Note: Descriptions are shown in the official language in which they were submitted.
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
LUBRICANTS SUITABLE FOR HYDROFORMING AND OTHER METAL
MANIPULATING APPLICATIONS
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. Application Serial
No. 09/957,911 filed September 21, 2001 which, in turn, claims the benefit of
U.S.
Provisional Application Serial No. 60/234,833, filed September 22, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to lubricants used in metal forming processes
and, in particular, to lubricants used in hydroforming processes.
2. Background Art
Processes in which metal parts are manipulated or formed typically
require lubricants to reduce equipment wear. These processes include such
operations as bending, swaging, roll-tapping, drawing, and hydroforming.
Hydroforming is a particularly important process in which a relatively complex
metal part is fabricated.
There are two types of hydroforming processes. One is used to form
parts from sheet metal and the other is used to form parts from metal tubes.
Many
tube hydroforming applications are currently utilized by the automotive
industry.
In a tube hydroforming process, a workpiece tube is placed in a tool
cavity. The geometry of the die cavity corresponds to the external geometry of
the
produced part. The tool cavity is closed by the ram movement of a press. At
the
same time, the tube ends are loaded by two punches moving along the tube axis,
and
-1-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
an aqueous fluid is pumped into the tube. As the internal pressure of this
pressure-
side aqueous fluid is increased, the tube expands until the expanding tube
wall
contacts the inner surface of the die, and the part is formed.
There are three types of lubricants involved in the tube hydroforming
process: a bending lubricant, the pressure-side aqueous fluid mentioned above,
and
a die-side lubricant that is used between the workpiece tube and the die. The
bending lubricant is used on the inside of the tube to bend the tube into a
desired
shape just prior to mounting the tube in the hydroforming tool cavity. The
pressure-
side fluid is the aqueous hydraulic fluid used to transmit the pressure to the
inside
of the tube. Although little lubricity is required of the pressure-side fluid,
other
properties, such as corrosion protection, high pressure stability, and the
ability to
reject the bending and die-side lubricants, are important to the performance.
The
die-side lubricant is the primary forming fluid in high-pressure hydroforming.
It
provides the lubricity between the workpiece and the die.
The demands on the die-side lubricant vary widely. Some light duty
applications require little of the die-side lubricant. In the case of lower
pressure
applications, the pressure-side fluid may also be used simultaneously to
transmit
pressure inside the tube and to provide die-side lubrication. As the
complexity of
the application increases, the importance of the die-side lubricant increases.
Furthermore, the die-side lubricants' compatibility with the pressure-side
lubricant
and the removal of the die-side lubricant from the newly formed part are
important
considerations .
SUMMARY OF THE INVENTION
The present invention discloses a liquid film die-side hydroforming
lubricant that comprises an oil and a surfactant. The liquid film die-side
lubricant
is typically already a liquid when applied to the workpiece tube. Preferably,
the
liquid film die-side lubricant has lubrication properties that are not
substantially
-2-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
damaged by contact with the pressure-side fluid which usually contains water.
Furthermore, the liquid film die-side lubricant preferably has high viscosity.
In accordance with another aspect of the present invention, a solid
film die-side hydroforming lubricant is disclosed. The solid film die-side
lubricant
comprises a wax such that the stress value within the die-side lubricant is at
least
540 kPa at 0.75 sec after a compressive stress is imposed. Preferably, the
solid film
die-side lubricant is a liquid when applied to the workpiece tube. The applied
liquid
then either dries or cures into a solid lubricating film. The solid film die-
side
lubricant has lubrication properties that are not substantially damaged by
contact
with the pressure-side fluid, which usually contains water. Furthermore, the
liquid
film die-side lubricant preferably has high viscosity. When the die=side
lubricant
of the present embodiment is a solid at the time of emplacement, the die-side
lubricant preferably has high hardness and optionally a high elasticity. The
solid
film lubricant also optionally includes a wetting agent to improve the ability
of the
composition to wet metallic surfaces.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to presently preferred
compositions or embodiments and methods of the invention, which constitute the
best modes of practicing the invention presently known to the inventor.
For purposes of the present invention, the resistance of a lubricant to
damage to its lubrication properties by pressure-side fluid is most
conveniently
measured by measuring the coefficient of friction of two metal surfaces,
lubricated
with the die-side lubricant to be measured, in a sliding friction test at a
pressure
from 65 to 400 bars and in a twist compression test at a pressure from 675 to
2500
bars. A die-side lubricant to be tested is first placed on one surface of a
substrate
of the same type of metal as is to be hydroformed in the same manner as if the
substrate were to be hydroformed, but the substrate in this instance has a
shape
suitable for the intended method of measurement of coefficient of friction.
After the
-3-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
coefficient of friction has been measured, the die-side lubricant layer is
sprinkled or
otherwise gently wet with the intended pressure-side fluid for hydroforming or
a
surrogate for this pressure-side fluid, plain deionized or tap water often
being an
effective surrogate. A volume of the pressure-side fluid or surrogate therefor
that
is not more than about twice the volume of the wetted die-side lubricant film
itself
should be used, and no substantial mechanical force such as would result from
high
pressure spraying should be used. After a minute or two of contact between the
lubricant layer and the pressure-side fluid or surrogate therefor, any
remaining
aqueous liquid is allowed to drain away under the influence of natural
gravity, and
the coefficient of friction of the substrate bearing the thus-drained die-side
lubricant
film is again measured. The die-side lubricant has sufficient pressure-side
fluid-
resistance for the purposes of this invention when the coefficient of friction
measured with the thus wetted and drained die-side lubricant film does not
exceed
the coefficient of friction measured under the same conditions with the
originally
emplaced and unwetted die-side lubricant filin by an amount that is preferably
more
than about 50 percent of the value of the coefficient of friction for the
originally
emplaced and unwetted die-side lubricant film, more preferably more than about
30
percent of the value of the coefficient of friction for the originally
emplaced and
unwetted die-side lubricant film, and most preferably more than about 1.0
percent
of the value of the coefficient of friction for the originally emplaced and
unwetted
die-side lubricant film. In particularly favorable instances, the coefficient
of friction
is reduced by contact with the pressure-side fluid or surrogate therefor. All
of the
measurements involved in this determination of the pressure-side fluid
resistance of
a lubricant should be made at the intended temperature of the hydroforming
process
itself, or, if the latter is unknown, at a normal ambient human comfort
temperature
(between 18 and 23° C).
In one embodiment of the present invention, a liquid film die-side
hydroforming lubricant is disclosed. The liquid film die-side lubricant is
typically
already a liquid when applied to the workpiece tube. The liquid film die-side
lubricant has lubrication-properties that are not substantially damaged by
contact
with the pressure-side fluid as defined above. Furthermore, the liquid filin
die-side
hydroforming lubricant includes an oil that has a kinematic viscosity measured
at
-4-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
40° C, that is at least, with increasing preference in the order given,
2.5, 5.0, 7.5,
10.0, 12.5, 15Ø 17.5, or 20 stokes. Suitable commercially available oils
include
vegetable oils, blown (alternatively called "oxidized") vegetable oils,
polymers of
vegetable oils, animal oils, and blown animal oils along with typical
petroleum oils.
Specific examples include blown canola oil, blown fish oil, canola oil, blown
rapeseed oil, and naphthenic oil.
The liquid film die-side hydroforming lubricant ("liquid film
composition") of the present invention optionally further include a
surfactant. The
surfactant improves the cleaning properties of the lubricant, i.e., the ease
of
removing residual lubricant. Although any surfactant may be utilized,
preferably
non-ionic surfactants are used. The surfactant also preferably improves the
lubricity
of the liquid film when wetted. Though not restricting the improvement of
lubricity
to any particular mechanism, the surfactant appears to form an emulsified
layer
when wetted that enhances lubricity. However, the amount of surfactant is not
so
much that the liquid film is deteriorated during emulsification. The
surfactant is
preferably present in an amount of 0.1 % to 10 % of the total weight of the
liquid
film composition, more preferably in an amount of 1.0 % to 5 % of the total
weight
of the liquid film composition, and most preferably in an amount of about 2.5
% of
the total weight of the liquid film composition. Preferred surfactants include
vegetable oil ethoxylates, ethoxylates of alkyl alcohols, ethoxylates of
acetylenic
diols, block copolymers of ethylene and propylene oxides, ethoxylates of alkyl
carboxylates such as typical fatty acids, alkyl polyglycosides, and mixtures
thereof.
Examples include but are not limited to Chemal DA-6, Chemal DA-9, Chemal LA-
4, Chemax CO-5, Chemax CO-16, Chemax CO-25, Chemax CO-30, Chemax CO-
36, Chemax CO-40, Chemax CO-80, and Chemax CO-200/50 commercially
available from Chemax, Inc. located in Greenville, SC. Suitable surfactants
also
include but are not limited to Surfynol 440 commercially available from Air
Products, TOMAH E-14-5 (poly (5) oxyethylene isodecyloxypropylamine) and
TOMAH E-14-2 commercially available from Tomah Products Inc. located in
Milton, WI; NINOL 11CM (a modified coconut diethanolamide surfactant sold by
Stepan, Inc.) TRITON X-100 (octylphenol ethylene oxide condensate; Octoxynol-
9)
commercially available from Union Carbide; and APG 325 CS (decyl
polyglucoside)
-5-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
comrriercially available from Cognis Corporation located in Cincinnati, Ohio.
Other
suitable non-ionic surfactants include block surfactants containing
polyoxypropylene
hydrophobe(s) and polyoxyethylene hydrophile(s). In order to properly
function, the
surfactant must be soluble or dispersible in the lubricant. The blocks may be
homopolymeric or copolymeric, for example copolymers derived from
oxyalkylating
with mixtures of ethylene oxide and propylene oxide. Such surfactants are
available
from numerous sources, including the Pluronic~, Tetronic~, and Pluronic~ R
polyether surfactants from BASF Corporation.
In another embodiment of the present invention, a solid film die-side
hydroforming lubricant ("solid film composition") is disclosed. Typically, the
solid
film lubricant will be applied to a surface as a liquid which is subsequently
dried and
cured. The resultant solid lubricant of the present invention preferably has a
hardness as measured at 23-26 ° C by the American Society for Testing
and
Materials ("ASTM") Procedure Number D-5 that is not more than, with increasing
preference in the order given, 50, 40, 30, 20, 15, 13, 11, 9, 7, 5, or 3. The
solid
film lubricant of the present invention includes solid lubricants that are
characterized
by one or more of the following properties when subjected to a compressive
stress
within the range from 1.50 to 2.00 percent over a time interval of 0.20 to
0.30
seconds at 23-26° C:
- the stress value within the solid die-side lubricant
0.75 sec after the compressive stress began to be
imposed is at least, with increasing preference in the
order given, 500, 510, 520, 530, 540, 550, 560, 570,
or 5~0 kiloPascals (this unit of stress being
hereinafter usually abbreviated as "kPa");
- the stress value within the solid die-side lubricant 100
sec, after the compressive stress began to be imposed
is at least, with increasing preference in the order
given, 300, 350, 400, 450, 500, 510, 520, 530, 540,
or 550 kPa; and
- the residual stress within the solid die-side lubricant
100 sec after the compressive stress began to be
-6-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
imposed is at least, with increasing preference in the
order given, 75, 80, 82, 84, 86, 88, or 90 percent of
the maximum stress induced within the solid lubricant
at any time up to 100 sec after the stress began to be
imposed.
A method of measuring these stress values is described by T H. Sheilhammer,
T.R.
Rumsey, and J. M. I~rochia in "Viscoelastic Properties of Edible Lipids,"
JOURNAL
of FOOD ENGINEERING 33 (1997), pages 305 - 320. This paper is hereby
incorporated herein by reference to the extent that it is not inconsistent
with any
explicit statement herein. Preferred solid film lubricants include carnauba
wax;
candelilia wax; montan wax; microcrystalline waxes; solid alcohols,
particularly
primary alcohols having at least 18 carbon atoms per molecule; solid esters,
particularly esters of primary alcohols having at least 18 carbon atoms per
molecule
with organic acids, especially unbranched monoacids, having at least 18 carbon
atoms per molecule; and oxidized petroleum waxes.
The solid film die-side hydroforming lubricant of the present
invention optionally further includes a surfactant. Although any surfactant
may be
utilized, preferably non-ionic surfactants are used. The surfactant also
preferably
improves the lubricity of the solid film when wetted. The surfactant is
preferably
present in an amount of 0.05 % to 10 % of the total weight of the solid film
composition, more preferably in an amount of 0.1 % to 5 % of the total weight
of the
solid film composition, and most preferably in an amount of about 1 % of the
total
weight of the solid film composition. Preferred surfactants include vegetable
oil
ethoxylates, ethoxylates of alkyl alcohols, ethoxylates of acetylenic diols,
block
copolymers of ethylene and propylene oxides, ethoxylates of alkyl carboxylates
such
as typical fatty acids, alkyl polyglycosides, and mixtures thereof. Suitable
surfactants also include but are not limited to Surfynol 440 commercially
available
from Air Products, TOMAH E-14-5 (poly (5) oxyethylene
isodecyloxypropylamine) and TOMAH E-14-2 commercially available from Tomah
Products Inc. located in Milton, WI; NINOL 11CM (a modified coconut
diethanolamide surfactant sold by Stepan, Inc.) TRITON X-100 (octylphenol
ethylene oxide condensate; Octoxynol-9) commercially available from Union
_7_
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
Carbide; and APG 325 CS (decyl polyglucoside) commercially available from
Cognis Corporation located in Cincinnati, Ohio. Other suitable non-ionic
surfactants include block surfactants containing polyoxypropylene
hydrophobe(s)
and polyoxyethylene hydrophile(s). The blocks may be homopolymeric or
copolymeric, for example copolymers derived from oxyalkylating with mixtures
of
ethylene oxide and propylene oxide. Such surfactants are available from
numerous
sources, including the Pluronic~, Tetronic~, and Pluronic~ R polyether
surfactants
from BASF Corporation.
The solid filin die-side lubricant optionally comprises a wetting agent.
Utilization of such agents improves the ability of the dry film composition
(which
is a liquid when applied) to wet metals such as the various steel alloys
(stainless
steel, hot rolled steel, and cold rolled steel), aluminum alloys, titanium,
and
copper. It will be recognized by those skilled in the art, that many wetting
agents
are surfactants and many surfactants are wetting agents. Accordingly, a subset
of
the surfactants listed above will also function as wetting agents. Suitable
wetting
agents include, but are not limited to, nonionic fluorosurfactants, anionic
fluorosurfactants, ethoxylated tetramethyldecynediols, acetylenic glycol-based
surfactants, dialkylsulfosuccinates, and mixtures thereof. Suitable
ethoxylated
tetramethyldecynediols include members of the Surfynol 400 series such as
Surfynol
440 and 420 commercially available from Air Products. An exemplary acetylenic
glycol-based surfactant is Dynol 604 commercially available from Air Products.
Suitable dialkylsulfosuccinates include dioctylsulfosuccinates. The preferred
wetting
agent is a fluorosurfactant which includes both nonionic fluorosurfactants and
an
anionic fluorosurfactants. Most preferably the wetting agent is a nonionic
fluorosurfactant. Suitable nonionic fluorosurfactants include fluoroaliphatic
ethoxylates and related derivatives. Specifically, Clariant Fluowet OTN and
DuPont
Zonyl FSN 100 are nonionic surfactants that performed well. Fluowet OTN is a
proprietary fluoroaliphatic ethoxylate commercially available from Clariant.
Zonyl
FSN 100 is a Telomer B monoether with polyethylene glycol which is a 1:1
mixture
of poly(oxy-1,2-ethandiyl), cc-hydro-S2,-hydroxy-ether with a-fluoro-,SZ-(2-
_g_
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
hydroxyethyl)poly(difluoromethylene).Suitable anionic fluorosurfactants
include
fluoroalkylsulfonates and carboxylates with a range of counter ions that
include
potassium, sodium, and amines. Preferably, the fluorosurfactant is present in
an
amount of about 0.1 % to 1.0% by weight of the dry film composition. More
preferably, the fluorosurfactant is present in an amount of about 0.1 % to 0.5
% by
weight of the dry film composition.
The solid film die-side lubricant also optionally includes a corrosion
inhibitor andlor a defoamer. Suitable defoamers include neo-decanoic acid.
Suitable
corrosion inhibitors include soaps or salts of carboxylic acids or organo-
sulfonates.
Agents capable of adjusting the pH of the lubricant may also be included, such
as,
fox example, amines (e.g., alkanolami~les).
Regardless of whether the die-side lubricant is solid or liquid at the
time of emplacement or whether the die-side lubricant has an aqueous-based
liquid
after being emplaced, the coefficient of sliding friction between two metal
surfaces
with a layer between them of a die-side lubricant to be used in a process
according
to the invention preferably is not more than about 0.3 to 0.5, more preferably
is not
more than about 0.1 to 0.3, and most preferably is not more than about 0.04 to
0.1.
Furthermore, the die-side lubricant is preferably capable of being
readily cleaned from the hydroformed object after hydroforming is complete,
preferably with an aqueous-based cleaner. Preferably, the die-side lubricant
is
capable of being cleaned at a temperature not higher than 55 °C, more
preferably a
temperature not higher than 40 °C, and most preferably at a temperature
not higher
than 28 °C. This preference is not inconsistent with the need for
pressure-side fluid
resistance of the die-side lubricant as described above. Typical aqueous based
cleaners are either more acidic or more alkaline than most aqueous pressure-
side
fluids used in hydroforming. Furthermore, even if the cleaners are neutral,
they
usually contain other cleaning-promoting ingredients such as detersive
surfactants
-9-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
that are not present in typical pressure-side fluids for hydroforming.
The die-side lubricant is also preferably easy to separate from the
pressure-side fluid should the lubricant become contaminated by the pressure-
side
fluid. Accordingly, self segregation of the die-side lubricant into a separate
phase
that can be skimmed or drained off from a reservoir of pressure-side fluid is
highly
desirable.
Finally, the lubricant is preferably easy to apply to the surface to be
lubricated, without producing any hazard such as flammable, toxic, or noxious
fumes, without requiring any equipment more complicated than simple spray,
immersion, andlor roll coating, and without requiring any special drying
equipment.
For example, if a die-side lubricant that is a solid when emplaced ready for
use can
be applied from a latex and allowed to dry in the ambient air without
producing any
fire hazard or unpleasant odor, there is a substantial practical advantage and
therefore a preference for it over a solid die-side lubricant that must be
melted to be
applied and then quickly cooled to avoid having the melted die-side lubricant
run off
the substrate being hydroformed.
In another embodiment of the present invention, a process for
hydroforming a tube of a ductile solid material is provided. The process
comprises
the following steps:
(I) providing a pressure-side fluid and an openable die having an
interior surface of a shape to which it is desired to have the
hydroformed part of the outer surface of the tube of ductile
solid material conform after the tube has been hydroformed;
(II) forming over the outer surface of the tube of ductile solid
material a coating of a die-side lubricant suitable for use in a
process according to the invention as described above, so as
to form a coated ductile tube;
-10-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
(III) emplacing the coated ductile tube within at least a part of said
openable die and closing the die, so that a portion of the outer
surface of the ductile tube that is desired to be hydroformed
is within the closed openable die;
(IV) filling the interior of the tube of ductile solid with a volume
of said pressure-side fluid, so that said pressure-side fluid
exerts equal pressure on all parts of the internal surface of the
tube of ductile solid with which the pressure-side fluid is in
physical contact; and
(V) applying to said volume of pressure-side fluid filling said
interior of the ductile tube, while the ductile tube remains
emplaced within the closed openable die as recited in
operation (III) above, a sufficient pressure to cause at least a
portion of the outer surface of the coated ductile tube to
conform to the inner surface of the closed openable die.
Only a relatively thin layer of the die-side lubricant is needed for
satisfactory lubrication. More particularly, the average thickness of the die-
side
lubricant layer formed before hydroforming begins preferably is in the range
0.2 to
200 microns, more preferable in the range 1.0 to 100 microns, and most
preferably
about 15 microns. Uniformity of the die-side lubricant is not critical. The
films
may even be discontinuous ball-like lumps and aggregates evenly distributed
over
the surface of the part.
Preferred lubricants for use according to the invention can be readily
removed from surfaces of metal ductile tubes, after hydroforming is completed,
by
conventional alkaline cleaners.
Except for use of the characteristic lubricant for this invention as
described above, the process conditions for a hydroforming process according
to the
-11-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
invention are normally the same as those already in use in the art. A process
according to the invention is particularly advantageous in "high pressure"
hydroforming, in which the hydraulic pressure in step (V) of the process as
described above is at least 340 bars and independently is particularly
advantageous
in hydroforming cold rolled steel, but is suitable for hydroforming any other
ductile
solid as well. Hydroforming with these lubes is successful with hot-rolled
steel,
cold-rolled steel, and aluminum, both 5000 and 6000 series alloys.
The invention may be further appreciated by consideration of the
following examples and comparison examples. In all of the tests below, the
metal
substrate was type ADI~Q 95 hot-rolled steel, which is one of the most
commonly
hydroformed substrates.
TEST METHODS
CORNERFILL TEST
The cornerfill test is designed to test the properties required by a die-
side hyroforming lubricant in the expansion zone of a hydroforming process. In
these tests, the exterior surface of a welded cylindrical steel tube was
coated with
test die-side lubricant and then mounted in a die with a square cross-section
that was
within one millimeter of touching the exterior cross-section of the
cylindrical steel
tube at the center of all four walls of the square die, with no weld line at
or near one
of these centers of the die walls. The lubricant-coated exterior of the steel
tube was
then sprayed lightly with water before the die was closed. The interior of the
steel
tube was then filled with a volume of a water-based pressure side fluid, and
the
pressure in the tube was then increased until the tube burst. Sensors detected
the
pressure at various stages of expansion, the maximum pressure before the tube
burst, and the maximum expansion of the tube. The burst tube was then removed
from the die, and the tube burst location was noted. Then the dimensions of
the
burst tube were measured and the true thickness strain was calculated for
seven
-12-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
locations: the four corners and the centers of the three walls of the square
cross-
section into which the tube had expanded that did not include the original
welded
area. Three of the properties measured in this type of test are generally
considered
relevant to performance in actual hydroforming. A higher burst pressure is
better
than a lower one; a low standard deviation of the true thickness strain is
better than
a higher one; and a burst near the center of the tube is better than a burst
in any
other part of the tube.
TWIST COMPRESSION TEST
A twist compression test is designated to test the properties required
by a die-side hydroforming lubricant in transition zones near the edges of
expansion
zones in hydroforming. In these tests, an annular tool was rotated under
pressure
over a flat plate of steel on which the test lubricant had been emplaced. The
pressure applied on the lubricated plate in one set of tests was 10,000 psi
and in
another was 15,000 psi. These pressures are typical of commercial hydroforming
of hot rolled steel tubes. A plot of the coefficient of friction as a function
of time
was generated. The results are reported at 1, 2, and 3 revolutions. The test
was
first conducted dry for each lubricant and then twice after the lubricant had
been
sprayed lightly with water. Only the average of the latter two of these
measurements is reported below. The tests were also performed on lubricants
sprayed with Novacool 9034, a pressure-side fluid commercially available from
Henkel Corporation, Madison Heights, Michigan. The lower the coefficient of
friction in these tests, the better performance the lubricant usually gives in
the
transition zone.
SLIDING FRICTION TEST
The sliding friction test measures the properties of the die-side
lubricant that are important in the "end-feeding zone" of a hydroforming
process.
In this end-feeding zone, the tube being hydroformed does not substantially
expand
-13-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
or contract its eternal cross-section, although its walls may thin or thicken.
Instead,
part of the tube moves laterally along the die to allow for expansion in
another part
of the die. This end-feeding is very important in the production of some part
designs by hydroforming. The procedure used for this type of test for which
values
are reported here is described in American Society for Testing and Materials
("ASTM") Procedure 4173-82, using a compressive pressure between the sliding
workpieces of 69 bars ( 1000 psi). (This is officially an "obsolete" ASTM test
method, but it is still useful for measuring the coefficient of friction in
sliding
friction.) The lower the coefficient of friction in sliding friction, the
better is the
lubricant in the end-feeding zone.
Solid Film Lubricants
Examples 1-4 provides examples of the solid film lubricants of the
present invention.
Example 1
Component Weight %
carnuba wax aqueous89.5
emulsion, 22 % solids,
(Michelman Michem
Lube 160)
water 8.0
monoethanolamine 0.5
sodium benzoate 2.0 % .
Total 100
The monoethanolamine reduces the staining by the wax by the
slightly acidic carnuba wax by raising the pH. Finally, the sodium benzoate is
a
-14-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
corrosion inhibitor. The carnuba wax is characterized with a hardness of about
1
(ASTM-D-5), a particle size of about 0.15 microns, and a melting point of
about 85
°C.
Example 2
Component Weight %
microcrystalline 99.0
wax
emulsion, 42 % solids,
(Michelman Michem
Lube 124)
nonionic surfactant,1.0
(Air
Products Surfynol
440)
Total 100
, The microcrystalline wax is a mixture of two waxes of hardness 5
and 13 using ASTM D-5 and with melting points centered around 68 and 101
degrees C. Furthermore, the microcrystalline wax has a particle size of about
0.18
microns.
Example 3
Component Weight %
Fischer-Tropsch 99.9
wax
emulsion, 40 % solids,
(Michelman Emulsion
64540)
nonionic surfactant,0.1
(Air
Products Surfynol
420)
-15-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
I Total 100
The Fischer-Tropsch wax is characterized with a hardness of about
1 (ASTM-D-5), a particle size of about 0.6 microns, and a melting point of
about
98 °C.
Example 4
Component Weight %
Fischer-Tropsch 92.5
wax
emulsion, 40 % solids,
(Michelman Emulsion
98040M 1 )
nonionic surfactant,1.0
(Air
Products Surfynol
440)
neodecanoic acid 4.0
~ KOH, 45 % 2.5
Total 100.00
The neodecanoic acid functions as both a corrosion inhibitor and
defoamer. The Fischer-Tropsch wax is characterized as set forth above for
example
3.
The results of the twist compression measurements for the lubricants
in examples 1-3 are summarized in Tables 1 and 2.
Table 1. Twist Compression Results using 6061 T4 Aluminum at 10,000 psi
Lube Prewet initial COF Q COF Q COF Q
Fluid COF 1 rev 2 rev 3 rev
-16-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
example water 0.07 0.06 0.07 0.09
1
example 9034 0.01 0.03 0.03 0.04
1
example water 0.01 0.03 0.06 0.08
2
example 9034 0.01 0.03 0.07 0.10
2
Table 2. Twist Compression Results using Hot-Rolled Steel at 15,000 psi
Lube Prewet initial COF Q COF Q COF Q
Fluid COF 1 rev Z rev 3 rev
example water 0.01 0.02 0.04 0.06
1
example 9034 0.04 0.04 0.05 0.05
1
example water 0.01 0.03 0.03 0.04
2
example 9034 0.01 0.03 0.03 0.03
2
example3 water 0.01 0.02 0.03 0.04
example3 9034 0.01 0.02 0.03 0.04
The coefficient of friction (COF) was determined by the sliding
friction test for various wetted and unwetted waxes. The results are
summarized in
Table 3. Surprisingly, the COF is reduced when the waxes are wetted.
Table 3. Coefficient of friction for various waxes.
Wax COF (Neat) COF (wetted)
carnuba wax 0.30-0.20 0.20-0.10
montan wax 0.20-0.18 0.18-0.12
microcrystalline 0.12-0.10 < 0.10
wax
Fischer-Tropsch - < 0.10
wax
-17-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
Liauid Film Lubricants
Examples 5-8 provide examples of the liquid film compositions of the
present invention.
Example 5
Component Weight %
blown canola oil, 97.5
Z2
viscosity
ethoxylated castor 2.5
oil,
Chemax CO-5
Total 100.00
In view of the tackiness of blown canola oil, the ethoxylated castor
oil is water miscible and makes it easier to wash the composition in example
5. The
ethoxylated castor oil in provided in such an amount that the washability of
the
formulation improved but lubricity of the formulation is only minimally
degraded.
Small amounts of the ethoxylated castor oil actually improve lubricity.
Example 5
has a burst pressure of about 10,510 psi; a twist compression coefficient of
friction
at 10,000 psi of about 0.06; a twist compression coefficient of friction at
15,000 psi
of about 0.05; and a sliding coefficient of about 0.065.
Tables 4 and 5 summarize the twist compression results for the
composition described by example 5.
Table 4. Twist Compression Results using 6061 T4 Aluminum at 10,000 psi
Lube Prewet initial COF Qa COF Q COF ~
Fluid COF 1 rev 2 rev 3 rev
example water 0.06 0.27 0.29 0.28
5
-18-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
~ example 5 ~ 9034 ~ 0.10 ~ 0.24 ~ 0.32 ~ 0.35
Table 5. Twist Compression Results using Hot-Rolled Steel at 15,000 psi
Lube Prewet initial COF Q COF Q COF Q
Fluid COF 1 rev 2 rev 3 rev
example water 0.08 0.07 0.09 0.14
5
example 9034 0.09 0.07 0.08 0.07
5
Example 6
Component Weight %
canola oil 97.5
ethoxylated castor 2.5
oil,
Chemax CO-5
Total 100.00
Example 7
Component Weight %
blown herring oil, 95.0
ZS
viscosity
-19-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
ethoxylated castor 5.0
oil,
Chemax CO-5
Total 100.00
Example 8
Component Weight %
blown canola oil, 47.5
Z2
viscosity
naphthenic oil, 50.0
100 SUS
viscosity
ethoxylated castor 2.5
oil,
Chemax CO-5
Total 100.00
Example 8 has a burst pressure of about 10,510 psi; a twist
compression coefficient of friction at 10,000 psi of about 0.06; a twist
compression
coefficient of friction at 15,000 psi of about 0.05; and a sliding coefficient
of about
0.065
The coefficient of friction (COF) was determined for mixtures of
blown canola oil and various surfactant. The COF was measure both for neat
(unwetted) and wetted mixtures. Table 6 summarizes the results. The
coefficient
of friction is surprisingly reduced in each case when wetted. Chemal DA-6 is
the
surfactant ethoxylated decyl alcohol with 6 moles of ethoxylation for each
mole of
alcohol, Chemal DA-9 is the surfactant ethoxylated decyl alcohol with 9 moles
of
ethoxylation for each mole of alcohol, Chemal LA-4 is the surfactant
ethoxylated
-20-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
lauryl alcohol with 4 moles of ethoxylation for each mole of alcohol, Chemax
CO-5
is the surfactant ethoxylated castor glyceride with 5 moles of ethoxylation
for each
mole of castor glyceride; Chemax CO-16 is the surfactant ethoxylated castor
glyceride with 16 males of ethoxylation for each mole of castor glyceride; and
Chemax CO-80 is the surfactant ethoxylated castor glyceride with 80 moles of
ethoxylation for each mole of castor glyceride.
Table 6. COF for neat and wetted mixtures of blown canola oil and surfactant.
Lubricant COF at 2350 psi % reduction in COF
blown canola oil 0.040
+ 2.5 %
DA-6
blown canola oil 0.025 37.5
+ 2.5 %
DA-6
blown canola oil 0.032
+ 2.5 %
DA-9
blown canola oil 0.028 12.5
+ 2.5 %
DA-9
blown canola oil 0.024
+ 2.5 %
LA-4
blown canola oil 0.017 29
+ 2.5 %
LA-4
blown canola oil 0.037
+ 2.5 %
CO-5
blown canola oil 0.021 43
+ 2.5 % CO-
5
blown canola oil 0.035
+ 2.5 % CO-
16
blown canola oil 0.022 37
+ 2.5 % CO-
16
blown canola oil 0.036
+ 2.5 % CO-
80
blown canola oil 0.024 33
+ 2.5 % CO-
80
-21-
CA 02512682 2005-07-07
WO 2004/062836 PCT/US2003/041577
The COF was determined for neat (unwetted) and wetted mixtures of
blown canola oil and the surfactant Chemax CO-40. Table 7 summarizes the COF
for varying amounts of Chemax CO-40 in blown canola oil, Z2, viscosity. Chemax
is an ethoxylated caster glyceride with 40 moles of ethoxylation for each mole
of
caster glyceride. Again, the wetted mixtures have lower COF than the neat
mixture.
Table 7. COF for neat and wetted mixtures of blown canola oil and Chemax
CO-40.
Lubricant COF % reduction COF at % reduction
at in in
2900 COF 2900 psi COF
psi
blown canola 0.015 - - -
oil +
2.5 % CO-40
(neat)
blown canola 0.012 20 % - -
oil +
2.5 % CO-40
(wetted)
blown canola - - 0.034 -
oil +
2.5 % CO-40
(neat)
blown canola - - 0.023 32%
oil +
2.5 % CO-40
(wetted)
blown canola - - 0.042 -
oil +
5%CO-40 (neat)
blown canola - - 0.039 7%
oil +
5 % CO-40 (wetted)
While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and describe
all
possible forms of the invention. Rather, the words used in the specification
are
words of description rather than linutation, and it is understood that various
changes
may be made without departing from the spirit and scope of the invention.
-22-
