US2625509A - Cutting fluid and coolant - Google Patents

Description

Patented Jan. 13, 1953 CUTTING FLUID AND COOLANT Ernst Laug, Union City, N. J assignor to Socony- Vacuum Oil Company, Incorporated, a corporation of New York No Drawing.

Application March 20, .1950,

Serial No. 150,823

This invention relates to an aqueous composition of matter adapted, particularly in diluted form, for use as a coolant and lubricating agent in metal cutting and similar operations.

In the machining of metals in operations such as cutting, threading, tapping, and the like it is customary to flood the tool and work with a coolant to carry away heat from the tool and work, and normally such coolants are also so compounded as to lubricate the operation. Due to the high unit pressures involved, particularly in high speed operations, the fluid, if used also as a lubricant, must be an exceptionally capable lubricant. Many such fluids are emulsified petroleum oil base fluids, although in some cases it would appear that non-petroleum base fluids are more acceptable. The present invention is found in the latter field, i. e., the non-petroleum base lubricants.

It is an object of this invention to provide a novel cutting and coolant fluid of the class described in the form of an aqueous emulsion, capable of being used either as formed or in dilute form, preferably in dilute form, which will be effective as a coolant and lubricant under the conditions noted.

Another object is the provision of such a fluid incorporating optimum proportions of emulsifying soaps and lubricating agents. Still another object is to provide a stable, non-corrosive, rustinhibiting water-base metal processing lubricant. Still other objects will'appear hereinafter.

The above and other objects are accomplished by the provision of an-aqueous emulsion of mixed soaps of castor oil fatty acids, with certain glycols, phosphates, and inhibitive agents.

The compositions of matter with which this invention is concerned are specifically emulsions containing, in combination, potassium soaps of castor oil fatty acids, triethanolamine soaps of castor oil fatty acids, triethanol amine phosphates, water soluble polyalkylene glycols, and inhibitive substances.

Typical formulations of the composition will fall within the following ranges:

(8) Water Balance to 100% Norr..TEAis an abbreviation for triethanolamine.

" '3 Claims. (01.252-343) The above formulation is unique in that, in addition to the characteristics furnished by the individual components, various combinations of the components either amplify individual characteristics or impart entirely new properties to the product. As illustrations, the following may be cited. It is understood, of course, that these observations apply only to the combinations which exist in this particular formulation.

1. The combination of potassium castor oil soap, triethanolamine castor oil fatty acid soap, water soluble polyalkylene glycol and triethanolamine phosphate-results in a product, water solutions of which, on drying, leave a soft, residual film.

2. The combination of water soluble polyalkylene glycols and triethanolamine phosphates imparts greater film strength characteristics to the product than the use of either one alone. This same combination acts also as an efiicient foam depressor.

3. The combination .of triethanolamine phosphate and sodium nitrite is a better inhibitor against corrosion of ferrous metals than either material alone.

4. The water-soluble polyalkylene glycols, besides imparting film strength to the product, are also good lubricity agents.

5. Sodium mercaptobenzothiazole prevents corrosive action on copper, brass, bronze and allied metals by the soaps present in the composition. Furthermore, thismaterial possesses some germicidal properties.

A composition within the above defined field may be made by compounding together the following ingredients:

TABLE II I Weight percent Castor oil 13.50 Castor oil fatty acids 1.75 Potassium hydroxide 2.75 'I'riethanolamine 11.50 phosphoric acid 2.25

Nora-The polyalkylene glycol constituent used above is one supplied under the Carbide and Carbon Chemical Corp. trade name of Ucon 50 HB 5100 and is a commercial polyalkylene glycol product having a Saybolt viscosity of 5000- 5200 at F. and 013165- at 210 R, an average specific gravity of about 1.063, apour 3 test of about 20 F. and a flash of about 450 F. Generally similar products will be similarly useful.

This material may be compounded by charging the castor oil to an agitated, steam-jacketed kettle, and heating to about 110 to- 120 F. Then the potassium hydroxide (a 50% water solution) may be added slowly with stirring. The temperature of the soap thus formed is gradually raised to about 180 F. and agitation is continued for about one and one-half hours, until saponification is completed. With continuing agitation, the triethanolamine is added, followed by the polyalkylene glycols and the phosphoric acid. After about half an hour further stirring, the batch is allowed to cool to about 120 F. Water is added slowly to prevent excessive foaming and stirring is continued, with slight heating, if necessary until the solution is clear. Then the sodium nitrite is added, and when it is dissolved, the sodium mercaptobenzothiazole and phenol are added. After stirring until thoroughly homogenized, the batch may be drawn.

The above procedure yields a lubricant base coolant composition having the following characteristics TABLE III Color Light brown (clear) Odor Slightly germicidal Specific gravity 60 F--- 1.078 Stability upon freezing' Satisfactory Reaction Neutral pH 1-15 distilled water 8.25

This composition of matter is preferably used as a coolant and lubricant for metal working in diluted form, the following having been found to be advisable proportions:

TABLE IV Operation Dilution Tapping l-lO to l-l5 Drilling." 1l5 to l-25 Grindingslunc l-50 to l-60 When so used, the material is found to be a quite eflicient coolant andlubricant, as shown b'y the following:

Tapping test Standard. Socony-Vacuum Solvac 4l0-1-15 tap water 100%.. Test. Composition of Table 11-1-15 tap water Almen pin test In the Almen pin test, a standardized test current in the trade, the composition of Table II, diluted 1-15 with tap water, was found to bear an OK load'of 30,000 pounds per square inch.

Drilling test In this test, a commercial high speed: drill", diameter, is run to failure, drilling through 4 a thick plate of SAE 3140 steel. The composition of Table II, diluted 1-15 with tap water, was found to yield 156 holes to drill failure.

Corrosion E? Reagivc um: 1 y 70 F., 12 hours l-l5 tap water Nil.

l-30 tap water Nil.

1-45 tap water Nil.

1-60 tap water Nil.

ll00- tap water Iraco The composition is stable when diluted with hard water, since when diluted 1-15 with a water of 200 p. p. m. or less hardness, not more than a slight cloud will be formed.

In compounding materials of the kind disclosed herein, certain items of importance should be noted.

First, the total amount of soaps may vary from about 18 per cent to about 24 per cent, and the proportion of triethanolamine soap should be great enoughto plasticize the potassium soap without giving rise to excessive foaming. This will be accomplished by from about 2 per cent to about 5 per cent ofthe total.

The action of the triethanolamine phosphate upon solubility of the glycols limits the amount of thismgredientto not over about 13 per cent.

The polyalkylene glycols appear to be most effective at-about 4 per cent.

The sodium nitrite corrosion inhibitor and phenol germicide may be replaced by other materials of similar capabilitv.

The inherent capability of these compositions resides in the combination of soaps, phosphate, and glycols particularly, and the broadest form of the invention therefor may be said to be embraced in compositions made by compounding together.

TABLE-V I V 7 Weight percent Potassium soaps of castor oil fatty I claim:

1. An aqueous emulsion-form coolant and lubricant composition of matter produced by compounding together Weight percent Potassium soaps of castor oil fatty acids 17 to 20 Triethanolamine soaps of castor oil fatty acids 2 to 5 Triethanolamine phosphat 3 to 13 Water soluble polya'lkylene glyco1s' 3 to 5 Rust inhibitive salts of sodium 2.25 to 4 Phenol germicide 1 to 1.5 Water To balance 2 An aqueous emulsion-form coolant and lubricant composition of matter produced by compounding together Weight percent Potassium soaps of castor oil fatty acids 17 to 20 Triethanolamine soaps of castor oil fatty acids 2 to 5 Triethanoiamine phosphate 8 to 13 Water soluble polyalkylene g1yco1s 3 to 5 Sodium mercaptobenzothiazole (solution--45-50%) 0.75 to 1.5 Sodium nitrite 1.5 to 2.5 Phenol 1 to 1.5 Water To balance 3. An aqueous and emulsion-form coolant and lubricant composition of matter produced by saponifying the castor oil and castor oil fatty acids with potassium hydroxide, adding triethanolamine to the reaction mixture, then adding glycols, phosphoric acid, sodium nitrite, phenol, sodium mercaptobenzothiazole solution, and the required amount of water, thus compounding together REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,238,478 Ott Apr. 15, 1941 2,252,385 Orozco Aug. 12, 1941 2,291,066 Waugh July 28, 1942 2,318,629 Prutton May 11, 1943 2,470,913

Bjorksten May 29, 1949

Claims (1)

1. AN AQUEOUS EMULSION-FORM COOLANT AND LUBRICANT COMPOSITION OF MATTER PRODUCED BY COMPOUNDING TOGETHER