Note: Descriptions are shown in the official language in which they were submitted.
~554~
This invention relates to metal working lubricants and
more particularly to a metal working lubricant which can be used
in drawing and ironing type fabrication of sheet metal stock.
In the fabricating of metal into complex shapes such ~ -
as, for example, the drawing and ironing steps used in producing
a formed container or can from a sheet of, for example, aluminum
or steel, a number of different lubricants are usually involved.
Residual oils are present on most sheet surfaces from prior
rolling and fabricating opera~ions; an additional process lubri-
cant is used for the drawing operation; a third process lubricant
is used for the ironing operation; and yet another lubricant,
namely the mechanical or hydraulic lubricant associated with the
press equipment, may, at least in part, become inadvertently
mixed with the process lubricants. Normally these lubricants are
of different constituency although it is known to use the same
lubricant in both drawing and ironing operations although at
different concentrations.
It is known to mix carboxylic acids such as fatty acids
with mineral oils to produce lubricants. For example, both Moser
U.S. Patent No. 2,124,628 and Montgomery U.S. Patent No.
2,151,353 disclose the use of oleic acid with a mineral oil as a
lubricant. However, such lubricants were usually used as nea~
oils in the 1930's, that is, were not further diluted by disper-
sion or emulsification in an aqueous medium as is a common
practice today.
It is also known to disperse fatty acid esters and
soaps in mineral oil lubricants. However, such lubricants are
difficult to work with in that filters used to filter out im-
purities and foreign material (such as metal shavings or the
like~ are blinded by the soaps. Furthermore, such lubricants
having soaps ~erein are usually somewhat alkaline (pH of about 8
or ~) and subse~uent treatment of the form~d metal piece with
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~S54'73
acid cleaners to remove the lubricant therefrom tends to break
down ~he soap and thus the lubricant cannot be recycled or
reused.
It has also been found with many prior art lubricants
that the residual oils already contained on the metal stock are
not compatible therewith which further provides a contamination
type of effect. The same is true of the hydraulic and mechanical
oils used in the presses which, when inevitably some mixture
occurs, provide a contamination of the lubricant therefore making
it unreusable without reprocessin~.
Sawyer U.S. Patent No. 3,657,126, assigned to the
assignee of this invention, describes an emulsifiable lubricant
which comprises the combination of a dispersion of an aliphatic
carboxylic acid glycol ester in mineral oil with an emulsifying
agent to provide emulsification or dispersion of the neat oil in
an aqueous media. While this lubricant has been effective in
some metal working operations, it has been found that many of the
problems enumerated above still exist with the use of this oil
for drawing and ironing lubrication.
It is therefore an object of this invention to provide
a lubricant dispersible or emulsifiable in water which can be
used at some established concentration as both a drawing and -~
ironing lubricant, which can also be used (as a neat oil) as the
hydraulic and/or mechanical oil, and which will be compatible
~ with the residual oils usually contained on the metal stock as a , -
`- result of prior fabricating operations. It is a further object
of the invention to provide a lubricant which will be chemically
stable in the presence of further acid cleaning treatment to
remove the oils from the metal to thereby permit recycling of the
30 lubricant without loss due to contact with acid. These and ~
objects of the i~vention will be apparent from the description ~-
and accompanying flowsheet.
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The sole drawing of the invention is a flowsheet illustrating
the components of the lubricant of the invention.
This invention provides a metal working lubricant dispersible
in an aqueous media comprising: ~a) a fatty acid containing at least 12
carbon atoms including at least one carboxylic acid group; (b~ an aliphatic
carboxylic acid ester; ~c) at least one emulsification agent; and (d) mineral
oil.
These ingredients can be further dispersed in an aqueous media
which preferably comprises deionized water or soft water containing less
- 10 than about 250 ppm hardness. Preferably the amount of the ingredients which
will be referred to hereinafter as the neat oil comprise from 4 to 30 parts
per 100 parts of the neat oil water dispersion. For purposes o~ this des-
cription, the terms "emulsion" and "dispersion" will be considered to be the
same.
In accordance with the invention, the neat oil ingredients, in
parts by weight, preferably comprise about 2 to 8 parts carboxylic acid, 4 to
10 parts emulsifier, and 10 to 20 parts of the aliphatic carboxylic acid
ester, with the balance made up of mineral oil for a total of 100 parts.
The viscosity of the total mixture of neat oil in the preferred embodiment
should be at least about 250 to 450 Saybolt Seconds Universal (SSU) at 100F,
although a somewhat higher viscosity such as 500-550 SSU tat 100P) can be
used when operating at higher process equipment temperature. Depending upon
j the amount of the ingredients other than the mineral oil and their effect on
viscosity, the viscosity of the mineral oil will be .selected to provide this
final viscosity of the blend.
In aceordance with the invention, the earboxyllc acid useul in
the invention must possess good film strength or load bearing characteristics;
preferably should also be capable of dispersing generated metal fines, that
is, not have a tendency to agglomerate metal fines. It should be sufficiently
soluble to have a ~rue solubility at 70F, that is, it should not become
pasty or only part~ally soluble when cooled to about room
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IL~5~i473
~emperature. Carboxylic acids useful in the invention are monomeric straight
chain monocarboxylic and dicarboxylic acids. Generally, the carboxylic acids
useful in the invention have bhe formula:
CmH2m_n~2_r~cOoH)r wherein:
m equals an integer which is at least 11, preferably at least
13, not more than 34, and preferably not more than 17;
n is 0 or an even integer from 2 to 6;
r equals 1 or 2.
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~; Examples of higher molecular weight monocarboxylic acids fitting
within the above category include oleic acid, linoleic acid, s~earic acid,
linolenic acid, palmitic acid, myristic acid, and lauric acid, as well as ~ ~ -
isomers of any of the above acids and dimers thereof. When the dimer is used,
preferably the carboxylic acid groups are partially blocked or reacted to
provide a stoichiometry less than that of a dicarboxylic acid, preferably
approximating that of monocarboxylic acids t:o avoid the agglomerating ten-
dencies of polycarboxylic acids.
Preferably, the carboxylic acid contains at least 17 carbons in
addltion to the carboxylic acid group and most preferably the acid comprises
oleic acid.
The aliphatic carboxylic acid ester component of the lubricant
~, preferably comprises the esteri~ied product of monocarboxylic acids having
at least 4 carbon atoms with monoalcohols or polyhydroxy alcohols ~polyols)
including polyhydroxy polyether alcohols. Bxamples of the monocarboxylic
acids which may be used in the ester include butyric acid, caproic acid~
~-~ caprylic acid, capric acid, ~auric acid, myristic acid, and palmitic acid.
i Bxamples of such alcohols include methyl alcohol, ethyl alcohol, isopropyl
alcohol, ethylene glycol, propylene glycol, glycerol, diethylane glycol,
triethylene gly~ol~ dipropylene glycol and tripropylene glycol.
The acids which have been esteriied with
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lC~S59~'73
the alcohol may comprise only one acid or may be a mixture of
acids. A commercially available example of a mixture of such
acids is that sold under the trademark "Hallco Plasticizer 4141"
by the C. P. Hall Company which comprises a triethylene glycol
caprate-caprylate.
The emulsification or dispersion agent used in the
lubricant of the invention preferably comprises one or more non-
ionic and non-metallic emulsifiers which may be an ether or, pref
erably, an ester. Such emulsifying agents useful in the invention
include polyoxyalkalene oxide ethers or esters of, respectively, -
C12-C18 alcohols or acids; sorbitan fatty acid esters; and chemi-
cal or physical mixtures of such ethers and esters. Examples of
such compounds include pol~oxyalkalene oxide ethers such as poly-
oxyethylene lauryl ester; polyoxyalkalene oxide esters such as
polyoxyethylene stearate and polyoxyethylene oleate; sorbitan
esters such as sorbitan monolaurate, sorbitan mono oleate; or
mixed esters such as polyoxyethylene sorbitan mono oleate. In
accordance with the invention, physical comblnations of such ether
and ester emulsifiers may be used where there is insufficient
stirring or mechanical agitation to maintain the emulsion. For
; example, it has been found that 4 parts per 100 parts of an ether
; emulsifier is sufficient where agitation is used such as by stir-
ring or pump recirculation or the like. However, in other in-
stances where, for example, the sheet to be fabricated is lubri-
cated by being merely passed through a pan or trough, it has been
found that additional emulsifiers must be used, preferabl~ at
least a portion of which are ester based emulsifiers.
The balance of the neat oil comprises mineral oil. The
mineral oil is preferably at a viscosity of about 250 SSU to pro-
vide sufficient viscosity after dilution with the other ingredientsto provide a final viscosity of the neat oil of from 250 to 450
SSU, and prefera~ly from 350 to 400 SSU - although, as previously
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1(:! 55~3
mentioned, higher viscosities can be used when operating at higher
process equipment temperatures.
It should be recognized that minor amounts of other
additives such as corrosion inhibitors, bactericides, or the like
may be added where necessary or desired.
The following examples will serve to ~urther illus~rate
the invention.
Example 1
Five parts by weight oleic acid was blended with 15
parts by weight of triethylene glycol caprate-caprylate (trade- ;
marked "Hallco Plasticizer 41~1"), 3 parts by weight polyoxyethy~
lene lauryl ether (trademarked "Brij 30") and 77 parts by weight
of a mineral oil having a viscosity of about 1,000 SSU ~trademarked
"Circo X Heavy"). The resulting oil was diluted with water to
form a series of emulsions with ratios of 1 part neat oil to 3-9
parts water respectively (in parts by volume). The resulting
emulsions had pHs ranging from 5-6. In addition~ the neat oil was
used as the mechanical oil in the drawing press and the ironing
press used to conduct the experiments. A 3004-Hl9 aluminum alloy
metal containing residual rolling lubricants thereon was drawn and
ironed to form cans using the above dilutions of lubricant in ;
accordance with the invention. The resulting cans were examined
and found to be superior to cans produced under similar conditions
using conventional lubricants blended with waterO Furthermore,
the lubricant was found to actually "clean" the ironer equipment
and exit track work by dispersing the residual metallic debris in
the lubricant.
After drawing and ironing the stock, the drawn and
ironed cans were washed in water, then in a detergent with a pH
controlled to 1.6 with sulfuric acid, followed by subsequent water
washings and fin~lly drying. The residual lubricant on the drawn
and ironed cans ~as removed by these washings and recovered by a
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~55~7~
skimming operation. It was ound that the recovered lubricant had
not been broken down by the action of the acid. The filters used
in the circulation of the lubricant were examined following the
drawing o~eration to determine whether any soap formation had
occurred resulting in a blinding of the filters used to clean the
filter materials. The filter material was found to be in excel-
lent condition without any visible traces of blinding due to soap.
The same results were obtained using the above lubricant
on 3004-H19 aluminum alloy with numerous residual oil types and
amounts thereon.
Example 2
Following the procedures of Example 1, cans were drawn
and ironed using a lubricant similar to Example 1 axcept that lin-
oleic acid, isostearic acid and lauric acid were, respectively, sub-
stituted for the oleic acid. Similar results were obtained except
that slightly lower lubricant film strength properties resulted. ~ -
xample 3
To illustrate the use of a combination of emulsifiers,
the following neat oil lubricant was formulated:
5 parts oleic acid
15 parts triethylene glycol caprate-
caprylate (trademarked "Hallco
Plasticizer 4141")
4 parts polyoxyethylene lauryl ether
(trademarked "Brij 30"~
4 parts polyoxyethylene strearate
~-~ (trademarked "Myrj 45")
-~ 72 parts 1400 SSU Mineral oil
A portion of the blended lubricant, which had a viscosity
of 400 SSU, was emulsified using 1 part neat oil per 5 parts de-
ionized water. This portion was used as the metal lubricant in a
drawing press. ~ seond portion of the neat oil lubricant was emul-
sified in a 1:1~ neat oil to deionized water ratio and used as the
,:
rnetal lubricant in an ironing press.
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1C1 554~73
In both instances, it was found that the lubricant was
sufficiently stable to permit 24-hour (constant) operation
without replacement of the lubricant because of breakdown.
Periodic additions, of course, were made in each instance due to
depletion of the lubricant due to spillage and residues on the
drawn and ironed can. The lubricant was found to produce cans of
superior quality to those produced under similar conditions with
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conventional lubricants. Furthermore, the dispersion qualities
of the lubricant were found to be excellent.
Various modifications may be made in the invention
without departing from the spirit thereof, or the scope of the
claims, and, therefore, the exact form shown is to be taken as
illustrative only and not in a limiting sense, and it is desired
- that only such limitations shall be placed thereon as are imposed
by the prior art, or are specifically set orth in the appended
. ,,r~ claims.
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