U.S. patent application number 11/831896 was filed with the patent office on 2009-02-05 for metalworking fluid compositions and preparation thereof.
This patent application is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Emerson Castro, Allan G. Hee, Alex Munoz, Katrina Pass.
Application Number | 20090036338 11/831896 |
Document ID | / |
Family ID | 39789347 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090036338 |
Kind Code |
A1 |
Hee; Allan G. ; et
al. |
February 5, 2009 |
Metalworking Fluid Compositions and Preparation Thereof
Abstract
A metalworking fluid composition comprising an isomerized base
oil having consecutive numbers of carbon atoms and less than 10 wt
% naphthenic carbon by n-d-M is provided. The metalworking fluid
has reduced mist formation, low foaming tendency and excellent air
release properties.
Inventors: |
Hee; Allan G.; (Albany,
CA) ; Munoz; Alex; (Hercules, CA) ; Pass;
Katrina; (Richmond, CA) ; Castro; Emerson;
(Manteca, CA) |
Correspondence
Address: |
CHEVRON CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron U.S.A. Inc.
San Ramon
CA
|
Family ID: |
39789347 |
Appl. No.: |
11/831896 |
Filed: |
July 31, 2007 |
Current U.S.
Class: |
508/506 ;
508/110; 508/591 |
Current CPC
Class: |
C10N 2020/071 20200501;
C10M 107/02 20130101; C10M 2219/022 20130101; C10M 2219/024
20130101; C10N 2020/017 20200501; C10N 2020/069 20200501; C10N
2030/30 20200501; C10N 2030/18 20130101; C10N 2030/64 20200501;
C10M 2209/084 20130101; C10M 2205/173 20130101; C10N 2020/065
20200501; C10N 2030/74 20200501; C10N 2030/02 20130101; C10M
2219/046 20130101; C10N 2020/067 20200501; C10N 2030/06 20130101;
C10N 2040/22 20130101; C10N 2020/02 20130101; C10N 2030/08
20130101 |
Class at
Publication: |
508/506 ;
508/110; 508/591 |
International
Class: |
C10M 169/04 20060101
C10M169/04 |
Claims
1. A metalworking fluid, comprising: a lubricant base oil having
consecutive numbers of carbon atoms and less than 10 wt %
naphthenic carbon by n-d-M; and 0.10 to 10 wt. %. of at least an
additive selected from the group of a metalworking fluid additive
package; metal deactivators; corrosion inhibitors; antimicrobial;
anticorrosion; extreme pressure agents; antifriction; antirust
agents; polymeric substances; anti inflammatory agents;
bactericides; antiseptics; antioxidants; chelating agents such as
edetic acid salts, and the like; pH regulators; antiwear agents;
and mixtures thereof wherein the metalworking fluid has an air
release by ASTM D 3427-03 of less than 0.6 minutes at 50.degree.
C., and a sequence II foam tendency by ASTM D 892-03 of less than
50 mL.
2. The metalworking fluid of claim 1, wherein the air release at
50.degree. C. is less than 0.5 minutes.
3. The metalworking fluid of claim 1, wherein the sequence II foam
tendency by ASTM D 892-03 is less than 40 mL.
4. The metalworking fluid of claim 1, wherein the sequence II foam
tendency by ASTM D 892-03 is less than 20 mL.
5. The metalworking fluid of claim 1, wherein the metalworking
fluid has a biodegradability of at least 30% as measured according
to OECD 301D.
6. The metalworking fluid of claim 1, wherein the metalworking
fluid additionally has a sequence 1 foam tendency by ASTM D 892-03
of less than 50 mL.
7. The metalworking fluid of claim 1, wherein the metalworking
fluid has a number of minutes to 3 mL emulsion at 54.degree. C. by
ASTM D 1401-02 of less than 30.
8. The metalworking fluid of claim 1, wherein the lubricant base
oil is a Fischer-Tropsch derived base oil made from a waxy
feed.
9. The metalworking fluid of claim 9, wherein the Fischer-Tropsch
derived base oil has a kinematic viscosity at 100.degree. C.
between 2 mm.sup.2/s and 6 mm.sup.2/s; a kinematic viscosity at
40.degree. C. between 7 mm.sup.2/s and 20 mm.sup.2/s; CCS viscosity
of less than 2300 mPas at -35.degree. C.; a pour point in the range
of -20 and -40.degree. C.; a molecular weight of 300-500; a density
in the range of 0.800 to 0.820; paraffinic carbon in the range of
93-97%; naphthenic carbon in the range of 3-7%; Oxidator BN of 30
to 60 hours; and Noack volatility in wt. % of 8 to 20 as measured
by ASTM D5800-05 Procedure B.
10. The metalworking fluid of claim 1, wherein the lubricant base
oil comprises an isomerized based oil and 5 to 20 wt. % of at least
one of mineral oils, synthetic hydrocarbon oils or synthetic ester
oils and mixtures thereof.
11. The metalworking fluid of claim 1, wherein the lubricant base
oil has an average molecular weight between 600 and 1100, and an
average degree of branching in the molecules between 6.5 and 10
alkyl branches per 100 carbon atoms.
12. The metalworking fluid of claim 1, wherein the lubricant base
oil has a wt % Noack volatility between 0 and 100.
13. The metalworking fluid of claim 1, wherein the lubricant base
oil has an auto-ignition temperature (AIT) greater than an amount
defined by: 1.6.times.(Kinematic Viscosity at 40.degree. C., in
mm.sup.2/s)+300.
14. The metalworking fluid of claim 1, wherein the lubricant base
oil has an auto-ignition temperature (AIT) greater than 329.degree.
C.
15. The metalworking fluid of claim 1, wherein the lubricant base
oil has a viscosity index greater than 28.times.Ln (Kinematic
Viscosity at 100.degree. C., in mm.sup.2/s)+300.
16. The metalworking fluid of claim 1, wherein the lubricant base
oil has a ratio of weight percent molecules with
monocycloparaffinic functionality to weight percent molecules with
multicycloparaffinic functionality of greater than 15.
17. The metalworking fluid of claim 1, wherein the lubricant base
oil has a total weight percent of molecules with cycloparaffinic
functionality of greater than 10, and a ratio of weight percent
molecules with monocycloparaffinic functionality to weight percent
molecules with multicycloparaffinic functionality of greater than
15.
18. The metalworking fluid of claim 1, wherein the lubricant base
oil has a Kinematic Viscosity at 100.degree. C. of >1.808
mm.sup.2/s and a Noack volatility less than an amount calculated
by: 1.286+20 (Kinematic Viscosity at 100.degree. C.).sup.-1.5+551.8
Ln (Kinematic Viscosity at 100.degree. C.).
19. The metalworking fluid of claim 1, wherein the lubricant base
oil comprises greater than 3 weight % molecules with
cycloparaffinic functionality and less than 0.30 weight percent
aromatics.
20. The metalworking fluid of claim 1, wherein the lubricant base
oil greater than 10 wt. % and less than 70 wt. % total molecules
with cycloparaffinic functionality
21. The metalworking fluid of claim 1, wherein the lubricant base
oil has a traction coefficient of less than 0.023 when measured at
a kinematic viscosity of 15 mm.sup.2/s and at a slide to roll ratio
of 40%.
Description
TECHNICAL FIELD
[0001] The invention relates generally to metalworking compositions
exhibiting improved anti-mist properties, having a low foaming
tendency and excellent air release properties.
BACKGROUND
[0002] Industrial metal cutting operations, such as the cutting of
silicon wafers by the semiconductor industry, utilize machining or
metalworking fluids to aid in or enhance the cutting process.
Metalworking fluids can be used as cutting oils, rolling oils,
drawing oils, pressing oils, forging oils, abrasive working oils
for aluminium disks, abrasive oils for silicon wafers and coolants.
In high-speed machining operations involving require rapid fluid
application and recirculation, foam and air entrainment are
sometimes experienced with undesirable results. Foaming is
undesirable because it may reduce cooling at the workpiece-tool or
chip-tool contact zones and cause containment transport and control
problems. Various methods or strategies have been implemented to
eliminate or reduce foaming, including the addition of foam control
agent(s) when manufacturing the product or while the fluid is
in-service. The use of certain foam control agent(s), such as such
as silicon-based foam inhibitors, could leave a residue on machined
parts and make subsequent painting of the parts difficult.
Additionally, some foam control agent(s)may worsen a metalworking
fluid's air release properties.
[0003] A fluid's air release properties can also be critical to its
in-service performance, especially for high-speed operations. In
some cases, using a fluid with poor air release properties can lead
to air entrainment issues and cavitation of machine parts.
[0004] Besides foaming and air release, another common in-service
problem associated with metalworking fluids is fog or mist
generation. During the cutting process, small amounts of cutting
oil tend to escape into the surrounding air as micro-sized droplets
known as mist. Workers in the vicinity are exposed to the mist and,
unless a protective breathing apparatus is worn, a portion of the
mist may be drawn into the workers' lungs. Although metal cutting
fluids in the prior art are essential for machining, they are
currently being examined with increased scrutiny because of
possible hazards associated with worker exposure.
[0005] Various additives have been tried in the prior art to reduce
the formation of mist, including the use of minor amounts of at
least one of polyisobutene, poly-n-butene and mixtures thereof,
having a viscosity average molecular weight ranging from 0.3 to 10
million. Rhamsan gum, hydrophobic and hydrophilic monomers, styrene
or hydrocarbyl-substituted styrene hydrophobic monomers and
hydrophilic monomers are amongst other additives suggested for use
to reduce the mist formation. Some metal cutting fluids in the
prior art with the use of various additives pose environmental
problems associated with their disposal. There is now universal
agreement on the need for safer more environmentally friendly
metalworking fluids.
[0006] Recent reforming processes have formed a new class of oil,
e,g, Fischer Tropsch base oil (FTBO), wherein the oil, fraction, or
feed originates from or is produced at some stage by a
Fischer-Tropsch process. The feedstock for a Fischer-Tropsch
process may come from a wide variety of hydrocarbonaceous
resources, including biomass, natural gas, coal, shale oil,
petroleum, municipal waste, derivatives of these, and combinations
thereof. Crude product prepared from the Fischer-Tropsch process
can be refined into products such as diesel oil, naphtha, wax, and
other liquid petroleum or specialty products. In a number of patent
publications and applications, i.e., US 2006/0289337,
US2006/0201851, US2006/0016721, US2006/0016724, US2006/0076267,
US2006/020185, US2006/013210, US2005/0241990, US2005/0077208,
US2005/0139513, US2005/0139514, US2005/0133409, US2005/0133407,
US2005/0261147, US2005/0261146, US2005/0261145, US2004/0159582,
US7018525, US7083713, U.S. application Ser. Nos. 11/400570,
11/535165 and 11/613936, which are incorporated herein by
reference, an isomerized base oil is produced from a process in
which the feed is a waxy feed recovered from a Fischer-Tropsch
synthesis. The process comprises a complete or partial
hydroisomerization dewaxing step, using a dual-functional catalyst
or a catalyst that can isomerize paraffins selectively.
Hydroisomerization dewaxing is achieved by contacting the waxy feed
with a hydroisomerization catalyst in an isomerization zone under
hydroisomerizing conditions.
[0007] There is a need for an improved metalworking fluid with
reduced mist and foam formation and excellent air release
properties as compared to the compositions of the prior art.
Additionally, there is a need for an environmentally friendly
metalworking fluid.
SUMMARY OF THE INVENTION
[0008] In one embodiment, there is provided a metalworking fluid
comprising a lubricant base oil having consecutive numbers of
carbon atoms and less than 10 wt % naphthenic carbon by n-d-M; and
0.10 to 10 wt. %. of at least an additive selected from the group
of a metalworking fluid additive package; metal deactivators;
corrosion inhibitors; antimicrobial; anticorrosion; extreme
pressure agents; antifriction; antirust agents; polymeric
substances; anti inflammatory agents; bactericides; antiseptics;
antioxidants; chelating agents such as edetic acid salts, and the
like; pH regulators; antiwear agents; and mixtures thereof, and
wherein the metalworking fluid has an air release by ASTM D 3427-03
of less than 0.6 minutes at 50.degree. C., and a sequence II foam
tendency by ASTM D 892-03 of less than 50 mL.
[0009] In another aspect, there is provided a method to improve the
foam formation and air release properties of a metalworking fluid,
the method comprising blending a composition comprising a lubricant
base oil having consecutive numbers of carbon atoms and less than
10 wt % naphthenic carbon by n-d-M; and 0.10 to 10 wt. %. of at
least an additive selected from the group of a metalworking fluid
additive package; metal deactivators; corrosion inhibitors;
antimicrobial; anticorrosion; extreme pressure agents;
antifriction; antirust agents; polymeric substances; anti
inflammatory agents; bactericides; antiseptics; antioxidants;
chelating agents such as edetic acid salts, and the like; pH
regulators; antiwear agents; and mixtures thereof.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIGS. 1-3 are graphs illustrating the mist accumulation
rates of Examples 7-13 in an aerosol mist formation test.
DETAILED DESCRIPTION
[0011] The following terms will be used throughout the
specification and will have the following meanings unless otherwise
indicated.
[0012] As used herein, the term "metalworking fluid" may be used
interchangeably with "metalworking composition," "metal removal
fluid," "cutting fluid," "machining fluid," referring to a
composition that can be used in industrial metal cutting, metal
grinding operations or in the semiconductor industry wherein the
shape of the final object, e.g., silicon wafer or machine part, is
obtained by with or without the progressive removal of metal or
silicon. Metalworking fluids amongst other functions, are used to
cool and to lubricate.
[0013] "Fischer-Tropsch derived" means that the product, fraction,
or feed originates from or is produced at some stage by a
Fischer-Tropsch process. As used herein, "Fischer-Tropsch base oil"
may be used interchangeably with "FT base oil," "FTBO," "GTL base
oil" (GTL: gas-to-liquid), or "Fischer-Tropsch derived base
oil."
[0014] As used herein, "isomerized base oil" refers to a base oil
made by isomerization of a waxy feed.
[0015] As used herein, a "waxy feed" comprises at least 40 wt %
n-paraffins. In one embodiment, the waxy feed comprises greater
than 50 wt % n-paraffins. In another embodiment, greater than 75 wt
% n-paraffins. In one embodiment, the waxy feed also has very low
levels of nitrogen and sulphur, e.g., less than 25 ppm total
combined nitrogen and sulfur, or in other embodiments less than 20
ppm. Examples of waxy feeds include slack waxes, deoiled slack
waxes, refined foots oils, waxy lubricant raffinates, n-paraffin
waxes, NAO waxes, waxes produced in chemical plant processes,
deoiled petroleum derived waxes, microcrystalline waxes,
Fischer-Tropsch waxes, and mixtures thereof In one embodiment, the
waxy feeds have a pour point of greater than 50.degree. C. In
another embodiment, greater than 60.degree. C.
[0016] "Kinematic viscosity" is a measurement in mm.sup.2/s of the
resistance to flow of a fluid under gravity, determined by ASTM
D445-06.
[0017] "Viscosity index" (VI) is an empirical, unit-less number
indicating the effect of temperature change on the kinematic
viscosity of the oil. The higher the VI of an oil, the lower its
tendency to change viscosity with temperature. Viscosity index is
measured according to ASTM D 2270-04.
[0018] Cold-cranking simulator apparent viscosity (CCS VIS) is a
measurement in millipascal seconds, mPas to measure the viscometric
properties of lubricating base oils under low temperature and high
shear. CCS VIS is determined by ASTM D 5293-04.
[0019] The boiling range distribution of base oil, by wt %, is
determined by simulated distillation (SIMDIS) according to ASTM D
6352-04, "Boiling Range Distribution of Petroleum Distillates in
Boiling Range from 174 to 700.degree. C. by Gas
Chromatography."
[0020] "Noack volatility" is defined as the mass of oil, expressed
in weight %, which is lost when the oil is heated at 250.degree. C.
with a constant flow of air drawn through it for 60 min., measured
according to ASTM D5800-05, Procedure B.
[0021] Brookfield viscosity is used to determine the internal
fluid-friction of a lubricant during cold temperature operation,
which can be measured by ASTM D 2983-04.
[0022] "Pour point" is a measurement of the temperature at which a
sample of base oil will begin to flow under certain carefully
controlled conditions, which can be determined as described in ASTM
D 5950-02.
[0023] "Auto ignition temperature" is the temperature at which a
fluid will ignite spontaneously in contact with air, which can be
determined according to ASTM 659-78.
[0024] "Ln" refers to natural logarithm with base "e."
[0025] "Traction coefficient" is an indicator of intrinsic
lubricant properties, expressed as the dimensionless ratio of the
friction force F and the normal force N, where friction is the
mechanical force which resists movement or hinders movement between
sliding or rolling surfaces. Traction coefficient can be measured
with an MTM Traction Measurement System from PCS Instruments, Ltd.
, configured with a polished 19 mm diameter ball (SAE AISI 52100
steel) angled at 220 to a flat 46 mm diameter polished disk (SAE
AISI 52100 steel). The steel ball and disk are independently
measured at an average rolling speed of 3 meters per second, a
slide to roll ratio of 40 percent, and a load of 20 Newtons. The
roll ratio is defined as the difference in sliding speed between
the ball and disk divided by the mean speed of the ball and disk,
i.e. roll ratio=(Speed1--Speed2)/((Speed1+Speed2)-/2).
[0026] As used herein, "consecutive numbers of carbon atoms" means
that the base oil has a distribution of hydrocarbon molecules over
a range of carbon numbers, with every number of carbon numbers
in-between. For example, the base oil may have hydrocarbon
molecules ranging from C22 to C36 or from C30 to C60 with every
carbon number in-between. The hydrocarbon molecules of the base oil
differ from each other by consecutive numbers of carbon atoms, as a
consequence of the waxy feed also having consecutive numbers of
carbon atoms. For example, in the Fischer-Tropsch hydrocarbon
synthesis reaction, the source of carbon atoms is CO and the
hydrocarbon molecules are built up one carbon atom at a time.
Petroleum-derived waxy feeds have consecutive numbers of carbon
atoms. In contrast to an oil based on poly-alpha-olefin ("PAO"),
the molecules of an isomerized base oil have a more linear
structure, comprising a relatively long backbone with short
branches. The classic textbook description of a PAO is a
star-shaped molecule, and in particular tridecane, which is
illustrated as three decane molecules attached at a central point.
While a star-shaped molecule is theoretical, nevertheless PAO
molecules have fewer and longer branches that the hydrocarbon
molecules that make up the isomerized base oil disclosed
herein.
[0027] "Molecules with cycloparaffinic functionality" mean any
molecule that is, or contains as one or more substituents, a
monocyclic or a fused multicyclic saturated hydrocarbon group.
[0028] "Molecules with monocycloparaffinic functionality" mean any
molecule that is a monocyclic saturated hydrocarbon group of three
to seven ring carbons or any molecule that is substituted with a
single monocyclic saturated hydrocarbon group of three to seven
ring carbons.
[0029] "Molecules with multicycloparaffinic functionality" mean any
molecule that is a fused multicyclic saturated hydrocarbon ring
group of two or more fused rings, any molecule that is substituted
with one or more fused multicyclic saturated hydrocarbon ring
groups of two or more fused rings, or any molecule that is
substituted with more than one monocyclic saturated hydrocarbon
group of three to seven ring carbons.
[0030] Molecules with cycloparaffinic functionality, molecules with
monocycloparaffinic functionality, and molecules with
multicycloparaffinic functionality are reported as weight percent
and are determined by a combination of Field Ionization Mass
Spectroscopy (FIMS), HPLC-UV for aromatics, and Proton NMR for
olefins, further fully described herein.
[0031] Oxidator BN measures the response of a lubricating oil in a
simulated application. High values, or long times to adsorb one
liter of oxygen, indicate good stability. Oxidator BN can be
measured via a Dornte-type oxygen absorption apparatus (R. W.
Dornte "Oxidation of White Oils," Industrial and Engineering
Chemistry, Vol. 28, page 26, 1936), under 1 atmosphere of pure
oxygen at 340.degree. F., time to absorb 1000 mL of O.sub.2 by 100
g. of oil is reported. In the Oxidator BN test, 0.8 mL of catalyst
is used per 100 grams of oil. The catalyst is a mixture of soluble
metal-naphthenates simulating the average metal analysis of used
crankcase oil. The additive package is 80 millimoles of zinc
bispolypropylenephenyldithiophosphate per 100 grams of oil.
[0032] Molecular characterizations can be performed by methods
known in the art, including Field Ionization Mass Spectroscopy
(FIMS) and n-d-M analysis (ASTM D 3238-95 (Re-approved 2005)). In
FIMS, the base oil is characterized as alkanes and molecules with
different numbers of unsaturations. The molecules with different
numbers of unsaturations may be comprised of cycloparaffins,
olefins, and aromatics. If aromatics are present in significant
amount, they would be identified as 4-unsaturations. When olefins
are present in significant amounts, they would be identified as
1-unsaturations. The total of the 1-unsaturations, 2-unsaturations,
3-unsaturations, 4-unsaturations, 5-unsaturations, and
6-unsaturations from the FIMS analysis, minus the wt % olefins by
proton NMR, and minus the wt % aromatics by HPLC-UV is the total
weight percent of molecules with cycloparaffinic functionality. If
the aromatics content was not measured, it was assumed to be less
than 0.1 wt % and not included in the calculation for total weight
percent of molecules with cycloparaffinic functionality. The total
weight percent of molecules with cycloparaffinic functionality is
the sum of the weight percent of molecules with monocyclopraffinic
functionality and the weight percent of molecules with
multicycloparaffinic functionality.
[0033] Molecular weights are determined by ASTM D2503-92(Reapproved
2002). The method uses thermoelectric measurement of vapour
pressure (VPO). In circumstances where there is insufficient sample
volume, an alternative method of ASTM D2502-04 may be used; and
where this has been used it is indicated.
[0034] Density is determined by ASTM D4052-96 (Reapproved 2002).
The sample is introduced into an oscillating sample tube and the
change in oscillating frequency caused by the change in the mass of
the tube is used in conjunction with calibration data to determine
the density of the sample.
[0035] Weight percent olefins can be determined by proton-NMR
according to the steps specified herein. In most tests, the olefins
are conventional olefins, i.e. a distributed mixture of those
olefin types having hydrogens attached to the double bond carbons
such as: alpha, vinylidene, cis, trans, and tri-substituted, with a
detectable allylic to olefin integral ratio between 1 and 2.5. When
this ratio exceeds 3, it indicates a higher percentage of tri or
tetra substituted olefins being present, thus other assumptions
known in the analytical art can be made to calculate the number of
double bonds in the sample. The steps are as follows: A) Prepare a
solution of 5-10% of the test hydrocarbon in deuterochloroform. B)
Acquire a normal proton spectrum of at least 12 ppm spectral width
and accurately reference the chemical shift (ppm) axis, with the
instrument having sufficient gain range to acquire a signal without
overloading the receiver/ADC, e.g., when a 30 degree pulse is
applied, the instrument having a minimum signal digitization
dynamic range of 65,000. In one embodiment, the instrument has a
dynamic range of at least 260,000. C) Measure the integral
intensities between: 6.0-4.5 ppm (olefin); 2.2-1.9 ppm (allylic);
and 1.9-0.5 ppm (saturate). D) Using the molecular weight of the
test substance determined by ASTM D 2503-92 (Reapproved 2002),
calculate: 1. The average molecular formula of the saturated
hydrocarbons; 2. The average molecular formula of the olefins; 3.
The total integral intensity (=sum of all integral intensities); 4.
The integral intensity per sample hydrogen (=total integral/number
of hydrogens in formula); 5. The number of olefin hydrogens
(=olefin integral/integral per hydrogen); 6. The number of double
bonds (=olefin hydrogen times hydrogens in olefin formula/2); and
7. The wt % olefins by proton NMR=100 times the number of double
bonds times the number of hydrogens in a typical olefin molecule
divided by the number of hydrogens in a typical test substance
molecule. In this test, the wt % olefins by proton NMR calculation
procedure, D, works particularly well when the percent olefins
result is low, less than 15 wt %.
[0036] Weight percent aromatics in one embodiment can be measured
by HPLC-UV. In one embodiment, the test is conducted using a
Hewlett Packard 1050 Series Quaternary Gradient High Performance
Liquid Chromatography (HPLC) system, coupled with a HP 1050
Diode-Array UV-Vis detector interfaced to an HP Chem-station.
Identification of the individual aromatic classes in the highly
saturated base oil can be made on the basis of the UV spectral
pattern and the elution time. The amino column used for this
analysis differentiates aromatic molecules largely on the basis of
their ring-number (or double-bond number). Thus, the single ring
aromatic containing molecules elute first, followed by the
polycyclic aromatics in order of increasing double bond number per
molecule. For aromatics with similar double bond character, those
with only alkyl substitution on the ring elute sooner than those
with naphthenic substitution. Unequivocal identification of the
various base oil aromatic hydrocarbons from their UV absorbance
spectra can be accomplished recognizing that their peak electronic
transitions are all red-shifted relative to the pure model compound
analogs to a degree dependent on the amount of alkyl and naphthenic
substitution on the ring system. Quantification of the eluting
aromatic compounds can be made by integrating chromatograms made
from wavelengths optimized for each general class of compounds over
the appropriate retention time window for that aromatic. Retention
time window limits for each aromatic class can be determined by
manually evaluating the individual absorbance spectra of eluting
compounds at different times and assigning them to the appropriate
aromatic class based on their qualitative similarity to model
compound absorption spectra.
[0037] HPLC-UV Calibration. In one embodiment, HPLC-UV can be used
for identifying classes of aromatic compounds even at very low
levels, e.g., multi-ring aromatics typically absorb 10 to 200 times
more strongly than single-ring aromatics. Alkyl-substitution
affects absorption by 20%. Integration limits for the co-eluting
1-ring and 2-ring aromatics at 272 nm can be made by the
perpendicular drop method. Wavelength dependent response factors
for each general aromatic class can be first determined by
constructing Beer's Law plots from pure model compound mixtures
based on the nearest spectral peak absorbances to the substituted
aromatic analogs. Weight percent concentrations of aromatics can be
calculated by assuming that the average molecular weight for each
aromatic class was approximately equal to the average molecular
weight for the whole base oil sample.
[0038] NMR analysis. In one embodiment, the weight percent of all
molecules with at least one aromatic function in the purified
mono-aromatic standard can be confirmed via long-duration carbon 13
NMR analysis. The NMR results can be translated from % aromatic
carbon to % aromatic molecules (to be consistent with HPLC-UV and D
2007) knowing that 95-99% of the aromatics in highly saturated base
oils are single-ring aromatics. In another test to accurately
measure low levels of all molecules with at least one aromatic
function by NMR, the standard D 5292-99 (Reapproved 2004) method
can be modified to give a minimum carbon sensitivity of 500:1 (by
ASTM standard practice E 386) with a 15-hour duration run on a
400-500 MHz NMR with a 10-12 mm Nalorac probe. Acorn PC integration
software can be used to define the shape of the baseline and
consistently integrate.
[0039] Extent of branching refers to the number of alkyl branches
in hydrocarbons. Branching and branching position can be determined
using carbon-13 (.sup.13C) NMR according to the following nine-step
process: 1) Identify the CH branch centers and the CH.sub.3 branch
termination points using the DEPT Pulse sequence (Doddrell, D. T.;
D. T. Pegg; M. R. Bendall, Journal of Magnetic Resonance 1982, 48,
323ff.). 2) Verify the absence of carbons initiating multiple
branches (quaternary carbons) using the APT pulse sequence (Patt,
S. L.; J. N. Shoolery, Journal of Magnetic Resonance 1982, 46,
535ff.). 3) Assign the various branch carbon resonances to specific
branch positions and lengths using tabulated and calculated values
known in the art (Lindeman, L. P., Journal of Qualitative
Analytical Chemistry 43, 1971 1245ff; Netzel, D. A., et. al., Fuel,
60, 1981, 307ff). 4) Estimate relative branching density at
different carbon positions by comparing the integrated intensity of
the specific carbon of the methyl/alkyl group to the intensity of a
single carbon (which is equal to total integral/number of carbons
per molecule in the mixture). For the 2-methyl branch, where both
the terminal and the branch methyl occur at the same resonance
position, the intensity is divided by two before estimating the
branching density. If the 4-methyl branch fraction is calculated
and tabulated, its contribution to the 4+methyls is subtracted to
avoid double counting. 5) Calculate the average carbon number. The
average carbon number is determined by dividing the molecular
weight of the sample by 14 (the formula weight of CH.sub.2). 6) The
number of branches per molecule is the sum of the branches found in
step 4. 7) The number of alkyl branches per 100 carbon atoms is
calculated from the number of branches per molecule (step 6) times
100/average carbon number. 8) Estimate Branching Index (BI) by
.sup.1H NMR Analysis, which is presented as percentage of methyl
hydrogen (chemical shift range 0.6-1.05 ppm) among total hydrogen
as estimated by NMR in the liquid hydrocarbon composition. 9)
Estimate Branching proximity (BP) by .sup.13C NMR, which is
presented as percentage of recurring methylene carbons--which are
four or more carbons away from the end group or a branch
(represented by a NMR signal at 29.9 ppm) among total carbons as
estimated by NMR in the liquid hydrocarbon composition. The
measurements can be performed using any Fourier Transform NMR
spectrometer, e.g., one having a magnet of 7.0 T or greater. After
verification by Mass Spectrometry, UV or an NMR survey that
aromatic carbons are absent, the spectral width for the .sup.13C
NMR studies can be limited to the saturated carbon region, 0-80 ppm
vs. TMS (tetramethylsilane). Solutions of 25-50 wt. % in
chloroform-d1 are excited by 30.degree. pulses followed by a 1.3
seconds (sec.) acquisition time. In order to minimize non-uniform
intensity data, the broadband proton inverse-gated decoupling is
used during a 6 sec. delay prior to the excitation pulse and on
during acquisition. Samples are doped with 0.03 to 0.05 M Cr
(acac).sub.3 (tris (acetylacetonato)-chromium (III)) as a
relaxation agent to ensure full intensities are observed. The DEPT
and APT sequences can be carried out according to literature
descriptions with minor deviations described in the Varian or
Bruker operating manuals. DEPT is Distortionless Enhancement by
Polarization Transfer. The DEPT 45 sequence gives a signal all
carbons bonded to protons. DEPT 90 shows CH carbons only. DEPT 135
shows CH and CH.sub.3 up and CH.sub.2180 degrees out of phase
(down). APT is attached proton test, known in the art. It allows
all carbons to be seen, but if CH and CH.sub.3 are up, then
quaternaries and CH.sub.2 are down. The branching properties of the
sample can be determined by .sup.13C NMR using the assumption in
the calculations that the entire sample was iso-paraffinic. The
content of unsaturates may be measured using Field Ionization Mass
Spectroscopy (FIMS).
[0040] In one embodiment, the metalworking fluid comprises a number
of components, including optional additives, in a matrix of base
oil.
[0041] Base Oil Matrix Component: In one embodiment, the base oil
or blends thereof forming the matrix comprises at least an
isomerized base oil which the product itself, its fraction, or feed
originates from or is produced at some stage by isomerization of a
waxy feed from a Fischer-Tropsch process ("Fischer-Tropsch derived
base oils"). In another embodiment, the base oil comprises at least
an isomerized base oil made from a substantially paraffinic wax
feed ("waxy feed"). In a third embodiment, the base oil consists
essentially of at least an isomerized base oil.
[0042] Fischer-Tropsch derived base oils are disclosed in a number
of patent publications, including for example U.S. Pat. Nos.
6,080,301, 6,090,989, and 6,165,949, and US Patent Publication No.
US2004/0079678A1, US20050133409, US20060289337. The Fischer-Tropsch
process is a catalyzed chemical reaction in which carbon monoxide
and hydrogen are converted into liquid hydrocarbons of various
forms including a light reaction product and a waxy reaction
product, with both being substantially paraffinic.
[0043] In one embodiment the isomerized base oil has consecutive
numbers of carbon atoms and has less than 10 wt % naphthenic carbon
by n-d-M. In yet another embodiment the isomerized base oil made
from a waxy feed has a kinematic viscosity at 100.degree. C.
between 1.5 and 3.5 mm.sup.2/s.
[0044] In one embodiment, the isomerized base oil is made by a
process in which the hydroisomerization dewaxing is performed at
conditions sufficient for the base oil to have: a) a weight percent
of all molecules with at least one aromatic functionality less than
0.30; b) a weight percent of all molecules with at least one
cycloparaffinic functionality greater than 10; c) a ratio of weight
percent molecules with monocycloparaffinic functionality to weight
percent molecules with multicycloparaffinic functionality greater
than 20 and d) a viscosity index greater than 28.times.Ln
(Kinematic viscosity at 100.degree. C.)+80.
[0045] In another embodiment, the isomerized base oil is made from
a process in which the highly paraffinic wax is hydroisomerized
using a shape selective intermediate pore size molecular sieve
comprising a noble metal hydrogenation component, and under
conditions of 600-750.degree. F. (315-399.degree. C.) In the
process, the conditions for hydroisomerization are controlled such
that the conversion of the compounds boiling above 700.degree. F.
(371.degree. C.) in the wax feed to compounds boiling below
700.degree. F. (371.degree. C.) is maintained between 10 wt % and
50 wt %. A resulting isomerized base oil has a kinematic viscosity
of between 1.0 and 3.5 mm.sup.2/s at 100.degree. C. and aNoack
volatility of less than 50 weight %. The base oil comprises greater
than 3 weight % molecules with cycloparaffinic functionality and
less than 0.30 weight percent aromatics.
[0046] In one embodiment the isomerized base oil has a Noack
volatility less than an amount calculated by the following
equation: 1000.times.(Kinematic Viscosity at 100.degree.
C.).sup.-2.7. In another embodiment, the isomerized base oil has a
Noack volatility less than an amount calculated by the following
equation: 900.times.(Kinematic Vicosity at 100.degree.
C.).sup.-2.8. In a third embodiment, the isomerized base oil has a
Kinematic Vicosity at 100.degree. C. of >1.808 mm.sup.2/s and a
Noack volatility less than an amount calculated by the following
equation: 1.286+20 (kv100).sup.-1.5+551.8 e.sup.-kv100, where kv100
is the kinematic viscosity at 100.degree. C. In a fourth
embodiment, the isomerized base oil has a kinematic viscosity at
100.degree. C. of less than 4.0 mm.sup.2/s, and a wt % Noack
volatility between 0 and 100. In a fifth embodiment, the isomerized
base oil has a kinematic viscosity between 1.5 and 4.0 mm.sup.2/s
and a Noack volatility less than the Noack volatility calculated by
the following equation: 160-40 (Kinematic Viscosity at 100.degree.
C.).
[0047] In one embodiment, the isomerized base oil has a kinematic
viscosity at 100.degree. C. in the range of 2.4 and 3.8 mm.sup.2/s
and a Noack volatility less than an amount defined by the equation:
900.times.(Kinematic Viscosity at 100.degree. C.).sup.-2.8-15). For
kinematic viscosities in the range of 2.4 and 3.8 mm.sup.2/s, the
equation: 900.times.(Kinematic Viscosity at 100.degree.
C.).sup.-2.8-15) provides a lower Noack volatility than the
equation: 160-40 (Kinematic Viscosity at 100.degree. C.)
[0048] In one embodiment, the isomerized base oil is made from a
process in which the highly paraffinic wax is hydroisomerized under
conditions for the base oil to have a kinematic viscosity at
100.degree. C. of 3.6 to 4.2 mm.sup.2/s, a viscosity index of
greater than 130, a wt % Noack volatility less than 12, a pour
point of less than -9.degree. C.
[0049] In one embodiment, the isomerized base oil has an
auto-ignition temperature (AIT) greater than the AIT defined by the
equation: AIT in .degree. C.=1.6.times.(Kinematic Viscosity at
40.degree. C., in mm.sup.2/s)+300. In a second embodiment, the base
oil as an AIT of greater than 329.degree. C. and a viscosity index
greater than 28.times.Ln (Kinematic Viscosity at 100.degree. C., in
mm.sup.2/s)+100.
[0050] In one embodiment, the isomerized base oil has a relatively
low traction coefficient, specifically, its traction coefficient is
less than an amount calculated by the equation: traction
coefficient=0.009.times.Ln (kinematic viscosity in
mm.sup.2/s)-0.001, wherein the kinematic viscosity in the equation
is the kinematic viscosity during the traction coefficient
measurement and is between 2 and 50 mm.sup.2/s. In one embodiment,
the isomerized base oil has a traction coefficient of less than
0.023 (or less than 0.021) when measured at a kinematic viscosity
of 15 mm.sup.2/s and at a slide to roll ratio of 40%. In another
embodiment the isomerized base oil has a traction coefficient of
less than 0.017 when measured at a kinematic viscosity of 15
mm.sup.2/s and at a slide to roll ratio of 40%. In another
embodiment the isomerized base oil has a viscosity index greater
than 150 and a traction coefficient less than 0.015 when measured
at a kinematic viscosity of 15 mm.sup.2/s and at a slide to roll
ratio of 40 percent.
[0051] In some embodiments, the isomerized base oil having low
traction coefficients also displays a higher kinematic viscosity
and higher boiling points. In one embodiment, the base oil has a
traction coefficient less than 0.015, and a 50 wt % boiling point
greater than 565.degree. C. (1050.degree. F.). In another
embodiment, the base oil has a traction coefficient less than 0.011
and a 50 wt % boiling point by ASTM D 6352-04 greater than
582.degree. C. (1080.degree. F.).
[0052] In some embodiments, the isomerized base oil having low
traction coefficients also displays unique branching properties by
NMR, including a branching index less than or equal to 23.4, a
branching proximity greater than or equal to 22.0, and a Free
Carbon Index between 9 and 30. In one embodiment, the base oil has
at least 4 wt % naphthenic carbon, in another embodiment, at least
5 wt % naphthenic carbon by n-d-M analysis by ASTM D 3238-95
(Reapproved 2005).
[0053] In one embodiment, the isomerized base oil is produced in a
process wherein the intermediate oil isomerate comprises paraffinic
hydrocarbon components, and in which the extent of branching is
less than 7 alkyl branches per 100 carbons, and wherein the base
oil comprises paraffinic hydrocarbon components in which the extent
of branching is less than 8 alkyl branches per 100 carbons and less
than 20 wt % of the alkyl branches are at the 2 position. In one
embodiment, the FT base oil has a pour point of less than
-8.degree. C.; a kinematic viscosity at 100.degree. C. of at least
3.2 mm.sup.2/s; and a viscosity index greater than a viscosity
index calculated by the equation of=22.times.Ln (kinematic
viscosity at 100.degree. C.)+132.
[0054] In one embodiment, the base oil comprises greater than 10
wt. % and less than 70 wt. % total molecules with cycloparaffinic
functionality, and a ratio of weight percent molecules with
monocycloparaffinic functionality to weight percent molecules with
multicycloparaffinic functionality greater than 15.
[0055] In one embodiment, the isomerized base oil has an average
molecular weight between 600 and 1100, and an average degree of
branching in the molecules between 6.5 and 10 alkyl branches per
100 carbon atoms. In another embodiment, the isomerized base oil
has a kinematic viscosity between about 8 and about 25 mm.sup.2/s
and an average degree of branching in the molecules between 6.5 and
10 alkyl branches per 100 carbon atoms.
[0056] In one embodiment, the isomerized base oil is obtained from
a process in which the highly paraffinic wax is hydroisomerized at
a hydrogen to feed ratio from 712.4 to 3562 liter H.sub.2/liter
oil, for the base oil to have a total weight percent of molecules
with cycloparaffinic functionality of greater than 10, and a ratio
of weight percent molecules with monocycloparaffinic functionality
to weight percent molecules with multicycloparaffinic functionality
of greater than 15. In another embodiment, the base oil has a
viscosity index greater than an amount defined by the equation:
28.times.Ln (Kinematic viscosity at 100.degree. C.)+95. In a third
embodiment, the base oil comprises a weight percent aromatics less
than 0.30; a weight percent of molecules with cycloparaffinic
functionality greater than 10; a ratio of weight percent of
molecules with monocycloparaffinic functionality to weight percent
of molecules with multicycloparaffinic functionality greater than
20; and a viscosity index greater than 28.times.Ln (Kinematic
Viscosity at 100.degree. C.)+110. In a fourth embodiment, the base
oil further has a kinematic viscosity at 100.degree. C. greater
than 6 mm.sup.2/s. In a fifth embodiment, the base oil has a weight
percent aromatics less than 0.05 and a viscosity index greater than
28.times.Ln (Kinematic Viscosity at 100.degree. C.)+95. In a sixth
embodiment, the base oil has a weight percent aromatics less than
0.30, a weight percent molecules with cycloparaffinic functionality
greater than the kinematic viscosity at 100.degree. C., in
mm.sup.2/s, multiplied by three, and a ratio of molecules with
monocycloparaffinic functionality to molecules with
multicycloparaffinic functionality greater than 15.
[0057] In one embodiment, the isomerized base oil contains between
2 and 10% naphthenic carbon as measured by n-d-M. In one
embodiment, the base oil has a kinematic viscosity of 1.5-3.0
mm.sup.2/s at 100.degree. C. and 2-3% naphthenic carbon. In another
embodiment, a kinematic viscosity of 1.8-3.5 mm.sup.2/s at
100.degree. C. and 2.5-4% naphthenic carbon. In a third embodiment,
a kinematic viscosity of 3-6 mm.sup.2/s at 100.degree. C. and
2.7-5% naphthenic carbon. In a fourth embodiment, a kinematic
viscosity of 10-30 mm.sup.2/s at 100.degree. C. and greater than
5.2% naphthenic carbon.
[0058] In one embodiment, the isomerized base oil has an average
molecular weight greater than 475; a viscosity index greater than
140, and a weight percent olefins less than 10. The base oil
improves the air release and low foaming characteristics of the
mixture when incorporated into the metalworking fluid.
[0059] In one embodiment, the isomerized base oil is a FT base oil
having a kinematic viscosity at 100.degree. C. between 2 mm.sup.2/s
and 6 mm.sup.2/s; a kinematic viscosity at 40.degree. C. between 7
mm.sup.2/s and 20 mm.sup.2/s; CCS viscosity of less than 2300 mPas
at -35.degree. C.; pour point in the range of -20 and -40.degree.
C.; molecular weight of 300-500; density in the range of 0.800 to
0.820; paraffinic carbon in the range of 93-97%; naphthenic carbon
in the range of 3-7%; Oxidator BN of 30 to 60 hours; and Noack
volatility in wt. % of 8 to 20 as measured by ASTM D5800-05
Procedure B.
[0060] In another embodiment for an anti-mist performance, the
isomerized base oil is a FT base oil of "light" range viscosity
having a kinematic viscosity at 100.degree. C. between 2 mm.sup.2/s
and 3 mm.sup.2/s; a kinematic viscosity at 40.degree. C. between 7
mm.sup.2/s and 25 mm.sup.2/s; a viscosity index of 120-150; pour
point in the range of -20 and -50.degree. C.; molecular weight of
300-500; density in the range of 0.800 to 0.820; paraffinic carbon
in the range of 92-97%; naphthenic carbon in the range of 3-7%;
Oxidator BN of 30 to 60 hours; and Noack volatility in wt. % of 8
to 60 as measured by ASTM D5800-05 Procedure B. In another
embodiment, the isomerized base oil is a FT base oil of "medium"
range viscosity, having a kinematic viscosity at 100.degree. C.
between 5 mm.sup.2/s and 7 mm.sup.2/s; a kinematic viscosity at
40.degree. C. between 25 mm.sup.2/s and 50 mm.sup.2/s; a viscosity
index of 140-160; pour point in the range of -15 and -25.degree.
C.; molecular weight of 450-550; density in the range of 0.820 to
0.830; paraffinic carbon in the range of 90-95%. In a third
embodiment, the base oil comprises a mixture of "light" and
"medium" range viscosity FT base oils.
[0061] In one embodiment, the metalworking fluid employs at least
one of the isomerized base oils described above. In another
embodiment, the composition consists essentially of at least a
Fischer-Tropsch base oil. In yet another embodiment, the
metalworking fluid employs at least an isomerized based oil as the
base oil matrix and optionally 5 to 95 wt. % of at least another
type of oil, e.g., lubricant base oils selected from Group I, II,
III, IV, V, and VI lubricant base oils as defined in the API
Interchange Guidelines, and mixtures thereof. In a fourth
embodiment, the metalworking fluid employs an isomerized based oil
and 5 to 20 wt. % of at least another type of oil. Examples include
conventionally used mineral oils, synthetic hydrocarbon oils or
synthetic ester oils, or mixtures thereof depending on the
application. Mineral lubricating oil base stocks can be any
conventionally refined base stocks derived from paraffinic,
naphthenic and mixed base crudes. Synthetic lubricating oils that
can be used include esters of glycols and complex esters. Other
synthetic oils that can be used include synthetic hydrocarbons such
as polyalphaolefins; alkyl benzenes, e.g., alkylate bottoms from
the alkylation of benzene with tetrapropylene, or the copolymers of
ethylene and propylene; silicone oils, e.g., ethyl phenyl
polysiloxanes, methyl polysiloxanes, etc., polyglycol oils, e.g.,
those obtained by condensing butyl alcohol with propylene oxide;
etc. Other suitable synthetic oils include the polyphenyl ethers,
e.g., those having from 3 to 7 ether linkages and 4 to 8 phenyl
groups. Other suitable synthetic oils include polyisobutenes, and
alkylated aromatics such as alkylated naphthalenes.
[0062] Additional Components: The metalworking fluid in one
embodiment is characterized as having reduced mist formation, lower
foaming tendency, and better air release properties compared to
compositions of the prior art. Depending on the applications, e.g.,
straight oils (neat oils) or soluble oils, the metalworking fluid
may contain applicable additives known in the art to improve the
properties of the composition in amounts ranging from 0.10 to 40
wt. %. These additives include metal deactivators; corrosion
inhibitors; antimicrobial; anticorrosion; emulsifying agents;
couplers; extreme pressure agents; antifriction; antirust agents;
polymeric substances; anti inflammatory agents; bactericides;
antiseptics; antioxidants; chelating agents such as edetic acid
salts, and the like; pH regulators; antiwear agents including
active sulphur anti-wear additive packages and the like; a
metalworking fluid additive package containing at least one of the
aforementioned additives.
[0063] In different embodiments, there is no need to add any of the
anti-mist additives (mist control agents or anti-misting agents)
nor the foam inhibitors in the prior art, for a metalworking fluid
that consists essentially of the base oil matrix comprising the
isomerized base oil and at least an additive other than an
anti-misting agent/foam inhibitor. However, in other embodiments
and depending on the end-use applications, small quantities of
additives such as anti-misting agents may be optionally added in an
amount ranging from 0.05 to 5.0% by vol. in one embodiment and less
than 1 wt. % in other embodiments. Non-limiting examples include
rhamsan gum, hydrophobic and hydrophilic monomers, styrene or
hydrocarbyl-substituted styrene hydrophobic monomers and
hydrophilic monomers, oil soluble organic polymers ranging in
molecular weight (viscosity average molecular weight) from about
0.3 to over 4 million such as isobutylene, styrene, alkyl
methacrylate, ethylene, propylene, n-butylene vinyl acetate, etc.
In one embodiment, polymethylmethacrylate or poly(ethylene,
propylene, butylene or isobutylene) in the molecular weight range 1
to 3 million is used.
[0064] In some embodiments and for certain applications, a small
amount of foam inhibitors in the prior art can also be added to the
composition in an amount ranging from 0.05 to 15.0 wt. %.
Non-limiting examples include polydimethylsiloxanes, often
trimethylsilyl terminated, alkyl polymethacrylates,
polymethylsiloxanes, an N-acylamino acid having a long chain acyl
group and/or a salt thereof, an N-alkylamino acid having a long
chain alkyl group and/or a salt thereof used concurrently with an
alkylalkylene oxide and/or an acylalkylene oxide, acetylene diols
and ethoxylated acetylene diols, silicones, hydrophobic materials
(e.g. silica), fatty amides, fatty acids, fatty acid esters, and/or
organic polymers, modified siloxanes, polyglycols, esterified or
modified polyglycols, polyacrylates, fatty acids, fatty acid
esters, fatty alcohols, fatty alcohol esters, oxo-alcohols,
fluorosurfactants, waxes such as ethylenebistereamide wax,
polyethylene wax, polypropylene wax, ethylenebisstereamide wax, and
paraffinic wax, ureum. The foam control agents can be used with
suitable dispersants and emulsifiers. Additional active foam
control agents are described in "Foam Control Agents", by Henry T.
Kemer (Noyes Data Corporation, 1976), pages 125-162.
[0065] In various embodiments, the metalworking fluid further
comprises anti-friction agents include overbased sulfonates,
sulfurized olefins, chlorinated paraffins and olefins, sulfurized
ester olefins, amine terminated polyglycols, and sodium dioctyl
phosphate salts. In yet other embodiment, the composition further
comprises corrosion inhibitors including carboxylic/boric acid
diamine salts, carboxylic acid amine salts, alkanol amines, alkanol
amine borates and the like.
[0066] In various embodiments, the metalworking fluid further
comprise oil soluble metal deactivators in an amount of 0.01 to 0.5
vol % (based on the final oil volume). Non-limiting examples
include triazoles or thiadiazoles, specifically aryl triazoles such
as benzotriazole and tolyltriazole, alkyl derivatives of such
triazoles, and benzothiadiazoles such as R(C.sub.6H.sub.3)N.sub.2S
where R is H or C.sub.1 to C.sub.10 alkyl. Suitable materials are
available from Ciba Geigy under the tradenames Irgamet and Reomet
or from Vanderbilt Chemical Corporation under the Vanlube
tradename.
[0067] In one embodiment, such as when the composition serves the
dual purpose of cutting fluid and machine lube oil, a small amount
of at least an antioxidant in the range 0.01 to 1.0 weight % can be
added. Non-limiting examples include antioxidants of the aminic or
phenolic type or mixtures thereof, e.g., butylated hydroxy toluene
(BHT), bis-2,6-di-t-butylphenol derivatives, sulfur containing
hindered phenols, and sulfur containing hindered bisphenol.
[0068] In some embodiments, the metalworking fluid further
comprises 0.1 to 20 wt. % of at least an extreme-pressure agent.
Non-limiting examples of extreme pressure agents include zinc
dithiophosphate, molybdenum oxysulfide dithiophosphate, molybdenum
oxysulfide thithiocarbamate, molybdenum amine compounds, sulfurized
oils and fats, sulfurized fatty acids, sulfurized esters,
sulfurized olefins, dihydrocarbyl polysulfides, thiocarbamates,
thioterpenes, dialkyl thiodipropionates, and the like.
[0069] In addition to the above additives, various other
conventional additives can be added to such extent that they do not
inhibit the effects of the metalworking fluid. Examples include
fatty acids and salts thereof, polyhydric alcohols such as
propylene glycol, glycerin, butylene glycerol, and the like;
surfactants such as anionic surfactants, amphoteric surfactants,
nonionic surfactants, and the like; and boron nitride dispersed in
a dispersant such as a surfactant.
[0070] Method for Making: The optional additives used in
formulating the metalworking fluid composition can be blended into
the base oil matrix individually or in various sub-combinations. In
one embodiment, all of the components are blended concurrently
using an additive concentrate (i.e., additives plus a diluent, such
as a hydrocarbon solvent). The use of an additive concentrate takes
advantage of the mutual compatibility afforded by the combination
of ingredients when in the form of an additive concentrate.
[0071] In another embodiment, the metalworking fluid is prepared by
mixing the base oil matrix with the optional additives and/or
additive package(s) at an appropriate temperature, such as
approximately 60.degree. C., until homogeneous, for use as a
straight oil cutting fluid. In yet another embodiment, the
emulsifying agents may be added to the metalworking fluid to form
an oil-in-water emulsion.
[0072] Properties: In one embodiment, the metalworking fluid
composition is characterized as having reduced mist formation, low
foaming tendency and excellent air release properties. The foaming
tendency of the metalworking fluids can be measured using the ASTM
D892-95 foam test. In one embodiment, the metalworking fluid when
evaluated under ASTM D892-06 method shows a sequence II foam
tendency foam height of less than 50 mL. In yet another embodiment,
the metalworking fluid shows a sequence II foam height of less than
40 mL. In a third embodiment, a sequence II foam height of less
than 30 mL. In a fifth embodiment, the sequence II foam height is
less than 20 mL. In a six embodiment, none can be measured (0
mL).
[0073] In one embodiment, the metalworking fluid shows a sequence I
foam tendency by ASTM D 892-03 of less than 100 mL. In another
embodiment, the fluid has a sequence I foam tendency of less than
50 mL. In a third embodiment, a sequence I foam tendency of less
than 30 mL.
[0074] In one embodiment, the metalworking fluid has a number of
minutes to 3 mL emulsion at 54.degree. C. by ASTM D 1401-02 of
equal or less than 30. In yet another embodiment, the fluid has a
number of minutes to 3 mL emulsion at 82.degree. C. by ASTM D
1401-02 equal to or less than 60.
[0075] Air release properties can be measured using the ASTM D 3427
(2003) method for gas bubble separation time of petroleum oil to
measure the ability of a fluid to separate entrained gas. In one
embodiment, the metalworking fluid has an air release time at
50.degree. C. of less than 0.60 minutes as measured according to
ASTM D 3427 (2003). In a second embodiment, an air release time of
less than 1/2 minutes.
[0076] In one embodiment, the metalworking fluid exhibits reduced
mist formation property and imparts aerosol control or particulate
control to the fluid, e.g., having 5 to 50% mist reduction compared
to metalworking fluids comprising base oil Group I in the prior
art. Mist reduction experiments can be measured according to
similar to the aerosol (mist) formation test as described in
"Polymer Additives as Mist Suppressants in Metal Cutting Fluids,"
by Marano et al., Journal of the Society of Tribologists and
Lubrication Engineers, October 1995, pp. 25-35. In one embodiment,
the metalworking fluid without any addition of anti-mist additives
has an average mist accumulation rate of less than 300 mg/mm.sup.3
in the first 30 seconds (after start) of the aerosol mist formation
test. In another embodiment, the metalworking fluid without any
mist additive has an average mist accumulation rate of less than
250 mg/mm.sup.3 in the first 30 seconds of the aerosol mist
formation test. In a third embodiment, the average mist
accumulation rate is less than 200 mg/mm.sup.3 in the first 30
seconds of the test. In a fourth embodiment, the average mist
accumulation rate is less than 150 mg/mm.sup.3 in the first 60
seconds of the test.
[0077] In one embodiment, the metalworking fluid composition is
readily biodegradable, with the base oil having an OECD 301D level
ranging from 30 to 95%. In one embodiment, the metalworking fluid
has a kinematic viscosity at 40.degree. C. of 10-14 mm.sup.2/s and
an OECD 301D biodegrability of >=60%. In a second embodiment,
the composition has a kinematic viscosity at 40.degree. C. of less
than 10 mm.sup.2/s and an OECD 301D biodegrability of >=80%. In
a third embodiment, the composition has a kinematic viscosity at
40.degree. C. of less than 8 mm.sup.2/s and an OECD 301D
biodegrability of >=90%. In a fifth embodiment, the metalworking
fluid has a biodegradability of at least 30% as measured according
to OECD 301D.
[0078] Metalworking fluids can be characterized as suitable or
unsuitable for extreme pressure applications. A fluid that is
considered as suitable for extreme pressure is one that prevents
sliding metal surfaces from seizing under extreme pressure
conditions. The seizing of metal surfaces result from friction
between opposing asperities. Asperities are microscopic projections
on metal surfaces resulting from metalworking operations. One
technique for measuring extreme pressure properties of a fluid is
to measure a load force between sliding surfaces which can be
sustained by lubricant without seizing of the sliding surfaces.
Such a technique is described as a Falex load test, which is an
ASTM standard test for fluid lubricants (ASTM D-3233 (2003)). In
one embodiment, the metalworking fluid is characterized has having
a Falex reference wear of less than ten teeth. In another
embodiment, the metalworking fluid is characterized as having a
Falex reference load of greater than about 4,500 pounds force.
[0079] In one embodiment, the metalworking fluid is characterized
as having excellent lubricating property, specifically lubricating
surfaces in sliding contacts, as measured in a Four-Ball Wear Test
per ASTM D4172-94(2004)e1. In one embodiment, the metalworking
fluid has a Four-Ball wear scar diameter of less than about 0.07
mm.
[0080] In some applications and with the use of isomerized base
oils having a low kinematic viscosity, the metalworking fluid is
characterized has having a smooth liquid flow for excellent
circulation in a pump. Moreover, the metalworking fluid has an
excellent which can prevent frictional heat from being produced
between a tool and a workpiece, so that the effective tool life can
be increased.
[0081] Applications: In one embodiment, the metalworking fluid is
used in the production of semiconductors, plant equipment, and auto
parts, etc. wherein the shape of the final object, e.g., silicon
wafer or machine part, is obtained by with or without the
progressive removal of metal or silicon. Non-limiting examples of
the operations include cutting, drilling, boring, honing,
broaching, grinding, forming, stamping, casting, forging, rolling,
piercing, coining, drawing, press forming, deburring, milling,
grooving, tapping, chamfering, broaching, reaming, honing, lapping,
straightening, and drawing.
[0082] In one embodiment of a metalworking operation, the
metalworking fluid is applied to the contact zone between tool and
workpiece. The fluid may be applied by a variety of methods,
including immersing the contact zone in the fluid, spraying the
fluid into the contact zone, flooding the contact zone with fluid,
pumping a stream of fluid into the contact zone, periodically
wetting the tool or the workpiece with lubricating fluid, or any
means of constantly or intermittently applying the lubricant to the
contact zone between the tool and the workpiece.
EXAMPLES
[0083] Unless specified otherwise, the compositions are prepared by
mixing the components in the amounts indicated in the
Examples/Tables. The components used in the Examples are listed
below.
[0084] EP agent is a commercially available sulfurized polymerized
ester, 10% inactive sulphur extreme-pressure agent.
[0085] HYNAP.TM. N100HTS hydrotreated, naphthenic oil (Group V) is
from San Joaquin Refining Oil, Inc. of Bakersfield, Calif.
[0086] Ashland.TM. 100SN Group 1 oil is from Ashland Inc.
[0087] Chevron.TM. 100R group 2 oil, Chevron.TM. 100R group 3 oil,
and Chevron Synfluid 4 cSt PAO oil are all from Chevron Corporation
of San Ramon, Calif.
[0088] Additive 2 is a sulfurized vegetable fatty acid ester.
Defoamer is an acrylate oligomer antifoam/defoamer. Additive CAS is
a commercially available overbased calcium sulphonate PEP
metalworking additive containing carbonated alkylbenzene sulfonate.
Additive SO is a sulfurized olefin.
[0089] Mineral seal oil (MSO) having a visocisty of 3.39
mm.sup.2/sec at 40.degree. C., and basestock oils SN 100 (density
of 0.864 and viscosity of 20.6 mm.sup.2/sec at 40.degree. C.), SN
150 and SN 600 (API Group 1) are commercially available from a
number of sources.
[0090] GTL Fischer-Tropsch derived base oils GST0449, FTBO L, FTBO
XL, FTBO XXL, and FTBO M are from Chevron Corp. Properties of the
Fischer-Tropsch derived base oils used in the Examples are shown in
Table 3.
[0091] Anti-mist agent 1 is a methacrylate copolymer. Anti-mist
agent 2 is a commercially available high molecular weight oil
soluble polymer tackifier.
Examples 1-6
[0092] A number of metalworking fluid compositions having
components as listed in Table 1 were formulated and their
properties were measured using various standard test methods: ASTM
D1401-02 for Water Separability of Petroleum Oils and Synthetic
Fluids; ASTM D 3427 (2003) Standard Test Method for Air Release
Properties of Petroleum Oils; and ASTM D892-95 Foam Stability
Sequence Test. As shown in the table, the example incorporating the
isomerized base oil shows low foaming tendency (foam height of nil)
and air release property that is comparable if not better than the
prior art oil (in view of the test repeatability of 1 min.).
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4
Example 5 Example 6 Group V Group 1 Group 2 Group 3 PAO GTL BST
Sample ID wt % wt % wt % wt % wt % wt % SJR Hynap N100HTS - Group V
95 -- -- -- -- -- Ashland 100 SN - Group 1 -- 95 -- -- -- --
Chevron 100 R - Group 2 -- -- 95 -- -- -- Chevron UCBO 4R - Group 3
-- -- -- 95 -- -- Chevron Synfluid, 4 cSt - PAO -- -- -- -- 95 --
GTL BST isomerized base oil -- -- -- -- -- 95 EP agent 5 5 5 5 5 5
Kinematic Viscosity @ 40.degree. C., cSt 19.91 20.51 20.70 18.30
17.76 18.60 Air Release @50 C., D3427, min 0.72 0.88 0.5 0.42
<0.42 <0.42 Foam Sequence I-III, D892 Seq. I, 24 C.,
Tendency, mL foam 220 70 80 30 0 0 Seq. I, Stability, mL after 10
min. 0 0 0 0 0 0 Seq. II, 93.5 C., Tendency, mL foam 30 30 25 20 0
0 Seq. II, Stability, mL after 10 min. 0 0 0 0 0 0 Seq. III, 24 C.,
Tendency, mL foam 140 100 80 40 0 0 Seq. III, Stability, mL after
10 min. 0 0 0 0 0 0 Water Separability, D1401 @ 54 C. o-w-e, mL
2/0/78 2/0/78 2/0/78 2/0/78 2/0/78 2/2/76 Time, min 30 30 30 30 30
30 Water Separability, D1401 @ 82 C. o-w-e, mL 6/0/74 6/0/74 5/0/75
9/0/71 7/0/73 6/0/74 Time, min 60 60 60 60 60 60
Examples 7-13
[0093] A number of metalworking fluid compositions having
components as listed in Table 2 were formulated and their
properties were measured/recorded. Examples 11-13 compare the
compositions each with 0.25 wt. % of an anti-mist agent added (a
high molecular weight oil soluble polymer tackifier).
[0094] The samples were subject to an aerosol (mist) formation
experiment similar to the one described in "Polymer Additives as
Mist Suppressants in Metal Cutting Fluids," by Marano et al.,
Journal of the Society of Tribologists and Lubrication Engineers,
October 1995, pp. 25-35. Basically in the test, metalworking fluid
(in 100 mL sample) was supplied to a coaxial atomizer's tip through
a tube (e.g., ID of 0.0011 m) by a syringe pump at constant flow
rates up to 0.0084 litre/min. Compressed air was supplied through
the annulus between the outer and inner tubes (ID 0.0021 m and OD
0.0013 m, respectively) at flow rates up to 35 litres/min. Mist
generated by the atomizer was directed to a long wide plexiglass
duct of square cross section or chamber (e.g., a 12'' by 12'' by
18'' chamber). The amount of mist generated as a function of time
(as mg/mm.sup.3 over a duration of 5 minutes) was captured by a
datalogger and recorded. In the experiments, a portable, real time
aerosol monitor DataRAM.RTM. [MIE Instruments Inc., Bedford Mass.]
was used as the datalogger to continuously quantify the mist levels
generated. The DataRAM is a nephelometric monitor used to measure
airborne particle concentration by sensing the amount of light
scattered by the population of particles passing through a sampling
volume.
[0095] For all of the samples, most of the mist was generated at
the beginning of the test. After atomizing, the mist tended to drop
to the bottom of the container and thereby showing a drop in the
amount of mist collected.
[0096] Measurements from the aerosol (mist) formation experiments
were plotted in FIGS. 1-3 as a function of time. The results show
that generally, metalworking fluid compositions containing
Fischer-Tropsch derived base oils result in significantly less mist
formation than the base oils of the prior art, with a reduction in
mist formation of at least 10% in some examples to up to 75% or
more in the first 30 seconds of the aerosol mist formation test.
Example 10 with the isomerized base oil performs better (with
reduced mist formation) compared to Example 9 with a mineral group
I base oil and even with 2 wt. % anti-mist additive. In FIG. 3, all
examples (#11-13) with the addition of a high molecular weight oil
soluble polymer tackifier as a powerful (and expensive) anti-mist
additive show comparable performance.
TABLE-US-00002 TABLE 2 Ex. 11 Ex. 12 Ex. 13 Ex. 7 Ex. 8 Ex. 9 Ex.
10 ZX12A- ZX12B- ZX12C Components wt. % ZX12A ZX12B ZX46A ZX46B
antimist antimist antimist SN 100 51.98 -- -- -- 51.98 -- -- SN 150
-- -- 70.98 -- -- -- -- SN 600 -- -- 15 -- -- -- -- MSO 36 -- -- --
36 -- -- FTBO M -- -- -- 87.98 -- -- -- FTBO L -- -- -- -- -- -- --
FTBO XL -- 16.21 -- -- -- -- 16.21 FTBO XXL -- 71.77 -- -- -- 87.98
71.77 Anti-mist agent 1 -- -- 2 -- -- -- -- Anti-mist agent 2 -- --
-- -- 0.25 0.25 0.25 CAS alkylbenzene 4 4 4 4 4 4 4 Sulfurized
olefin 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Additive 2 5.5 5.5 5.5 5.5 5.5
5.5 5.5 Defoamer 0.02 0.02 0.02 0.02 0.02 0.02 0.02
Visc.@40.degree. C. m.sup.2/sec 10.4 9.89 48.12 45.19 10.7 9.61
9.89 Density @15.degree. C. .8626 .8264 -- -- .8626 .826 .826
Visc.@100.degree. C. m.sup.2/sec 2.84 2.8 -- -- -- -- -- VI 122 141
-- -- -- -- -- Flash point .degree. C. 148 178 -- -- -- -- -- Color
L3.5 L3.5 -- -- -- -- --
TABLE-US-00003 TABLE 3 Properties FTBO-XXL FTBO-XL FTBO-L FTBO-M
GTL BST Kinematic Viscosity @ 40.degree. C., cSt 7.658 11.16 17.07
34.13 17.74 Kinematic Viscosity @ 100.degree. C., cSt 2.333 2.988
4.028 6.134 4.12 Viscosity Index 124 125 139 156 138 Cold Crank
Viscosity @ -40.degree. C., cP 1,525 Cold Crank Viscosity @
-35.degree. C., cP 578 1,524 6048 1,596 Cold Crank Viscosity @
-30.degree. C., cP 361 866 3200 941 Pour Point, .degree. C. -46 -36
-28 -18 -26 n-d-m Molecular Weight, gm/mol (VPO) 314 375 436 508
431 Density, gm/mL 0.8026 0.8059 0.8122 0.824 0.8128 Refractive
Index 1.4485 1.4507 1.454 1.4596 1.4541 Paraffinic Carbon, % 93.13
96.97 95.82 92.84 95.99 Naphthenic Carbon, % 6.87 3.03 4.18 7.16
4.01 Aromatic Carbon, % 0.00 0.00 0.00 0 0 Oxidator BN, hrs 35.9
56.27 39.97 41.02 ANTEK SULFUR <2 <1 <1 <2 LOW LEVEL
NITROGEN <0.1 <.1 <0.1 <0.1 Noack, wt. % 60.69 26.8
10.72 3.15 10.22 Saybolt Color +33.6 Aromatics Total 0.00261 0
0.00082 COC Flash Point, .degree. C. 192 206 226 254 232 SIMDIST
TBP (WT %), F TBP @0.5 583 679 726 799 732 TBP @5 622 701 754 831
758 TBP @10 636 709 766 846 770 TBP @20 654 720 780 865 784 TBP @30
667 728 791 880 795 TBP @40 678 735 800 894 805 TBP @50 688 741 809
906 813 TBP @60 697 748 818 920 822 TBP @70 706 756 828 935 832 TBP
@80 715 764 839 952 843 TBP @90 727 774 853 976 857 TBP @95 735 782
864 994 867 TBP @99.5 753 802 884 1034 887 FIMS Saturates 72.7 75.3
75 75.3 1-Unsaturation 19.3 23.2 24 23.6 2-Unsaturation 3.9 1.1 0.8
0.9 3-Unsaturation 2 0.2 0.1 0.1 4-Unsaturation 1.7 0 0 0
5-Unsaturation 0.5 0 0 0 6-Unsaturation 0 0.2 0.1 0.1 Branching
Index 30.21 28.85 26.95 27.25 Branching Proximity 14.05 12.77 14.43
14.83 Alkyl Branches per Molecule 2.17 2.63 2.57 2.9 Methyl
Branches per Molecule 1.90 2.07 2 2.26 FCI 3.15 3.42 4.5 4.56
FCI/END Methyl Ratio 2.50 2.33 3.66 3.1 Alkyl Branches per 100
Carbons 9.67 9.83 8.25 9.42 Methyl Branches per 100 Carbons 8.48
7.74 6.41 7.35 % Olefins by Proton NMR 0.00 0.12 0.23 0.32
Monocycloparaffin (FIMS 1-unsat- 23.88 NMR Olefins)
Multicycloparaffin (FIMS 2-Unsat- 0.99739 6Unsat - HPLC-UV
Aromatics) Mono/Multi ratio 23.94
[0097] For the purposes of this specification and appended claims,
unless otherwise indicated, all numbers expressing quantities,
percentages or proportions, and other numerical values used in the
specification and claims, are to be understood as being modified in
all instances by the term "about." Accordingly, unless indicated to
the contrary, the numerical parameters set forth in the following
specification and attached claims are approximations that may vary
depending upon the desired properties sought to be obtained by the
present invention. It is noted that, as used in this specification
and the appended claims, the singular forms "a," "an," and "the,"
include plural referents unless expressly and unequivocally limited
to one referent. As used herein, the term "include" and its
grammatical variants are intended to be non-limiting, such that
recitation of items in a list is not to the exclusion of other like
items that can be substituted or added to the listed items.
[0098] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to make and use the invention. The patentable
scope is defined by the claims, and may include other examples that
occur to those skilled in the art. Such other examples are intended
to be within the scope of the claims if they have structural
elements that do not differ from the literal language of the
claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
[0099] All citations referred herein are expressly incorporated
herein by reference.
* * * * *