CA2005682A1

CA2005682A1 - Synthetic metalworking fluid

Info

Publication number: CA2005682A1
Application number: CA002005682A
Authority: CA
Inventors: Joann A. Quitmeyer
Original assignee: WR Grace and Co Conn
Current assignee: WR Grace and Co Conn
Priority date: 1988-12-21
Filing date: 1989-12-15
Publication date: 1990-06-21
Also published as: AU4713689A; EP0375412A1; JPH02225595A; AU628454B2

Abstract

ABSTRACT OF THE DISCLOSURE

A metalworking fluid comprising a polybutene and a polyether glycol. The metalworking fluid may or may not be diluted with water to form a micro-emulsion. The metalworking fluid provides excellent lubrication and cooling during the working of both hard and soft metals.

Description

~ 2 SYNTHETIC METALWORKING FLUI~
This application is a continuation-in-part of U.S.
Application Ser. No. 287,963, filed 12/21/88.
The present invention relates to metalworking fluids and more particularly a synthetic metalworking fluid which provides e~cellent lubrication and cooling for both hard and soft metals and is relatively bioresistant.

BACKGROUND CF THE INVENTIQN
In most industrial metal working operations, a metalworking fluid is employed. Metalworking fluids act both as a coolant to maintain the temperature of the metal surfaces within a desired range and as a lubricant to lubricate the interface of the tool and metal. The cooling effect of the metalworking fluid adds considerable life to the cutting tools, such as drill bits, metal formers, etc., and also tends to prevent the warping or distortion of the metal. The lubricating properties, on the other hand, reduce the friction between the cutting tool and the metal, thereby reducing the power requirement of the machinery.
There are four types of metalworking fluids: ¦
straight oils, soluble oils, semi-synthetics and synthetics.
Straight oils, which include mineral and vegetable oils, provide e~cellent lubricating properties but only minimal cooling. Soluble oils, i.e. emulsions of oil in water, provide both lubricity and cooling, and perform well on both hard metals, such as titanium and steel, and soft metals, such as aluminum. However, soluble oils are usually subject to rapid biodegradation and impaired lubricity after repeated use. Semi-synthetics, i.e. water solutions with smaller amounts oil microemulsified, and synthetics, i~C~

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non-petroleum based emulsions or solutions provide improved lubricity and cooling, can be filtered, and can generally be used for much longer periods of time than soluble oils.
However, neither synthetics nor semi-synthetics, free of chlorine, sul~ur or phosphorous, have been successfully used on difficult machining operations, e.g. tapping of both hard and sot metals. Prior art synthetics have used chlorine, sulfur or phosphorus as extreme pressure additives in order to machine hard metals. These additives create a hazard to the environment, and chlorine can cause hydrogen embrittlement (stress cracking). Also, when cutting differen~ metals it has been necessary to change metalworking fluids during the manufacturing process, increasing production time and causing disposal problems.
Soluble oils containing chlorine, sulfur or phosphorous extreme pressure additives have been used when a manufacturing process requires the working of two or more metals of significantly different hardnesses. However, soluble oils have several drawbacks. First, a single soluble oil may not be suitable for all metals in severe deformation processes such as tapping. Secondly, soluble oils have a ¦
typical useful life of 2-3 weeks, whereas synthetic fluids may be used for 12 months or more. Also, soluble oils present a disposal problem due to their petroleum base. If chlorine is present, an even greater disposal problem e~ists.
The present invention provides a synthetic fluid, free of chlorine, sulfur and phosphorous, without the shortcomings of soluble oils, wh;ch may be used as a metalworking fluid when working two or more metals of different hardnesses. The metalworking fluid of the present invention provides good lubrication and cooling t~ both hard and soft metals, allowing a ~ingle fluid to be used for both types of metal even in severe applications.

SUMMARY AND OBJECTS OF THE INVENTION
The present invention relates to a metalworking fluid containing a polybutene such as an isobutylene-butene copolymer or polyisobutylene; and a polyether glycol having a carbo~ylate functionality. In one preferred embodiment, the polybutene is a copolymer composed of 95-100% by weight mono-olefins and 0-5% by weight isoparaffins. The metalworking fluid may or may not be diluted with water to form a micro-emulsion.
It is an object of the present invention to provide a metalworking fluid comprisin~ an isobutylene-butene copolymer, composed of 95-100% by weight mono-olefins and 0-5~ by weight isoparaffins; a polyether glycol having a carboxylate functionality; and an emulsifier capa~le of forming a stable micro-emulsion.
Another object of the present invention is to provide a metalworking fluid comprised of an isobutylene-butene copolymer, a polyether glycol having a carbo~ylate functionality, a corrosion inhibitor and a defoamer.
A further object of the present invention is to provide a metalworking fluid that provides lubrication and cooling during the working of both hard and soft metals.
Yet another object of the present invention is to provide a metalworking fluid which prevents the buildup of residue on tooling and the metal being worked.

An additional object of the present invention is to provide a water dilutable, micro-emulsion metalworking fluid comprising from about 2 to about 50 parts by weight of an isobutylene-butene copolymer or polyisobutylene, and from about 2 to about 50 parts by weight of a polyether glycol having a carboxylate functionality.
An object of the present invention is to provide a metalwork;ng process comprising the steps of forming a metalworking fluid of an isobutylene-butene copolymer or polyisobutylene; and a polyether glycol having a carboxylate functionality, applying the metalworking fluid to a metal to be worked and working the metal.
Another object of the present invention is to provide a metalworking fluid comprised of a blend of an isobutylene-butene copolymer, or polyisobutylene, a polyether glycol having a carbo~ylate functionality and an emulsifier, the blend being diluted in a volume of water such that the blend comprises from about 0% to about 95% by volume of the total volume of blend and water.
An object of this invention is to provide a metalworking fluid comprising an emulsi iable blend of from about 2 to about 50 parts by weight of an isobutylene-butene copolymer, composed of about 95-100% by weight of one or more mono-olefins and about 0-5% by weight of one or more isoparaffins; from about ~ to about 50 parts by weight of a polyether glycol having a carbo~ylate functionality; and from about 5 to about 160 parts by weight of one or more emulsifiers.

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An additional object of the invention is to provide a metalworking fluid comprising from about 2 to about 50 parts by weight of a polybutene and from about 2 to about ~0 parts by weight of a polyether glycol having a carbosylate functionality.
These and other objects will be readily discernable to one skilled in the art from the following preferred embodiments and appended claims.

DETA~LED DESCRIPTION OF TH~ PREFERRED EMBODIMENTS
The present invention overcomes the shortcomings of prior metalworking fluids by providing a synthetic metalworking fluid which is useful in working both hard and soft metals.
The metalworking fluid of the present invention contains two major constituents, a polybutene selected from the group consisting of isobutylene-butene copolymers and polyisobutylenes~ to provide the lubricity needed for working soft metals, and a polyether glycol having a carboxylate functionality as an e~treme pressure additive for working hard metals. It has been found that this synergistic blend may be used to machine both hard and soft metals. The blend also une~pectedly provides lubricity superior to that obtained when polybutenes are used alone, and e~treme pressure properties superior to those obtained when polyether glycols are used alone. One or more emulsifiers may be added to the polybutene and the polyether glycol when the concentrate is to be emulsified in water. Other common metalworking fluid constituents may also be added, if desired.

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The fluid is made in concentrate (neat) form, i.e.
without the addition of water. The fluid may be used in its neat form or it may be diluted to a lesser concentration with water, if so desired.
The concentrate will preferably have a pH of from about 8 to about 10.5, more preferably from about 8.5 to about 9.5.
The isobutylene-butene copolymer used in one embodiment of the present invention is composed of about 95%
to 100% by weight mono-olefins and about 0% to 5% by weight isoparaffins. Mono-olefins are a class of unsaturated aliphatic hydrocarbons with one double bond, obtained by cracking petroleurn fractions at high temperatures.
Isoparaffins are a class of aliphatic hydrocarbons characterized by a straight or branched carbon chain, and have the generic formula CNH2n+2. Various grades of such a copolymer are commercially available from the Amoco Corporation and are sold under the tradename INDOPOL~. Any of these grades may be used in the present invention~ but preferably those with a viscosity less than 5000 SUS (measured at 100F).
One e~ample of a suitable isobutylene-butene copolymer has an average molecular weight of 563, a viscosity of 2441 SUS at 100F, and a flash point of 141C, and is sold under the tradename ~Amoco Polybutene H-15~. The amount of copolymer used in the present invention can range from about 1 part by weight to about 50 parts by weight. Preferably, the amount used is from about 2 parts by weight to about 36 parts by weight.

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The term polybutene refers to either a polyisobutylene which is essentially pure, or the isobutylene-butene copolymer described above which may contain up to about 5~ of other polymers, such as l-butene and 2-butene. The isobutylene-butene copolymer is preferred, as it is less susceptible to crystallization at low temperatures, but similar properties can be obtained using the 99+~
polyisobutylene. Mixtures of polyisobutylene and the isobutylene-butene copolymsr may also be used.
The isobutylene-butene copolymer, or polyisobutylene, is desired because it provides the lubricity ne~ded to obtain a good surface finish on soft metals such as aluminum.
The second constituent of the metalworking fluid is a polyether glycol having a carboxylate functionality. The polyether glycol having this structure provides additional lubricating properties to the metalworking fluid, and acts as an extreme pressure additive which reduces tool wear when machining hard metals such as titanium. Thus it is possible to machine hard metals without the use of traditional chlorine, sulfur or phosphorus e~treme pressure additives, eliminating the hydrogen embrittlement and disposal problems caused by these additives. Suitable polyether glycols are commercially available from the Olin Corporation~ under the trademark, POLY~G~.
One e~ample of a suitable polyether glycol is the proprietary polyoxyalkylene ylycol sold by Olin Corporation under the tradename POLY-G~ MLB-lOX~ This polyo2yalkylene glycol has a viscosity of 587 SUS (at 100F) and a specific gravity of 1.066 at 25C. The carbo~ylate functionality of this polyoxyalkylene glycol is acidic in nature.

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The amount of polyether glycol used in the present invention can range from about 2 parts by weight to about 50 parts by weight. Preferably, the amount used is from about 5 parts by weight to about 36 parts by weight.
A third constituent of the metalworking fluid, if desired, may be one or more emulsifiers. Any oil-in-water emulsifier may be used in the invention, alone or in combination with other emulsifiers.
Examples of suitable emulsifiers that may be used in the present invention include but are not limited to tall oil fatty acids, petroleum sulfonates, fatty acid amines, fatty acid alkanolamides and nonionic, cationic, anionic or amphoteric surfactants.
The selected emulsifiers should completely emulsify the other constituents of the concentrate when mixed with water. The emulsifiers should also be capahle of maintaining a stable emulsion during use.
The amount of emulsifier used in the concentrate is generally from about 5 parts b~ weiqht to about 160 parts by weight.
Other conventional metalworking fluid additives may be added so long as they do not adversely affect the emulsion stability or lubricity of the fluid. Such additives include corrosion inhibitors, defoamers, biocides, surfactants, azeotropes, colorants or dyes and pH buffering agents.
Examples of suitable corrosion inhibitors include, but are not limited to, amine carboxylates and amine borate esters. Other suitable corrosion inhibitors would be obvious to o ~killed in the a~t and a e conullercially a~ailable.

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The amount of corrosion inhibitor is generally from about .1 part by weight to about 20 parts by weight, and preferably from about .1 parts by weight to about 15 parts by weight in the concentrate.
Suitable defoamers may be used in the present invention. Such defoamers are generally proprietary products and are known only by their commercial trade names. Suitable, preferably organic, defoamers for use in the present invention include TROYKYD~ D666, a proprietary blend available from Troy Chemical, and Foam Ban MS-455 from Ultra Additives. Other suitable defoamers would be obvious to one skilled in the art.
The amount of defoamer is generally from about 0.25 parts by weight to about 10 parts by weight, and preferably from about 0.5 parts by weight to about 5 parts by weight.
The concentrate may be formed in any conventional manner such as 3dding all of the ingredients simultaneously and mixing them until a completely blended liquid is formed.
However, it is preferred to first add the isobutylene-butene copoly~er, or polyisobutylene, to a large mixer, then slowly add the one or more emulsifiers and then the corrosion inhibiting agent and polyether glycol, mi~ing well after each addition. Lastly, any other ingredients such as a defoamer and dye are added and thoroughly mi~ed into a homogeneous, stable blend. If desired, small amounts of water, may be added subsequent to mixin~. The concentrate is then decanted into containers for storage and shipment.
The metalworking fluid may be used in its neat form i.e., as a concentrate or it may be diluted.

j~ zoo~ z Preferably, the metalworking fluid is diluted with water such that the amount of concentrate is from about 1% to 50% by volume of the total volume of the water and concentrate. However, in applications where water cannot be tolerated, a 100~ solids concentrate can be used.
For example, where lubricity properties are most desired, less water is used so that there is more concentrate present. When cooling properties are most desired, the volume of water is greater than the volume of concentrate.
Generally, where lubricity is primarily required, the amount of water used is about 50% by total volume. Where cooling is primarily required, the amount of water is from about 80% to 99% by total volume.
The metalworking fluid is useful on a variety of metals including but not limited to steel, iron, aluminum, copper, titanium, nickel and alloys thereof.

A metalworking fluid concentrate of the following formula was mi~ed together:
4.5 parts by weight of an isobutylene-butene copol~ner;
- 6.0 parts by weight of a tall oil fatty acid low rosin emulsifier;
12.6 parts by weight of a petroleum sulfonate fatty acid amine blend emulsifier;

8.3 parts by weight of a fatty acid alkanolamide emulsifier;
7.5 parts by weight of polyoxyalkylene glycol, Olin Chemicals POLY-G~ MLB-lOX;

0.1 parts by weight of a surfactant, 1.5 parts by weight of an amine carboxylate corrosion inhibitor;
1.3 parts by weight of an amine borate ester corrosion inhibitor;
1.0 parts by weight of a sodium salt of tolyltriazole corrosion inhibitor;
0.2 parts by weight of a citrus fragrance;
1.5 parts by weight of a glycol ether;

3.0 parts by weight of a biocide;
0.5 parts by weight of triethanolamine;
0.5 part by weight of a defoamer, Troy Chemicals Troykyd~ D666; 0.5 of a second defoamer, Foam Ban MS-455 from Ultra Additives and, 0.06 part by weight of a blue dye.
51.0 deionized water (optional).
The fluid of E~ample 1 was used to machine hydraulic valve bodies from 2024 and 356 cast aluminums and titanium using a carbide tool. A straight oil was used side by side with the fluid of Example 1 for compar;son. Results were as follows:

Fluid of Coolan~ Typ~ ~traiqh~ Oil E~ample 1 Concentration 100~ 11% co~centration in water Sump Li f e 2 Months > 4 Months Parts/Tool Milling 500 1000+
Reaming 135 475+
Drilling 200 9oo+

Speed (SFM) Milling 60 600 Reaming 30 490 Drilling 100 600-800 Finish (RMS) Reaming 20-30 8-16 ~ 6~3~

The metalworking fluid of Example 1 was usable for more than twice as long as the straight oil. This is due both to the greater thermal stability of the fluid of Example 1 and to its reduced susceptibility to contamination by metal fines. The number of parts which could be machined with a given tool was greatly increased. Higher speeds were also obtainable and the surface finish was improved.
While this invention has been discussed in the light of its preferred embodiments, i,e. as a metalworking fluid for the cutting of hard and soft metals, it is by no means meant to be so limited. The metalworking fluid of this invention may be used in any metalworking operation where its properties would be useful. Examples of such metalworking operations include but are not limited to tapping, grinding, milling and forming.
Further, while this invention has been described with reference to its preferred embodiments, other embodiments can achieve the same results. Yariations and modifications of the present invention will be obvious to those skiiled in the art and it is intended to cover in the appended claims all such modifications and equivalents as fall within the true spirit and scope this invention.

Claims

1. A metalworking fluid comprising:
a) a polybutene and b) a polyether glycol having a carboxylate functionality.

2. The metalworking fluid of Claim 1 wherein the polybutene is an isobutylene-butene copolymer, composed of about 95-100% by weight of one or more mono-olefins and about 0-5% by weight of one or more isoparaffins.

3. The metalworking fluid of Claim 1 wherein the polybutene is essentially all polyisobutylene.

4. The metalworking fluid of Claim 1 wherein the polyether glycol is polyoxyalkylene glycol.

5. The metalworking fluid of Claim 4 wherein the polyoxyalkylene glycol has acidic carboxylic functionality.

6. The metalworking fluid of Claim 2 wherein the isobutylene-butene copolymer is from about 2 to about 50 parts by weight and the polyether glycol is from about 2 to about 50 parts by weight.

7. The metalworking fluid of Claim 6 further comprising from about 5 to about 160 parts by weight of one or more emulsifiers; from about 1 to about 20 parts by weight of one or more corrosion inhibitors; and from about 0.5 to about 15 parts by weight of a defoamer.

8. The metalworking fluid of Claim 7 wherein the emulsifier is selected from the group of sulfonates, nonionic, cationic, amphoteric or anionic surfactants.

9. A metalworking fluid comprising:
an emulsifiable blend of from about 2 to about 50 parts by weight of a polybutene; from about 2 to about 50 parts by weight of a polyether glycol having a carboxylate functionality; and from about 5 to about 160 parts by weight of one or more emulsifiers.

10. The metalworking fluid of Claim 9 wherein the polybutene is an isobutylene-butene copolymer, composed of about 95-100%5 by weight of one or more mono-olefins and from about 0-5% of one or more isoparaffins.

11. The metalworking fluid of Claim 9 wherein the polybutene is essentially all polyisobutylene.

12. The metalworking fluid of Claim 9 wherein the polyether glycol is polyoxyalkylene glycol.

13. The metalworking fluid of Claim 12 wherein the polyoxyalkylene glycol has acidic carboxylate functionality.

14. The metalworking fluid of Claim 9 further comprising from about 1 to about 20 parts of one or more corrosion inhibitors; and from about 0.5 to about 15 parts of an organic defoamer.

15. The metalworking fluid of Claim 9 further comprising the addition of water to the blend such that the water comprises from about 1% to about 99% by volume of the total volume of the blend and the water.

16. The metalworking fluid of Claim 9 wherein the emulsifier is a fatty acid alkanolamide.

17. A method of metalworking comprising the steps of:
a) applying to a metal surface a metalworking fluid composition comprising from about 2 to about 50 parts by weight of a polybutene and from about 2 to about 50 parts by weight of a polyether glycol having a carboxylate functionality; and b) performing a metalworking operation on the metal surface.

18. The method of Claim 17 wherein the polybutene is essentially all polyisobutene.

19. The method of Claim 17 wherein the polybutene is an isobutylene-butene copolymer, composed of about 95-100% by weight of one or more mono-olefins and about 0-5% by weight of one or more isoparaffins.

20. The method of Claim 17 wherein the polyether glycol is polyoxyalkylene glycol.

21. The method of Claim 20 wherein the polyoxyalkylene glycol has acidic carboxylate functionality.

22. The method of claim 17 wherein the metal surface is selected from the group consisting of steel, iron, aluminum, copper, titanium, nickel, and alloys thereof.

23. The method of Claim 17 wherein the metalworking fluid further comprises the addition of water such that the water comprises from about 1% to 99% by volume of the total volume of concentrate and water.

24. A metalworking fluid comprising:
a) a concentrate of an isobutylene-butene copolymer, composed of about 95% to 100% by weight of one or more mono-olefins and about 0%-5% of one or more isoparaffins; from about 5 to about 50 parts by weight of a polyether glycol; and from about 5 to about 60 parts of one or more emulsifiers;

b) a volume of water sufficient to form a micro-emulsion with the concentrate wherein the volume of concentrate is from about 1% to about 99% of the total volume of concentrate and water.

25. The metalworking fluid of Claim 24 wherein the emulsifier is a fatty acid alkanolamide, sulfonate blend, or nonionic, anionic, cationic or amphoteric surfactant or combination thereof.

26. The metalworking fluid of Claim 24 wherein the polyether glycol is polyoxyalkylene glycol.

27. The metalworking fluid of Claim 26 wherein the polyoxyalkylene glycol has acidic carboxylate functionality.

28. A metalworking fluid comprising:
a) from about 2 to about 50 parts by weight of a polybutene;
b) from about 2 to about 50 parts by weight of a polyether glycol having a carboxylate functionality; and c) from about 0 to about 99 parts by weight of water.

29. The metalworking fluid of Claim 28 wherein the polybutene is an isobutylene-butene copolymer and the polyether glycol is polyoxyalkylene glycol.

30. The metalworking fluid of Claim 28 further comprising the addition of water to the blend such that the water comprises from about 50% to 99% by volume of the total volume of concentrate and water.