Note: Descriptions are shown in the official language in which they were submitted.
1059111
This invention relates to an improved method ofmetal working. More particularly, it relates to an improved
method of metal working wherein a fluid, e.g., liquid,
composition used for lubrication in the metal working
operation is inhibited from misting.
In many metal working operations, it is conventional
to use a fluid, e.g., liquid, composition to lubricate the
metal surfaces being worked. One problem which may exist
in such operations is the misting of these liquid compositions.
Thus, the working of the metal may cause the liquid composition
to atomize into the air as a mist. This misting problem may
be so severe as to cause a significant loss of liquid
composition and, more importantly, may be a health hazard
to the personnel involved with the metal working operation.
United States Patent 3,805,918 discloses the use of polyolefins
having a viscosity average molecular weight of at least 5,000
as mist suppressants. However, it would be advantageous to
provide a further improved method of metal working wherein the
- liquid composition used for lubrication is inhibited from
misting.
~; Therefore, one of the objects of the present invention -
is to provide an improved method of lubrication.
Another object of the present invention is to provide
an improved method of metal working.
A still further object of the present invention is
to provide an improved method of metal working wherein a liquid
composition used to lubricate points of metal-to-metal contact
requiring lubrication is inhibited from misting. Other
objects and advantages of the present invention will become
apparent hereinafter.
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An improved method for lubricating a metallic
component being worked has now been discovered. It has now
been found that substantial benefits are achieved in a method
of metal working wherein a lubricating amount of liquid
composition, described hereinafter, is maintained (or caused
to be maintained) at the point or points of metal-to-metal
contact requiring lubrication. The liquid composition useful
in the present method comprises a major amount of oil of
lubricating viscosity and a minor amount, sufficient to inhibit
the li~uid composition from misting while in use, of at least
one oil-soluble ethylene copolymer having a viscosity average -
molecular weight in the range from about 130,000 to about
250,000, preferably from about 150,000 to about 200,000. This
ethylene copolymer, preferably substantially non-crystalline,
is derived from the polymerization of at least two olefins of
differing molecular weights such that the lighter olefin is
ethylene and the heavier olefin is selected from the group
consisting of terminally unsaturated straight chain monoolefins
containing from 3 to about 12 car~on atoms, ~-phenyl-l-alkenes
containing from 9 to about 10 carbon atoms, 2-norbornene,
terminally unsaturated non-conjugated di-olefins containing
from 5 to about 8 carbon atoms, dicyclopentadiene, 5-methylene-
2-norbornene, and mixtures thereof. The heavier olefin is pre-
ferably selected from the group consisting of terminally
unsaturated straight chain monoolefins containing from 3
to about 12 carbon atoms and mixtures thereof. More preferably,
the heavier olefin is propylene. The mole ratio of ethylene to
the heavier olefin in the copolymer is preferably in the range
from about 1:3 to about 3:1, more preferably from about 1:2
to about 2:1. Using this method, substantial and long lasting
mist inhibition, or suppression, of the liquid composition
is achieved.
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The copolymer in the liquid compositions useful in
the present methods is present in an amount sufficient to
inhibit the liquid composition from misting during use, e.g.,
in a metal working operation. Preferably, this copolymer is
present in the fluid composition in an amount of at least about
0.001~ by weight of the total composition. In order to
achieve maximum benefits of the present invention, it is more
preferred that the copolymer be present in an amount from about
0.005% to about 0.5% by weight of the total composition and most
preferred that the copolymer be present in an amount from about
0.02% to about 0.4% by weight of the total composition. In
many instances, the copolymer is available in the form of a
concentrate in a solvent, e.g., neutral lubricating oil.
The proportions given above refer to the amount of copolymer
and do not include such solvents.
; The copolymers useful in the present invention are
oil-soluble copolymers derived from ethylene and comonomers
; selected from the group consisting of terminally unsaturated
straight chain monoolefins containing from 3 to about 12 carbon
atoms; a-phenyl-l-alkenes containing from 9 to about 10 carbon
atoms; 2-norbornene; terminally unsaturated, non-conjugated
diolefins containing from 5 to about 8 carbon atoms; dicyclopen- -
tadiene; 5-methylene-2-norbornene; and mixtures thereof.
Suitable terminally unsaturated straight chain monoolefins -
containing from 3 to about 12 carbon atoms include propylene,
l-butene, l-pentene, l-hexene, l-heptene, l-octene, l-nonene,
l-decene and l-dodecene. Suitable a-phenyl-1-alkenes containing
from 9 to about 10 carbon atoms include 3-phenyl-1-propene and
4-phenyl-1-butene and the like. Suitable terminally unsaturated
non-conjugated diolefins containing from 5 to about 8 carbon
atoms include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene,
2-methyl-1, 5-hexadiene, 1,6-heptadiene and 1,7-octadiene and
the like.
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It is essential to the present invention that the
ethylene-containing copolymer have a viscosity average molecular
weight in the range from about 130,000 to about 250,000, prefer-
ably from about 150,000 to about 200,000. Copolymers having
viscosity average molecular weight less than about 130,000
have been found to provide inferior mist suppression. On the
other hand, copolymers having viscosity average molecular
weight in excess of about 250,000 become increasingly oil
insoluble and, therefore, become difficult to include in the
liquid lubricating compositions useful in the present invention.
The ethylene copolymers which are used herein may be
prepared by polymerization in the presence of coordination
catalysts using conventional techniques. Polymerization with
this type of catalyst is well known ~see, for example, U.S.
Patent Nos. 2,799,668, 2,933,480 and 2,975,159). For example
the use of a hydrocarbon-soluble vanadium compound, for example,
vanadium triacetylacetonate, in combination with an alkyl
aluminum chloride as described in U.S. Patent No. 3,300,459 and
in J. Polymer Science, 51, 411ff and 429ff (1961) is effective
to produce such copolymers. Use of this catalyst system results
in the formation of an essentially amorphous copolymer which
is soluble in neutral mineral oil. Since such copolymers exhibit
no substantial crystallinity as evidenced by x-ray examination,
a more precise measure of the amorphous character of the
polymer is the aforesaid solubility. The control of copolymer
molecular weight can be effected, for example, by the methods
disclosed in J. Polymer Science, 34, 531ff (1959), for example,
by the use of chain transfer agents such as metal alkyls,
especially zinc alkyls, or in United States Patent No.
3,051,690, for example, by the use of hydrogen.
Typical examples of the oils suitable for use in the
present invention are those which are conventionally used as
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lOS9111
lubricating oils. Although mineral oils are preferred, synthetic
oils may be used. Suitable oils include petroleum mineral
oils, such as refined coastal oils, refined mid-continent
oils, petroleum white oils and the like. The petroleum oils
may be refined by acid treatment, solvent extraction, hydrogenation
and/or other procedures in order to achieve the desired oil
quality. Although oils of widely varying viscosities can be
used in the products of the present invention, it is preferred
to use an oil with a viscosity of from about 50 SUS to about
2500 SUS at 100F., more preferably, from about 50 SUS to about
350 SUS at 100F. Combinations of two or more different oils
in a single lubricating composition are within the scope of
the present invention. The lubricating oil comprises a major
proportion, preferably, at least about 65%, more preferably at
least about 80%, by weight of the total composition.
The lubricating oil compositions contemplated herein
may contain other agents, such as ar.ti-wear agents, pour point
depressan~s, anti-foam agents, oiliness agents, blooming agents,
peptizing agents, anti-oxidants and the like. All of these
agents may be present in the compositions of the present invention
in amounts sufficient to achieve their individual functions.
The fluid compositions useful in the present invention
may be prepared in any conventional manner. For example, the
various components may be brought together and mixed at a
somewhat elevated temperature, e.g., from about 130F. to about
160F., to insure a uniform composition.
The liquid compositions useful in the present
invention can be employed by maintaining (ox causing to be
maintained) a lubricating amount of the composition on the metal
surface or surfaces being worked. These compositions can
be used in metal working operations such as cutting, grinding,
boring, broaching, milling, metal shaping, bending and the like.
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The copolymers useful in the present invention may
include minor amounts of polymerizable materials other than the
specified olefins. These materials may be present in these
inter-polymers in amounts which do not substantially detrimentally
effect the mist suppressing properties of the lubricating
compositions.
The following examples illustrate more clearly the
process of the present invention. However, these illustrations
are not to be interpreted as specific limitations on this
invention.
EXAMPLES 1 to 5
These examples illustrate certain of the outstanding
advantages of the present invention.
Four (4) compositions were prepared by blending
the components at a somewhat elevated temperature, e.g., 130F.
to 160F., to insure uniformity. The base oil composition
alone was tested ror comparative purposes.
COMPOSITION
Component, Wt.% 1 2 3 4 5
Base Oil (1) 100 98.5 98.5 98.0 98.0
Additive 1(2) - 1.5 - 2.0
Additive 2(3) - - 1.5 - 2.0
(1) The base oil is a commercially available
high severity mineral oil-based cutting oil
having a nominal viscosity of about 70 SUS
at 100F.
(2) A commercially available mist suppressant
containing about 8.0% by weight of an oil-solubl~,
substantially non-crystalline, ethylene-propylene
copolymer in neutral mineral oil. The proportion
of ethylene to propylene in the polymer was
determined to be about 3:2. The viscosity average
,molecular weight of this copolymer as determined
by gel permeation chromatography was 113,000.
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(3) A concentrate of about 8% by weight of an
oil substantially non-crystalline ethylene-
propylene copolymer in neutral mineral oil.
The proportion of ethylene to propylene in the
copoly~ler was determined to be about 3:2. The
viscosity average molecular weight as
., .
determined by gel permeation chromatography of
this ethylene-propylene copolymer was 166,000.
Each of these compositions were tested using the
following procedure. An apparatus was devised to aid in
determining the anti-misting properties of metal-working
compositions. The apparatus involved a reservoir for the
oil composition. ~he reservoir was heated in a water bath
to a temperature of 100F. The reservoir was closed and
air at 100F. and at a rate of 180 SCF/hr. caused to pass over
the top of a small diameter siphon tube immersed in the
oil and extending above the surface of the oil. In so doing,
the air picked up some of the oil composition. The air-
oil mixture was caused to flow from the horizontal, vertically
up through and then down a U-turn bend in one (1) inch copper
tubing. The air-oil mixture then flowed downwardly through
a 1-1/2 inch copper tube. At the bottom of this section, the
air-oil mixture flows upwardly at a 45 angle through a 3/4
inch copper tube. Finally, the air-oil mixture flowed
vertically downwardly through an ASTM reclassifier nozzle and
impinges upon a deflection plate which is located 1/2 inch from
the nozzle. The amount of oil leaving the reservoir was
determined by weighing the oil in the reservoir both before
and after the test. The oil which condensed in the lines, i.e.,
line condensate, was collected and weighed, as was the liquid
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oil which collected below the deflection plate, i.e.,
condensed mist. The amount of stray mist is determined by
difference, that is
Stray Mist = Oil Output from the Reservoir -
(Line Condensate + Collected Mist)
From these three measurements, a correlating parameter
called the "Mist Factor" can be determined. Thus, the "Mist
Factor" is defined as:
%Line Conde~sate X 100
`10 ~Output, gm./hr.) (~ Stray Mist)
It has been found that the Mist Factor is inversely proportional
to the tendency of a lubricant to mist. That is, the higher
the numerical value of the Mist Factor, the lower the misting
tendency of the lubricating composition.
Results obtained from testing each of these
compositions using the above-noted apparatus were as follows:
COMPOSITION MIST FACTOR
.
1 0.80
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2 1.88
3 2.60
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4 2.70
5 3.43
These examples show that the compositions useful
in the present invention, e.g., compositions 3 and 5,which
include ethylene-propylene copolymers having viscosity average
molecular weights in excess of about 130,000 have superior
mist suppressing properties relative to compositions which t
include lighter molecular weight polymers.
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While this invention has been described with
.~ respect to various specific examples and embodiments, it is
to be understood that the invention is not limited thereto and
that it can be variously practiced within the scope of the
following claims.
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