread lubricant comprising a calcium soap grease, a metal powder containing powdered zinc and a small amount of nitrobenzene.

4. A pipe. thread lubricant comprising an aluminum soap grease, a metal powder containing powdered zinc and a small amount of nitrobenzene.

5. A pipe thread lubricant comprising from about 40% to about 45% of a calcium soap grease, from about 55% to about 60% of powdered zinc and a small amount of nitrobenzene.

6. A pipe thread lubricant comprising from about 40% to about 45% of a calcium soap grease, from about 55% to about 60% of powdered zinc and about 0.15% of nitrobenzene.

7. A pipe thread lubricant comprising from about 40% to about 45% of a calcium. soap grease, from about 55% to about 60% of powdered zinc and from about 0.1% to about 1.0% of nitrobenzene.

8. A composition of the character described comprising a drying oil such as linseed oil, powdered zinc and a small amount of nitrobenzene.

9. In stabilizing a composition of the character described comprising an oil and. powdered zinc, which. tends to deteriorate and form gas on standing, the method which comprises adding thereto a small amount of nitrobenzene.

ROY F. NELSON. WILLIAM S. HURWITZ.