Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Reexamination Certificate
2000-02-25
2001-08-07
Johnson, Jerry D. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
C508S532000, C508S583000
Reexamination Certificate
active
06271183
ABSTRACT:
FIELD OF INVENTION
The present invention relates generally to emulsifiable oils used in metal working and more particularly to improvements in emulsifiable oils used in machining graphite containing metals, especially cast iron.
BACKGROUND OF INVENTION
Gray and malleable cast iron typically contain between about 2 to about 5 wt % carbon as graphite. In fact, gray cast iron is so-called because when it is fractured the exposed interior surface is gray in color due to the graphite.
In machining metal parts a lubricating composition normally is used to serve not only as a lubricant but also as a coolant and to promote tool cleanliness. Conventional water mix lubricating compositions used in metal cooling consist of a base oil such as a petroleum basestock, a surfactant system, a corrosion inhibition system and a biocidal system. In use, the lubricating composition is mixed with water in the range of about 2 vol % to about 20 vol % oil to form an oil-in-water emulsion.
Experience has shown that in machining cast iron, such as gray cast iron, small particles of graphite are released into the emulsion and result in the formation of a black paste in the oil phase which not only is difficult to clean up but tends to foul the machine tool. This causes long machine tool downtime for tool changes and maintenance. Thus, there is a need for an emulsifiable lubricating composition which tends to reduce, if not prevent, graphite paste formation when the composition is used in machining graphite containing metals such as of cast iron.
SUMMARY OF INVENTION
Accordingly, in one embodiment an emulsifiable lubricating oil composition for use in machining graphite containing metals comprises a major amount of a paraffmic oil of lubricating viscosity, at least one surfactant in an amount sufficient to render the oil emulsifiable in water and from about 0.8 vol % to about 3 vol % of an aliphatic alcohol having from 1 to about 8 carbon atoms.
DETAILED DESCRIPTION
The emulsifiable lubricating oil composition of the present invention includes a major amount of a paraffinic oil of lubricating viscosity. Preferably the paraffinic oil is a basestock having the properties shown in Table 1.
TABLE 1
Broad Range
Preferred Range
KV @ 40° C. cSt
7-100
20-25
KV @ 100° C. cSt
2-12
3-6
KV @ 100° F. SUS
50-470
90-120
Viscosity Index
45-100
75-90
Pour Point, ° C.
−50 to +9
−20 to −9
Flash Point COC, ° C.
150-300
190-220
The composition of the present invention includes at least one surfactant, and may include a mixture of surfactants, in an amount sufficient to render the oil emulsifiable in water. Suitable surfactants are those typically used in emulsifiable oils for metal working such as alkali metal sulfonate and napthanates, fatty acids and the like. Especially preferred is a mixed sulfonate and naphthenate emulsion system with added fatty acid. Typically the surfactant or mixture of surfactants will be present in an amount ranging from about 12 vol % to about 26 vol % based on the total volume of the composition.
Importantly, the compositions of this invention include from about 0.8 vol % to about 3 vol %, based on the total volume of the composition, of an aliphatic alcohol having 1 to about 8 carbon atoms. Isopropanol is particularly preferred.
The composition of the present invention may also include biocidal agents and antifoamants.
Table 2 sets forth several especially useful compositions in accord with the invention.
TABLE 2
Component
Vol % Range
Vol % Preferred
100 P Base Oil
(1)
30-96
81.80
Surfactant
(2)
12-25
15.75
Surfactant
(3)
0.05-1.0
0.50
Antifoamant
(4)
0.01-1.0
0.60
Isopropanol
0.3 to 3.0
1.35
(1)
A paraffinic lubricating base oil having KV @ 40° C. of 22 cSt.
(2)
A mixed sulfonate and naphthenate emulsion system sold under the name Polartech 6090P/M0085 by Polartech, Dundas, Ontario, Canada.
(3)
A tall oil fatty acid sold under the name Pamak 4 by Hercules Corp., Wilmington, Delaware.
(4)
An ethylene bis-stearamide antifoamant sold under the name Discotech 5898 by Calloway Chemical, Columbus, Georgia.
REFERENCES:
patent: 3719598 (1973-03-01), King
patent: 4849122 (1989-07-01), Imai et al.
patent: 5171903 (1992-12-01), Koyama et al.
patent: 5817605 (1998-10-01), Papay
patent: 6063261 (2000-05-01), Baca
Allocca Joseph J.
ExxonMobil Research and Engineering Company
Johnson Jerry D.
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