US3311557A

US3311557A - Lubricant for rolling metals

Info

Publication number: US3311557A
Application number: US414869A
Authority: US
Inventors: Knapel F Schiermeier; Clark W Judd
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1964-11-30
Filing date: 1964-11-30
Publication date: 1967-03-28
Anticipated expiration: 1984-03-28
Also published as: CH481208A; AU6407065A; BE673031A; DE1594595A1; NL6515452A

Description

United States Patent O 3,311,557 LUBRKCANT FOR ROLLING METALS Knapcl F. Schiermeier and Clark W. Judd, Alton, 11]., assiguors to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 30, 1964, Ser. No. 414,869 12 Claims. (Cl. 25234) This application is a continuation-in-part of application Serial No. 309,297, filed Sept. 16, 1963, now abandoned.

This invention relates to improved lubricants, more particularly, it relates to aqueous base lubricants designed especially for use in hot rolling non-ferrous metals, such as aluminum.

It is well known from the prior art that non-soluble oils such as straight mineral oils or their emulsions are unsatisfactory as lubricants for the hot rolling of nonferrous metals such as aluminum. Straight mineral oils or composite mineral oils lack the required cooling properties since the temperature encountered during the hot rolling of aluminum is in the range of from about 300 F. to about 900 F. To take advantage of the lubricating qualities of oils, emulsions have been tried for this purpose. Emulsions are generally prepared by mixing a soluble oil with a large proportion of water, for example, from 10 to 50 parts of water per part of oil. Conventional soluble oils for hot rolling aluminum are generally composed of light viscosity mineral oil, petroleum sulfonates, resin soaps or soaps derived from fatty acids, coupling agents, wetting-out agents, and a small proportion of water in neat oil. Although emulsions are good coolants, they have a disadvantage in that they cause staining of the worked surfaces and also cause so-called metal pickup. This phenomenon is the appearance of nodules or accretions of metal on the surfaces of the rolls. ,The accretions build up, causing sticking and deformation, which at times become serious enough to cause shutdown and require regrinding of the rolls. In addition to the loss of time and money, spoilage and waste of metal are the results of improper lubrication.

It has now been discovered that a soluble oil for compositing with water and which results in an excellent lubricant for the hot rolling of non-ferrous metals such as aluminum is provided by a mineral lubricating oil containing an additive combination comprising a minor amount of each of an alkanolamine soap of a fatty acid, free fatty acid, and an alkylene polyol. The concentration of each additive in the soluble oil is critical for achieving excellent performance of the final composition in providing good cooling and lubricating properties, bright surface finish, and resistance to staining and metal pick-up.

The mineral oil used as the base for the soluble oil should be a HVI lubricating oil, i.e. one having the viscosity index (Dean-Davis) of at least 80, preferably 90- 100. Mineral oil fractions of this type are derived from paraffinic, naphthenic or mixed base crudes. Viscosity as determined at 100 F. is in the range from about 75 to 250 SUS, preferably between 100 and 150. A typical mineral base of this kind is a high viscosity index refined mineral lubricating oil having the following properties:

GR, API, 60 C. 32.2 Color, ASTM 1 Pour point, F. Q. 5 Flash, F. COC 370 Fire, F. 435 Viscosity, SUS at 100 F. 103 Viscosity index 93 Neutralization number 0.01

Patented Mar. 28, 1967 The low viscosity index oils (10-50 VI) are generally unsuitable for use as the mineral oil base for the soluble oils of the present invention.

The fatty acid used in the present composition includes fatty acids of from 12 to 30, preferably 14 to 18 carbon atoms and may be derived from animal, vegetable or mineral sources, such as fatty acid obtained from cotton seed oil, soy bean oil, coconut oil, corn oil, palm oil, lard oil, tallow and pure saturated and unsaturated fatty acids, such as stearic, oleic or linoleic acids. Oleic acid or mixed fatty acids having a high proportion of oleic acid are particularly suitable because of low melting point. A suitable fatty acid is sold by Emery Industries under the trade name of Emery 3305, the major constituents and approximate amount being oleic acid (45% wt.), stearic acid (15% wt.), linoleic acid (15% wt.), and palmetic acid (15% wt.). A particularly suitable fatty acid is Emery 3252 which is of low melting point and results in an oil blend of low pour point. The amount of fatty acid used in the soluble oil is from about 10% to about by weight and preferably from about 15% to 25% by weight.

Of the akanolamines, the lower alkanolamines, such as the ethanolamines, are suitable. Such alkanolamines react readily with the fatty acid. Excellent results are obtained with diethanolamine, which is relatively inexpensive and readily available. Only sulficient alkanolamine is used to react with a portion of the fatty acid so as to leave a relatively large amount of free fatty acid in the soluble oil, e.g., sufiicient alkanolamine is used to react with on the order of from about 15-40% of the fatty acid. The amount of the alkanolamine is controlled so that the ratio of the total base neutralization number-electrometric (T BN E as determined by the ASTM 664 method) to the total acid neutralization number-electrometric (TAN-E as determined by the ASTM 664 method) of the soluble oil is in the range from about 0.15 to 0.4 and preferably from 0.15 to 0.3. When this ratio is too low, emulsions of the soluble oil with water may have poor stability. At high ratios, pick-up of aluminum fines by the emulsions may become excessive.

Alkylene polyols suitable for use in the composition of the invention are those wherein the alkylene group has from 4-8 carbon atoms. Particularly suitable and preferred alkylene polyols are the diols, such as hexylene glycol, 1,2-hexane diol, 1,5-pentane diol, 1,5-hexane diol and the like. From about 2 to 8% by weight of the alkylene polyol is used in the soluble oil.

Other additives can be added to compositions of this invention in order to improve their performance. For example, emulsious containing fatty acids are susceptible to deterioration, especially when used at elevated temperatures for long periods of time. Such emulsions develop an extremely strong, foul and undesirable odor which renders them objectionable. It is generally desirable to add a small amount of a germicidal agent to inhibit bacterial growth and fermentation. Formalin (aqueous solution of approximately 40% formaldehyde) and phenolic compounds, e.g. phenol, chlorophenols such as tetrachlorophenol, phenyl phenols such as o-phenyl phenol, and the like are well known germicidal agents. The phenolic germicidal agents are preferred and are available commercially. The amount of germicidal agent used generally does not exceed 5% by weight, usually from (ll-1% by weight added to the soluble oil is very effective. Minor amounts, e.g., 0.11% by weight of antitoxidants can be used. A highly suitable antioxidant is 2,6-ditertiary butyl-4-methyl phenol.

Illustrative examples of soluble oils of this invention comprise:

Composition A- Percent Weight Germicidal agent (0.25% wt. Dowicide C.O.

+0.25% wt. Dowicide 6) 0.5

Composition D- Emery 3305 fatty acid 18.0 Diethanolamine 2.3 1,5-pentane diol 3.9 Mineral lubricating oil (same as A) 75.8

Composition E- Emery 3252 fatty acid 25.0 Diethanolamine 1.5 Hexylene glycol 7.5 Mineral lubricating oil (same as A) 66.0

Plus 0.5% by Weight 2,6-ditertiary butyl-4- methyl phenol and 50 p.p.m. by weight Dow Corning Antifoam A.

In preparing the soluble oil, the fatty acid and a portion of the glycol are mixed and heated to about 170 F. The ethanolamine is added and the temperature is increased to about 180 F. which is maintained for about 1 /2 hours to react the fatty acid and the ethanolamine. The reaction mixture is blended with the oil at about 100120 F., followed by the addition of additives such as antioxidants, antifoam agents and the like. The remainder of the glycol is added and mixed for about /2 hour. Mechanical agitation is used for mixing.

sions form quite readily, which is an important factor since the mixing of the oil and water is done in the field by means such as air agitation, propeller mixing and the like. The composition of the emulsion yields a proper balance among the forces of attraction operating between the oil and Water phase, the oil phase and the metal, and the water phase and the metal. The composition of the emulsion is such that an oil-in-water emulsion and a Water-in-oil emulsion are almost equally likely to form spontaneously, yet the resulting emulsion is quite stable. To illustrate the properties of the composition of the present invention, a comparison is made with a soluble oil comprising:

Percent Weight Mineral lubricating oil (VI 94, 105 SUS 100 F.) 62.9

*The soluble oil base is: Percent weight soidiunilnsulfonates (40% wt. sodium sulfonutes n o Hexylene glycol 3.0 Triethanolamine 2.3 Oleic acid 1.6 Water 6.8

Properties of Composition A and Composition E of the invention and the comparative oil is given in Table I.

TABLE I Composition Composition Compara- A E E tive Oil 1 i Gravity, API 29. 5 29. 4 f 20. 0 Four Points, 35 10 -15 Flash, 000, F 265 235 30a Viscosity at 100 F., SUS-.. 134 113 750 Initial p 7. 9 7. 7 TEN-132..-- 9.2 7.4 25.0 TAN-E 25. 5 44. 3 22. 0 Ratio TBN-E/TAN-E 0. 36 0. l7 1. 14 Saponification No., mg.

KOH!g 29. 2 46. 0 Ash 0. 01 0. 002 1. 33 Water, percent wt Trace 0. 6

Emulsion stability is indicated by preparing an emulsion of oil (6% v.) and distilled Water and measuring separation of oil and water from a 100 cc. sample at the end of four hours. Affinity of the oil for metal is demonstrated by a test wherein aluminum fines (95% thru 200 mesh, 80 to 90% thru 325 mesh) are mixed (0.1% wt. of emulsion) at room temperature with an emulsion of oil (6% v.) and distilled water and the separation rate of the fines is determined by sampling the emulsion, filtering the sample, and weighing the amount of aluminum recovered from the sample. Comparative results from these tests are given in Table II for Composition A and the comparative oil.

TABLE II Aluminum suspended, percent I oi Emulsion Emulsion Stability seperation in 4 hours Aluminum Sediment on bottom 1 Includes approx. 0.060% w. zinc soaks.

Finished emulsions are prepared by admixing, on a volume basis, from about 2% to about 10%, preferably about 3% to 6% soluble oil with Water. In general, the present soluble oils can be used in concentrations lower than those used with conventional soluble oils From the results presented in Table II, it can be seen that the emulsion prepared from Composition A of the present invention is more stable and markedly superior with respect to metal pickup than that from the comparawhich is advantageous from a cost standpoint. The emultive oil composed of conventional soluble oil additives.

EXAMPLE I emulsion.

EXAMPLE II Composition E was similarly used in concentrations ranging from about 2.5% to 5% by volume oil with excellent results. Quality of rolled strip was quite good even for high magnesium content alloys such as 5052 and 5252. After three weeks of operation, about -20% by volume of the emulsion was withdrawn each week and replaced with fresh emulsion to extend service life. Ash content due to build-up of aluminum fines suspended in the emulsion was 0.030% to 0.040% by weight. In contrast, ash content of a commercial soluble oil (typical properties are a ratio TBN-E/TAN-E of 0.57, saponification No. 26.9, and 25.8 API gravity) reaches about 0.120% in 3-4 weeks and is discarded. The pH of the emulsion is relatively constant at about 7 which shows good resistance to air oxidation. Bacteria count is quite low at about 2 million which is in marked contrast to the 100-200 million often obtained with the commercial soluble oil. A commercial germ-icide (Tris Nitro sold by Commercial Solvents Company) of 0.01% by weight is maintained in the rolling oil. Low emulsion concentrations are used and excellent emulsion stability is obtained, compared with commercial oil. Thus, superior performance of the soluble oil of the present invention compared with the commercial oil commonly used is demonstrated.

We claim as our invention:

1. A soluble oil suitable for use in hot rolling non-ferrous metals which consists essentially of a major amount of a mineral lubricating oil having a viscosity index of at least 80 and a viscosity at 100 F. of from about 75 to about 250 SUS, from about 10% to about 30% by weight of fatty acid having from 12 to 30 carbon atoms, from about 2.0% to about 8.0% by weight of an alkylene polyol wherein the alkylene group has from 4 to 8 carbon atoms, and an ethanolamine in an amount to provide a ratio of the total base numberelectrometric to total acid numberelectrometric in the range from about 0.15 to *2. A soluble oil suitable for use in hot rolling non-ferrous metals which consists essentially of a major amount of a mineral lubricating oil having a viscosity index of at least 80 and a viscosity at 100 F. in the range from about 100 to about 150 SUS, from about 10% to 30% by weight of a fatty acid having from 14 to 18 carbon atoms, from about 2.0% to about 8.0% by weight of an alkylene diol having from 4 to 8 carbon atoms, and an ethanolamine in an amount to provide a ratio of the total base number-electrometric to total acid number-electrometric in the range from about 0.15 to 0.3.

3. The soluble oil of claim 2 containing from about 0.1% to 1% by weight of 2,6-ditertiary butyl-4-methyl phenol.

'4. A soluble oil suitable for use in hot rolling aluminum which consists essentially of a major amount of a mineral lubricating oil having a viscosity index of at least 80 and a viscosity at 100 F. in the range from about to 250 SUS, from about 10% to 30% by weight of a fatty acid having from 14 to 18 carbon atoms, from about 2.0 to 8.0% by weight of an alkylene diol having from 4-8 carbon atoms, and diethanolamine in an amount to provide a ratio of the total base numberelectrometric to total acid numberelectrometric in the range from about 0.15 to 0.4.

5. The soluble oil according to claim 4 wherein the alkylene diol is hexylene glycol.

'6. A soluble oil suitable for use in hot rolling aluminum which comprises a major amount of a mineral lubricating oil having a viscosity index of at least and a viscosity at F. of from about 100 to about SUS, about 25% by weight of a fatty acid having from 14 to 18 carbon atoms, about 7.5% weight hexylene glycol, and about 1.5% by weight diethanolamine.

7. An aluminum hot rolling lubricant composition comprising a major amount of water and from about 2% to 10% by volume of the soluble oil of claim 1.

8. An aluminum hot rolling lubricant composition comprising a major amount of water and from about 2% to 10% by volume of the soluble oil of claim 2.

9. An aluminum hot rolling lubricant composition comprising a major amount of water and from about 2% to 10% by volume of the soluble oil of claim 3.

10. An aluminum hot rolling lubricant composition comprising a major amount of Water and from about 2% to 10% by volume of the soluble oil of claim 4.

11. An aluminum hot rolling lubricant composition comprising a major amount of water and from about 2% to 10% by volume of the soluble oil of claim 5.

:12. An aluminum hot rolling lubricant composition comprising a major amount of water and from about 2% to 10% by volume of the soluble oil of claim 6.

References Cited by the Examiner UNITED STATES PATENTS 2,846,393 8/1958 Cook et al. 25249.5 X 2,913,411 11/ 1959 Schiermeier 252-495 X 2,981,128 4/ 196 1 Flemming 252-49.5 X 3,071,544 1/1963 Rue 25249.5 X

FOREIGN PATENTS 241,332 11/1962 Australia.

DANIEL E. WYMAN, Primary Examiner.

- C. F. DEES, Assistant Examiner.

Claims

1. A SOLUBLE OIL SUITABLE FOR USE IN HOT ROLLING NON-FERROUS METALS WHICH CONSISTS ESSENTIALLY OF A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL HAVING A VISCOSITY INDEX OF AT LEAST 80 AND A VISCOSITY AT 100 F. OF FROM ABOUT 75 TO ABOUT 250 SUS, FROM ABOUT 10% TO ABOUT 30% BY WEIGHT OF FATTY ACID HAVING FROM 12 TO 30 CARBON ATOMS, FROM ABOUT 2.0% TO ABOUT 8.0% BY WEIGHT OF AN ALKYLENE POLYOL WHEREIN THE ALKYLENE GROUP HAS FROM 4 TO 8 CARBON ATOMS, AND AN ETHANOLAMINE IN AN AMOUNT TO PROVIDE A RATIO OF THE TOTAL BASE NUMBER-ELECTROMETRIC TO TOTAL ACID NUMBER-ELECTROMETRIC IN THE RANGE FROM ABOUT 0.15 TO 0.4.