Note: Descriptions are shown in the official language in which they were submitted.
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INTRODUCTION
In the metalworking industry it is now a co D n practice to use a
variety of metalworking coolants. These coolants function in two manners,
name:ly to dissipate heat from the work surface and the tool, and to lubricate
the interface between the work surface and the tool, thereby extending tool
life and improving the general characteristics of the finished workpiece.
Metalworking coolants are used in a variety of metalworking and finishing
operations which are normally performed on such typical machines as lathes,
drill presses, automatic chuckers, milling machines, screw machines, grinders,
saws, lapping machines and the like.
A frequently used fluid is an oil type metalworking coolant or
fluid. These oil type metalworking coolants are usually composed of a mineral
oil or lubricating oil base into which has been incorporated one or more
additives to improve the metalworking characteristics and lubricity of the
oil. A typical oil type metalworking coolant or lubricant would have the
following formula:
FO ULA I
Sulphurized Oil 0 - 25%
tveg. animal or pet. base)
Chlorine containing ccmpound 0 - 25%
(veg. animal or pet. base)
Wetting Agent O - 5%
(anionic-amides or sod. sulphonate)
(nonionic-ethoxy or propoxy compounds)
(anionic-amine salts of fatty acids as
TEA oleate, etc.)
Bactericide-Fungicide 0 - 2%
(innumerable)
Metal Deactivator 0 - 2%
Anti Oxidant O - 1%
Corrosion Inhibitor 0 - 2%
(amines, oxazolines, etc.)
Hydrocarbon Ealance
(Mineral Seal oil, kerosene, high flash
paraffin oils, napthenic oils)
-- 1 --
B~
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The application of thcse oil type metalworking coolants is
accomplished by taking a hoselike nozzle and applying a stream
of the coolant directly to the area between the tool and the
workpiece. As the metalworking coolant contacts the work surface
or the tool, one of which is usually moving in a rotational
manner, the metalworking coolant tends to be thrown from the
rotational workpiece or the tool which is being rotated due to
the action of centrifugal force. This results in metalworking
coolants being removed from the workpiece or tool in the form of
fine droplets. Also, the metalworking coolant is frequently
dissipated from the area to which it is applied due to the splash
which occurs on the fluid contacting the surfaces to which it is
applied, Due to the phenomenon of loss of metalworking fluid
due to centrifugal force and splashes loss, substantial quantities
of the fluid are lost into the atmosphere rather than being
utilized in cooling and lubricating the tool and workpiece. In
certain limited applications these fluids are applied in the
form of fine mists which tend to dissipate into the atmosphere
much of the fluid before it contacts the tool or workpiece.
If it were possible to treat oil type metalworking fluids
of the type described with a chemical composition which would
allow the fluid upon contact with either the workpiece and/or the
tool to be more firmly adhered thereto by the dimunition of the
splash and centrifugal force effects, less fluid would be needed
in metalworking operations of the type described. Such an additive
should not only improve the losse$ occasioned by splashing and
centrifugal force but it should not adversely affect the cooling
and lubricity factors of the oily metalworking fluid. If such an
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l l
additive wer~ available, an improvement in the art of metalworking
would be afforded.
THE INVENTION
The invention relates to an improved method of working
metals. It is particularly directed to metalworking processes
of the type wherein a tool contacts a work surface and an oily
metal coolant is used to cool and lubricate the interface between
the tool and work surface. This type of metalworking operation
is substantially improved in accordance with the invention if
the oil type metalworking coolant used contains at least 5 ppm
of an oil-soluble polymer formed by the polymerization of at least
one monoolefinic compound through an aliphatic unsaturated group,
said polymer having a molecular welght of at least 25,000. Upon
application to the metal surface, e.g. the workpiece and/or the
tool~ the adherence of the oil type metalworking coolant or fluid
to the metal surface is substantially increased.
THE OIL-SOLUBLE POLYMERS
The oil-soluble polymers used in the invention should have a
molecular weight of at least 25,000. Preferably the molecular
weight is in excess of 100,000 and most preferably the molecular
weight is 1,000,000 or more.
It is greatly preferred that the polymeric additive
be soluble in the oil component. It is, therefore, preferable
that the polymer be derived from a hydrophobic monomer. Examples
typical of these are styrene, alpha-methylstyrene, vinyl toluene,
chlorostyrene, vinyl acetate, vinyl chloride, vinyl formate, vinyl
alkyl ethers, alkyl acrylates, alkyl methacrylates, ethylene,
propyl e, n-butylene, isob~tylene, etc ~he most pre~erred oil-
161466~47
soluble polymers have a molecular weight in excess of 100,000.These polymers which have sh~own the greatest measure of success
have a linear hydrocarbon structure derived from an ethylenically
unsaturated monomer containing 2-5 carbon atoms. These monomers
may contain one or two unsaturated groups. Among these, poly-
ethylene, polypropylene, polyisobutylene, polybutadiene, poly-
isoprene and copolymers thereof have shown the most promise.
Polyisobutylene and polyisoprene (natural rubber) are the most
preferred of this group.
By the term "soluble," as applied to the property of the
polymers of the invention of being able to be incorp~ ated into
oil type metalworking coolants, is meant the ability of being
solubilized or dispersed in at least use amounts in the liquid
being treated.
Depending upon the nature of the polymer, its molecular
configuration, molecular weight, etc., the dosage may be varied
over a considerable range. Thus, in the most preferred practice
of the invention the oil type metalworking coolant should contain
between 15-500 ppm of the polymer and most preferably the polymer
dosage is within the range of 100-500 ppm.
An important concept of the invention resides in the fact
that the amount of polymer used should not substantially increase
the viscosity of the oily metalworking lubricant into which it
is incorporated. This is extremely important since the invention ;
works by what is believed to be a heretofore unknown mechanism.
Prior art lubricants which contain polymers of the type described
are usually so treated with such polymers to improve their vis-
cosity indices which infers a substantial thickening of the
` 1f~46~47
lubrican~ into ~hich such polymers are placed.
In most instances the viscosity of this starting oily
metalworking lubricant will not be increased more than 10-20%
by the addition of the polymers thereto, If viscosities in
excess of this amount are obtained, it is found that the oily
metalworking lubricants while tending to show more adherence
characteristics to the workpiece or tool are more difficult to
pump and handle as well as having decreased spreading properties
¦ which substantially diminishes their usefulness.
! EVALUATION OF THE INVENTION
¦ To evaluate the invention the following test setup was
used: ¦
Into a commercial lathe was chucked a three-inch diameter
steel bar which was one foot long. The lathe was equipped with
a supply hose for directing coolant onto the workpiece and the
lathe cutting tool. The speed of the workpiece was set at 900
rpm and the cutting tool set at a rake angle of 30 with the
feed rate being relatively moderate.
The oil type coolants used in the experiment had the
following formula:
FORMULA II
Sulfurized fatty oil 8.33
Chlorinated Paraffin 2.98
¦ Sulfurized Pale Oil 62.02
3% Solution of Polyisobutylene 0.70
(Molecular Weight 1,000,000 dissolved
in mineral seal oil)
(Methyl esters of palmitic
& oleic acids) 4.17
Mineral Seal Oil 21.00
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This formula was flooded onto thc workpiece and tool durins
the cutting operation which lasted 3 minutes. A strobe li~ht was
set up and adjusted to allow visible observation of the droplets
and splash patterns generated by the application of the coolant.
¦ IDbservations were made of this run. An identical run was made
~ using the above formula with the exception that the
¦ polyisobutylene polymer was omitted.
¦ In comparing the above two runs, it was noted that the
¦ presence of the polymer reduced splash and droplet formation due
¦ to centrifugal force by about 60%.
An important feature of Formula II is that the
incorporation of the polyisobutylene into the formula in the
amount shown did not materially increase the viscosity of the
formula. This data is presented below: ¦
Vis. at 100F. Vis. at 210F. Viscosity
Product SUS SUS Index
,,
Formula II `
w/o Polymer 100.2 40.4 128
Formula II 102.1 40.7 124
PRIOR ART
U.S. 2,431,008 U.S. 2,876,199
U.S. 2,356,367 U.S. 3,413,109
U.S. 2,487,260 U.S. 3,408,175
Having thus described our invention, it is claimed as
follows:
