CA1059111A

CA1059111A - Metal working lubricant comprising ethylene copolymers

Info

Publication number: CA1059111A
Application number: CA240,265A
Authority: CA
Inventors: Dominic A. Apikos; William W. Elliott
Original assignee: Atlantic Richfield Co
Current assignee: Atlantic Richfield Co
Priority date: 1974-12-20
Filing date: 1975-11-24
Publication date: 1979-07-24
Also published as: GB1525599A

Abstract

METAL WORKING LUBRICANT COMPRISING ETHYLENE COPOLYMERS
ABSTRACT OF DISCLOSURE
An improved method of lubricating a metallic component being worked involves the use of a composition comprising a major amount of oil of lubricating viscosity and a minor amount, sufficient to inhibit the liquid 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.

Description

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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--` lOS9111 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.

~059111 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.

-3-, lOS9~11 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 _~_ 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.

~5-1~59111 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.

-`` 1059111 (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 .

- lOS9111 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 __________________________________________________________ 2 1.88 3 2.60 __________________________________________________________

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.

- 1059~11 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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', 10 .' .

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a method for metal working wherein a lubricating amount of a fluid composition is maintained on the metal surface being worked, the improvement which comprises the step of main-taining on the metal surface being worked a liquid composition comprising a major amount of an oil of lubricating viscosity, and minor amounts of at least one non-crystalline, oil-soluble copolymer having a viscosity average molecular weight in the range from about 130,000 to about 250,000, said copolymer being derived from the polymerization of at least two olefins of differing molecular weights such that the lower molecular weight olefin is ethylene and the higher molecular weight olefin is selected from the group consisting of terminally unsaturated straight chain monolefins containing from 3 to 12 carbon atoms, .alpha.-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 mole ratio of said ethylene to said heavier olefin being in the range from about 1:3 to about 3:1, said copolymer being present in said fluid composition in an amount sufficient to inhibit said fluid composition from misting.

2. The method of claim 1 wherein said copolymer is present in an amount of at least about 0.001% by weight of the total composition.

3. The method of claim 2 wherein said heavier olefin is selected from the group consisting of terminally unsaturated straight chain monoolefins containing from 3 to about 12 carbon atoms and mixtures thereof.

4. The method of claim 3 wherein said copolymer has a viscosity average molecular weight in the range from about 150,000 to about 200,000.

5. The method of claim 3 wherein said copolymer is present in an amount from about 0.005% to about 0.5% by weight of the total composition.

6. The method of claim 5 wherein said heavier olefin is propylene.

7. The method of claim 6 wherein said copolymer is present in an amount from about 0.005% to about 0.5% by weight of the total composition.

8. The method of claim 7 wherein said copolymer has a viscosity average molecular weight in the range from about 150,000 to about 200,000.

9. The method of claim 8 wherein said copolymer is present in an amount from about 0.02% to about 0.4% by weight of the total composition.

10. The method of claim 9 wherein the mole ratio of ethylene to propylene in said copolymer is in the range from about 1:2 to about 2:1.