Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FORMULATION OF A METALWORKING FLUID
RELATED APPLICATIONS
[0001] [Not Applicable]
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] [Not Applicable]
[MICROFICHE/COPYRIGHT REFERENCE]
[0003] [Not Applicable]
BACKGROUND OF THE INVENTION
[0004] This invention relates to non-oil containing metalworking
fluids, also
known as synthetic metalworking fluids.
[0005] Metalworking is defined as shaping metallic work-pieces to conform
to a desired set of geometric specifications. Metalworking comprises two basic
categories, cutting and forming. Cutting operations include grinding, turning,
milling, tapping, broaching and hobbing. Forming operations include hot and
cold
rolling, drawing, forging, stamping and blanking.
[0006] Metalworking fluids are essential in both cutting and forming
operations. They must provide for lubrication between the work-piece and tool
and also provide cooling by removing the heat generated during the
metalworking
operations.
[0007] Lubrication is defined as the reduction of friction between
two
moving surfaces. The two main types of lubrication in metalworking operations
are hydrodynamic and boundary or extreme pressure (EP). Hydrodynamic
lubrication involves separating the moving surfaces by a film of fluid
lubricant.
Boundary or EP lubrication minimizes the wear experienced when surfaces rub
together. Polymeric lubricity agents can provide both types of lubrication.
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[0008]
Metalworking fluids are classified into two main segments, oil
containing and non-oil containing. The oil-containing segment comprises
straight
oils, soluble oils, and semi-synthetics, all of which utilize mineral oil as
the
primary lubricant. The non-oil segment is known as synthetics, which include
compositions of lubricity-producing additives in an aqueous transport system
or
diluent. The soluble oil and semi-synthetic products enjoy an 80% share of the
market, the non-water reducible straight oils segment have a 10% share, while
the synthetics comprise 10% of the market.
[0009]
Existing types of metalworking fluids have advantages and
drawbacks. The oil containing products have the advantages of excellent
lubricity, a wide range of applications, and barrier protection of sumps from
corrosion. The drawbacks of oil-containing metalworking fluids are that water
hardness often impacts the fluid stability, foaming is a frequent problem due
to
their inclusion of higher detergency emulsifiers, they entrain a greater dirt
load,
they cost more to dispose of and to clean out of a tank, and they have greater
microbial problems.
[0010] The
use of synthetics is encouraged for a variety of factors from
environmental issues to the microbial advantages. However, most customers
continue to use oil containing products because of their good lubricity at a
low
comparative cost, and because of the increased maintenance corrosion issues
associated with synthetics. Synthetic sumps, lacking the protective barrier
film
provided by oil, can corrode and "freeze" machining system bolts, making
maintenance difficult. Additionally, high lubricity performance synthetic
products
are expensive when compared with similar lubricity performance oil containing
products. Their reduced physical lubricity on a cost basis with semi-
synthetics
restrains their use in heavy-duty operations.
BRIEF SUMMARY OF THE INVENTION
[0011] An
aspect of the invention relates to an entirely new class of
metalworking fluid products. This new chemistry incorporates a synergistic
blend
of carboxylic acid salts, boundary lube fatty acids, and EO/PO polymers, which
react to form a moiety which, in certain embodiments, may optionally have
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enhanced particle size, exceptional lubricity or both. In addition, for
certain
embodiments use dilutions are opaque and mimic the appearance of oil-based
solutions.
[0012] In certain embodiments, the metalworking fluid compositions can
have a volume average particle size of 125 nm or greater when diluted between
0.1 and 50 percent by volume. The compositions comprise:
(a) one or more polymeric lubricity agents;
(b) one or more carboxylic acid salts;
(c) one or more emulsifying or dispersing agents; and
(d) a transport component.
[0012a] In certain embodiments, the present invention concerns an
alkanolamine-free and oil-free metalworking fluid composition, comprising:
(a) 10 to 20 percent by volume of one or more block copolymer which
consists of a central polyoxypropylene block and a polyoxyethylene chain
at each end of the polyoxypropylene block;
(b) 5 to 10 percent by volume of one or more carboxylic acid alkali salts
which is a first corrosion inhibiting component;
(c) 5 percent by volume of one or more emulsifying agents; and
(d) 61 to 71 percent by volume of water,
wherein a dilution of this metalworking fluid composition with water results
in an
opaque emulsion having a volume average particle size of 125 nm or greater
when diluted to 7.5 percent by volume.
[0013] Certain embodiments can be synthetic metalworking fluids that
demonstrate an engineered increase in lubricity while still providing
corrosion
protection and microbial control.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0014] [Not Applicable]
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DETAILED DESCRIPTION OF THE INVENTION
[0015] In an embodiment, the present metalworking lubricants
can have a
volume average particle size of 125 nm or greater when diluted between 0.1 and
50 percent by volume. In one embodiment, the compositions can comprise:
(a) one or more polymeric lubricity agents;
(b) one or more carboxylic acid salts;
(c) one or more emulsifying or dispersing agents; and
(d) a transport component.
[0016] More particularly, the compositions can comprise:
(a) 1 to 80 percent by volume of one or more block copolymers as the
polymeric lubricity agent;
(b) 1 to 40 percent by volume of one or more carboxylic acid salts;
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(c) 1 to 20 percent by volume of one or more emulsifying or dispersing
agents; and
(d) 1 to 97 percent by volume of a transport component.
[0017] In another embodiment, the compositions can comprise:
(a) 5 to 40 percent by volume of one or more block copolymers as
polymeric lubricity agents;
(b) 3 to 30 percent by volume of one or more carboxylic acid salts;
(c) 2 to 12 percent by volume of one or more emulsifying agents; and
(d) 18 to 90 percent by volume of a transport component.
[0018] In yet another embodiment, the compositions can comprise:
(a) 15 to 25 percent by volume one or more block copolymers as
polymeric lubricity agents;
(b) 5 to 15 percent by volume of one or more carboxylic acid salts;
(c) 3 to 8 percent by volume one or more emulsifying or dispersing
agents; and
(d) 52 to 77 percent by volume of a transport component.
[0019] Each component and examples of it is further described
below.
POLYMERIC LUBRICITY AGENTS
[0020] The polymeric lubricity agents can be, for example, EO/PO
copolymers. The EO/PO polymers can comprise, for example one or more of the
following. The EO/PO copolymers can be block copolymers having a central
polyoxypropylene block with a polyoxyethylene chain at either end. The EO/PO
copolymers can be block copolymers comprising a central polyoxyethylene block
with a polyoxypropylene chain at either end. The EO/PO copolymers can be
tetrablock copolymers derived from the sequential addition of ethylene oxide
and
propylene oxide to ethylenediamine. The EO/PO copolymers can be ethylene
oxide / propylene oxide copolymers having at least one terminal hydroxyl
group.
The EO/PO copolymers can be water-soluble lubricant base stocks of random
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copolymers of ethylene oxide and propylene oxide. The EO/PO copolymers can
be a water-soluble polyoxyethylene or polyoxypropylene alcohol or a water-
soluble carboxylic acid ester of such alcohol. The EO/PO copolymers can be
alcohol-started base stocks of all polyoxypropylene groups with one terminal
hydroxyl group. The EO/PO copolymers can be monobasic or dibasic acid
esters, polyol esters, polyalkylene glycol esters, polyalkylene glycols
grafted with
organic acids, phosphate esters,
polyisobutylenes, polyacrylon itri les,
polyacrylamides, polyvinylpyrrolidones, polyvinyl alcohols, or copolymers of
acrylic acid or methacrylic acid and an acrylic ester.
[0021] Specifically
contemplated polymers include a polypropylene glycol
block copolymer, a polyethylene glycol block copolymer, or a polyethylene
glycol/
polypropylene glycol block copolymer.
CARBOXYLIC ACID SALTS
[0022]
Partially neutralized carboxylic acid salts are contemplated to
provide a lipophilic moiety for the polymeric lubricity agents to network with
and
provide for the engineering of a larger particle size. The salts can be made,
for
example, by partial neutralization of free carboxylic acids, fats, or oils
using any
of the alkaline agents described in this specification. Specifically
contemplated
cations of the salts include alkali metal or alkanolamine salts, such as a
sodium
salt (made for example by treating an acid with sodium hydroxide). The pH of
the
partial neutralization is dependent upon the alkaline agent used. Many of
these
carboxylic acid salts additionally provide their own boundary lubrication as
well.
[0023] The
carboxylic acids used as feedstocks can be linear or branched,
saturated or unsaturated free carboxylic acids. The acids can be saturated or
unsaturated, and sites of unsaturation can be cis or trans configured. The
acids
can be dicarboxylic acids, tricarboxylic acids, or ester, amine, amide, or
ethoxylated derivatives of carboxylic acids. Alternatively, fats or oils of
animal or
vegetable origin can be neutralized directly to provide the carboxylic acid
salts.
[0024] The
following are some of the examples of contemplated carboxylic
acids or sources of same: caproic (also known as hexanoic) acid, enanthic
(also
known as heptanoic) acid, caprylic (also known as octanoic) acid, pelargonic
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(also known as nonanoic) acid, isononanoic acid, capric (also known as
decanoic) acid, neodecanoic acid, lauric (also known as dodecanoic) acid,
stearic
(also known as octadecanoic) acid, arachidic (also known as eicosanoic) acid,
palmitic (also known as hexadecanoic) acid, erucic acid, oleic acid,
arachidonic
acid, linoleic acid, linolenic acid, myristic (also known as tetradecanoic)
acid,
behenic (also known as docosanoic acid, alpha-linolenic acid, docosahexanoic
acid, ricinoleic acid, butyric acid, lard oil, tallow oil, butter, coconut
oil, palm oil,
cottonseed oil, wheat germ oil, soya oil, olive oil, corn oil, sunflower oil
and
rapeseed or canola oil.
EMULSIFYING OR DISPERSING AGENTS
[0025]
Diluting the metalworking fluid composition with water forms an
opaque emulsion. At a concentration above 10%, the emulsion may require
stabilization. Emulsifying or dispersing agents are contemplated to provide
stabilization of the engineered large particle emulsion.
[0026] The
emulsifying or dispersing agents may be one or more of the
following: alkanolamides, alkylaryl sulfonates, alkylaryl sulfonic acids,
amine
oxides, amide and amine soaps, block copolymers, carboxylated alcohols,
carboxylic acids or fatty acids, ethoxylated alcohols, ethoxylated
alkylphenols,
ethoxylated amines or amides, ethoxylated fatty acids, ethoxylated fatty
esters
and oils, ethoxylated phenols, fatty amines and esters, glycerol esters,
glycol
esters, imidazolines and imidazoline derivatives, lignin and lignin
derivatives,
maleic or succinic anhydrides, methyl esters, monoglycerides and derivatives,
naphthenic acids, olefin sulfonates, phosphate esters, polyalkylene glycols,
polyethylene glycols, polyols, polymeric (polysaccharides, acrylic acid,
acrylamide), propoxylated & ethoxylated fatty acids, alcohols or alkyl
phenols,
quaternary surfactants, sarcosine derivatives, soaps, sorbitan derivatives,
sucrose and glucose esters and derivatives, sulfates and sulfonates of oils
and
fatty acids, sulfates and sulfonates of ethoxylated alkylphenols, sulfates of
alcohols, ethoxylated alcohols, or fatty esters, sulfonates of dodecyl and
tridecylbenzenes, naphthalene, an alkyl naphthalene, or petroleum,
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sulfosuccinamates, sulfosuccinates and derivatives, or tridecyl and dodecyl
benzene sulfonic acids.
CORROSION INHIBITING COMPONENT
[0027] Oil-
containing products rely heavily on the oil itself to form a barrier
coating of corrosion protection. Non-oil-containing products optionally can
attain
this corrosion protection by chemical means. A corrosion inhibitor is a
chemical
compound that, when added in a small concentration, stops or slows down the
corrosion of metals and alloys.
[0028]
Some of the mechanisms for the corrosion inhibitors are the
formation of a passivation layer (a thin film on the surface of the material
that
stops access of the corrosive substance to the metal), inhibiting either the
oxidation or reduction part of the redox corrosion system (anodic and cathodic
inhibitors), or scavenging the dissolved oxygen.
[0029]
There are many different materials that fall into this group. Some
examples are alkali and alkanolamine salts of carboxylic acids, undecandioic
or
dodecanedioic acid or their salts, C4_22 carboxylic acids or their salts,
boric acid
and its salts, tolytriazole and its salts, benzotriazoles and their salts,
imidazolines
and their salts, alkanolamines and amides, sulfonates, alkali and alkanolamine
salts of naphthenic acids, phosphate ester amine salts, alkali nitrites,
alkali
carbonates, carboxylic acid derivatives, alkylsulfonamide carboxylic acids,
arylsulfonamide carboxylic acids, fatty sarkosides, phenoxy derivatives and
sodium molybdate.
ALKALINITY AGENTS
[0030]
Alkalinity agents provide for the desired pH of the product and, in
some cases for reserve alkalinity and pH buffering. Examples of the alkalinity
agents include but are not limited to alkanolamines - primary, secondary and
tertiary, aminomethylpropanol (AMP-95), diglycolamine
(DGA),
monoethanolamine (MEA), monoisopropanolamine (MIPA), butylethanolamine
(NBEA), dicylclohexylamine (DCHA), diethanolamine (DEA), butyldiethanolamine
(NBDEA), triethanolamine (TEA), metal alkali hydroxides, potassium hydroxide,
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sodium hydroxide, magnesium hydroxide, lithium hydroxide, metal carbonates
and bicarbonates, sodium carbonate, sodium bicarbonate, potassium carbonate
and potassium bicarbonate. A preferred alkalinity agent for certain
embodiments
is a metal alkali hydroxide.
[0031] The pH contemplated for the composition optionally is 3 or greater,
optionally from 3 to 10, optionally from 4 to 9, optionally from 4 to 8.
OTHER INGREDIENTS
[0032] The composition can also contain an anti-foaming agent and/or a
biocide or a fungicide, as well as any other conventional or novel additives.
TRANSPORT COMPONENT
[0033] The preferred transport component, which can also be referred to
as
the dispersion medium or vehicle, is largely, optionally entirely, water.
Optionally,
however, the composition may contain one or more oils, preferably at less than
10 percent by volume. These may be any conventional lubricating oils. An
emulsifier can be used to make a stable emulsion of the oil with water, if a
composite oil and water transport component is contemplated.
[0034] The positive attributes of currently available non-oil products
optionally
are maintained in this composition as well as optionally including one, more
than
one, or all of the following: environmental compliance, good cooling, good
chip
removal or settling characteristics, long sump life and good biological
resistance.
[0035] In the claimed invention, the working metal fluid composition,
when
diluted between 0.1 and 50 percent by volume can have a lubricity, measured by
tapping torque instruments, of less than 8000 N/cm.
[0036] The compositions may optionally have one or more of the
following
favorable properties in a low-oil (i.e. no more than 10% by volume oil) or an
essentially or entirely oil-free formulation:
= the lubricity of oil containing products,
= a lubricity/cost performance point approaching that of oil containing
products,
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= reduced worker irritation (irritation is associated with higher pH
products),
= the rust or other corrosion protection of oil containing products, or
= an alkanolamine free chemistry.
PARTICLE SIZE
[0037] The
present compositions as formulated contain particles, as will be
seen in the Examples below. Larger particles are contemplated to provide
greater lubricity, though the invention is not limited according to the
accuracy of
this theory. The contemplated particles of any embodiment optionally have a
volume average diameter of from 120 to 100,000 nanometers (nm), alternatively
from 120 to 100,000 nm, alternatively from 120 to 10,000 nm, alternatively
from
120 to 5000 nm, alternatively from 125 to 10,000 nm, alternatively from 125 to
5000 nmõ alternatively from 125 to 2000 nm, alternatively from 140 to 10,000
nm,
alternatively from 140 to 5000 nm, alternatively from 140 to 2000 nm,
alternatively from 200 to 10,000 nm, alternatively from 200 to 5,000 nm,
alternatively from 200 to 2000 nm, alternatively from 220 to 10,000 nm,
alternatively from 220 to 5,000 nm, alternatively from 220 to 2000 nm,
alternatively from 350 to 10,000 nm, alternatively from 350 to 5,000 nm,
alternatively from 350 to 2,000 nm.
EXAMPLES
[0038] The
foregoing may be better understood by reference to the
following examples, which are intended to illustrate methods for carrying out
the
invention and are not intended to limit the scope of the invention.
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EXAMPLE 1
Table 1
Material A
PluronicTM "R" block 0% 10% 20% 20% 20%
copolymer
Carboxylic acid - 10% 10% 10% 5% 0%
alkali salts
Emulsifiers 5% 5% 5% 5% 5%
Corrosion 4% 4% 4% 4% 4%
RO (reverse Remainder Remainder Remainder Remainder Remainder
osmosis) water
Lubricity ¨ E/A 6259 4285 3713 4233 5921
(N/cm)
Volume Average 120 140 350 220 20
Particle Size
(nanometers)
[0039] The materials A through E of Table 1 were employed in a tapping
torque operation involving the tapping of 6061 aluminum. The concentrates were
first diluted to a 7.5% by volume solution before testing. The tapping torque
test
is a quantitative measure of the lubricity performance of metalworking fluids.
It
has an ASTM standard method designation of D5619. Tapping torque reflects the
industrial machining process in a better way than other tests, which commonly
are carried out by rubbing two metal surfaces together. It is an excellent
method
of discriminating metalworking fluid (MWF) product machining performance in
the
laboratory. Tapping Torque results have been proven to correlate well with
field
machining performance.
[0040] The tapping torque instrument is designed to measure the lubricity
of
MWFs while actual cutting is performed. During the tapping operation, the
Tapping Torque instrument measures the instantaneous torque 250 times as
the tap advances throughout the depth of the cut. Specialized software then
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facilitates data analysis. Tapping torque is expressed in units of N-m (Newton-
meters) or N-cm (Newton-centimeters). Products with high lubricity will
generate
lower torque values. Conversely, low lubricity products will generate high
torque
values. In this way the instrument quantifies the differences in lubrication
performance between products.
[0041] One
drawback of the tapping torque instrument is in that the
absolute torque values measured are dependent upon and will vary with the
diameter of the tap used. Therefore, in order to cancel out these geometric
effects it is efficacious to express the lubricity as the torque per area to
describe
the energy it takes for a tap to make one revolution. The equation for this is
E/A = (2 'r) / r2
where t= torque value, r = the radius of the tap, E/A = energy per area and
the
units are N-m-1 (Newtons per meter) or N-cm-1 (Newtons per centimeter).
[0042] The
lubricity data is presented in Table 1, identified as E/A. The
lower the E/A value, the better the lubricity and machining performance. All
samples were diluted with water to 7.5% by volume before testing.
Example 2:
[0043] The
materials of Table 1 were employed in a particle size operation
involving the measurement of the volume average particle size in nanometer
units. The concentrates were first diluted with water to a 7.5% by volume
solution
before testing. The particle-sizing instrument uses high efficiency dynamic
light
scattering to quantify particle sizes of 20 to 100,000 nanometers.
[0044] All
samples were diluted to 7.5% by volume before testing. The
resulting particle sizes are shown in Table 1.
Example 3
[0045]
Material C from Table 1 was tested at two different concentrations
for particle size, and evaluated at each concentration for appearance and
emulsion stability. The
results are shown in Table 2, which shows a large
average particle size, opaque appearance, and excellent stability at each
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concentration. A larger particle size is characteristic of a better lubricant.
Typical synthetic MWFs, when diluted, form clear solutions with particle size
of
less than 100 nanometers. Dilutions of sample C have particle sizes 3.5 to 20
times larger than the maximum size seen with typical synthetic MWFs.
Table 2
Material Concentration Volume Appearance Emulsion
(by volume) Average Stability
Particle Size
(nanometers)
C from Example 1 7.5% 350 Milky white -Excellent
odaaue
C from Example 1 15.0% 2000 Milky white -Excellent
opaque
[0046] From examples 1-3 it is seen that optimal lubricity and particle
size is
obtained with sample C which combines 10% carboxylic acid - alkali salts and
20% PluronicTM "R" block copolymer. This ratio gives the maximum volume
average particle size and maximum lubricity.
[0047] It is also apparent from the examples that to a large degree,
the
lubricity of a composition is a function of its volume average particle size.
Increasing volume average particle size results in increased lubricity.
[0048] From example 3 it is seen that an increased concentration of
sample
C results in significantly larger volume average particle size. This explains
the
necessity of emulsifiers to stabilize higher concentrations of sample C.
Without
emulsifiers, it is believed that the particle size of higher concentrations
would
continue to agglomerate to an unstable state.
[0049] It should be understood that various changes and modifications
to
the presently preferred embodiments described herein will be apparent to those
skilled in the art.
