US3833502A - Method for improving the adherence of metalworking coolants to metal surfaces - Google Patents

Abstract

WATER-BASED, METALWORKING COOLANTS MAY BE MADE TO ADHERE TO METAL SUFACES BY INCORPORATING WITH SUCH COOLANTS SMALL AMOUNTS OF WATER-SOLUBLE POLYMERS.

Description

United States Patent O 3,833,502 METHOD FOR I1VIPROVING THE ADHERENCE F METALWORKING COOLANTS T0 METAL SURFACES Edward F. Leary, Western Springs, and Hobart Krrllic,

South Holland, 111., assignors to Nalco Chemical Coman Chicago Ill. i firawing. Tiled Apr. so, 1913, Ser. No. 355,375 Int. Cl. C10m 1/06 U.S. Cl. 252-49.5 3 Claims ABSTRACT OF THE DISCLOSURE Water-based, metalworking coolants may be made to adhere to metal surfaces by incorporating w1th such coolants small amounts of water-soluble polymers.

INTRODUCTION In the metalworking industry it is now a common practice to use a variety of metalworking coolants. These coolants function in two manners, namely to dissipate heat from the work surface and the tool, and to lubricate the interface between the work surface and the tool, thereby extending tool life and improving the general characteristicsof the finished workpiece. Metalworking coolants are used in a variety of metalworking and finishing operations which are normally performed on such typical machines as lathes, drill presses, automatic chuckers, milling machines, screw machines, grinders, saws, lapping machines and the like.

-In the past 20 years, great progress has been made 1n the development of improved metalworking coolants which are most frequently applied as water-based fluids.

Modern metalworking coolants may be generically catagorized as follows:

1. Synthetic Coolantsi.e., those that are water-soluble. These products are supplied in a concentrated form and are diluted with water when used in a machine tool.

I 2. Semi-Synthetic Coolantsi.e., those which contain ly results in clear product. These products are also supplied in a concentrated form to be diluted with water for machine operation.

3. Soluble Oil or Coolant-this type of product supplied as an oil with emulsifiers added. It is designed to be diluted with water when used in a machine tool. It forms a milky emulsion.

In addition to the above type coolants, there 1s a fourth type which is a straight oil type metalworking coolant or fluid, the use of which is not covered by the teachings of this invention. As can be seen from the above descriptions, all of the above metalworking coolants are d1- luted with water just prior to their use. Some of the ingredients are soluble in water whereas others of the ingredients are capable of being emulsified with water to form an oil-in-water emulsion which is then applied to the workpiece-tool interface.

' The application of these metalworking coolants is accomplished by taking a hoselike nozzle and applying a stream of the coolant directly to the area between the tool and the workpiece. As the metalworking coolant contacts the worksurface or the tool, one of which is usually "Ice moving in a rotational manner, the metalworking coolant tends to be thrown from the rotational workpiece or the tool which is being rotated due to the action of centrifugal force. This results in metalworking coolants being removed from the workpiece or tool in the form of fine droplets. Also, the metalworking coolant is frequently dissipated from the area to which it is applied due to the splash which occurs on the fluid contacting the surfaces to which it is applied. Due to the phenomenon of loss of metalworking fluid due to centrifugal force and splashes loss, substantial quantities of the fluid are lost into the atmosphere rather than being utilized in cooling and lubricating the tool and workpiece. In certain limited applications these fluids are applied in the form of fine mists which tend to dissipate into the atmosphere much of the fluid before it contacts the tool or workpiece.

If it were possible to treat metalworking fluids of the type described with a chemical composition which would allow the fluid upon contact with either the workpiece and/or the tool to be more firmly adhered thereto by the dimunition of the splash and centrifugal force effects, less fluid would be needed in metalworking operations of the type described. Such an additive should not only improve the losses occasioned by splashing and centrifugal force but it should not adversely alfect the cooling and lubricity factors of the metalworking fluid plus it should not affect their compatibility with water. If such an additive were available, an improvement in the art of metalworking would be afforded.

THE INVENTION In accordance with the invention it has been found that the capability of water dispersible metalworking coolants to adhere more tenaciously to metal surfaces to which they are applied may be afforded by adding to the aqueous phase of such coolants prior to their being applied to such metal surfaces at least five parts per million of a water-soluble polymer preferably the water-soluble polymer is formed by the polymerization of at least one monoolefinic compound through an aliphatic unsaturated group, said polymer having a molecular weight of at least 100,000.

THE WATER-SOLUBLE POLYMERS -As mentioned above, the polymers of the invention should have a molecular Weight in excess of 100,000. Greatly preferred polymeric additives have a molecular weight of at least 300,000. In many instances the molecular weight of the polymer additives ranges as high as ll0 million or more.

The preferred poymeric structures are derived by the polymerization of at least one mono-olefinic compound through an aliphatic unsaturated group to yield a waterdispersible synthetic polymer having a structure substantially free of cross-linkage. The polymer is therefore available for solubilization or sufficient dispersion in the particular metalworking fluid to be treated. Treating agents found to be especially effective for the purpose of the invention are water-dispersible synthetic polymers having a linear hydrocarbon structure and containing in a side chain, a hydrophilic group from the class consisting of carboxylic acid, carboxylic acid anhydride, carboxylic acid amide, hydroxy, pyridine, pyrrolidone, hydroxy alkyl ether, alkoxy, carboxylic acid salt groups, and mixtures of said groups.

Broadly speaking, the polymer treating agents which are'efiectiv'e fall into three classes; namely (1) those consisting of polymeric organic substances which in an aqueous medium will form organic anions having a substantial number of negative electrical charges distributed at a plurality of positions on the polymer; (2) those consisting of polymeric organic substances which in an aqueous medium will form organic cations having a substantial number of positive charges distributed at a plurality of positions on the polymer; and (3) those consisting of polymeric organic substances which in an aqueous medium will not form ions but nevertheless contain a suflicient number of hydrophilic groups to be water-dispersible. The first class of materials is referred to herein as anionic organic polymers, the second class is referred to herein as cationic organic polymers, and the third class is referred to herein as non-ionic organic polymers. The first two classes can also be referred to as polyelectrolytes.

The term polyelectrolyte is intended to cover synthetic organic polymers which in an aqueous medium will form organic ions having a substantial number of electrical charges distributed at a plurality of positions.

The synthetic organic polymers containing only carboxylic acid, carboxylic acid anhydride, and carboxylic acid salt groups in a side chain are anionic. The synthetic organic polymers containing only pyridine or other similar nitrogen-containing nuclei are cationic. The synthetic organic polymers containing only a carboxylic acid amide,

pyrrolidone, a hydroxy, a hydroxy alkyl ether and/or an 'alkoxy group in a side chain are non-ionic. The invention contemplates the employment of polymers which contain anionic, cationic and/or non-ionic groups. It also contemplates the employment of mixtures of anionic, cationic and/or non-ionic water-dispersible synthetic organic polymers.

The following synthetic organic polymers illustrate the types of polymers which have been found to be effective for the practice of the invention:

TABLE I Number Name 1 Polyacrylate Sodium Salt. 2 Polymethacrylic Acid Sodium Salt. 3 Maleic Anhydride-Vinyl Acetate Copolymer. 4 JPolyvinyl Methyl Ethermaleic Anhydride. 5 Methacrylic Acid-Acrylamide Copolymer. 6 Polyacrylic Acid. 7 Isopropenyl Acetate-Maleic Anhydride Sodium Salt Copolymer. 8 Itaconic Acid-Vinyl Acetate Copolymer. 9 Polyvinyl Pyridine-Hydrochloride. 10 ot-Methyl Styrene-Maleic Anhydride Sodium Salt Copolymer. 11 Polyvinyl Pyrrolidone. 12' Styrene-Maleic Anhydride Sodium Salt Copolymer. 13 Polyvinyl Alcohol. 14 Polyvinyl Methyl Ether. 15 MethylmethacrylicMaleic Anhydride Sodium Salt Copolymer. "16 Acrylic Acid-Styrene Copolymer.

*Any'of the polyelectrolytes disclosed in US. Pat. No.

2,625,529 can be employed for the purpose of the invention. 'When the copolymers are'identified in terms of their monomeric constituents, it should be understood that the names applied to these copolymers refer to the molecular structure and are not limited to the polymers prepared by the copolymerization of specific monomers. In many 4 I cases, the identical copolymers can be prepared from other monomers and converted by "subsequent chemical reaction to the desired copolymer.

Where the copolymer is derived from a polycarboxylic acid derivative and at least one other monomer copolymerizable therewith, the polycarboxylic acid derivative may be 'maleic anhydride, maleic acid, fumaric acid, itaconic acid, aconitic acid, citraconic acid, the amides of these acids, the alkali metal (e.g. sodium, potassium and lithium), the alkaline earth metal (e.g. magnesium, calcium, barium and strontium), and ammonium salts of these acids, the partial alkyl esters (e. g. methyl, ethyl, propyl, butyl, mono esters), the salts of said partial alkyl esters, and the substituted amides of thesepolycarboxylic acids. Where the hydrophilic maleic acid'derivatives are used as one of the starting components to form the copolymer, the hydrophobic comonomers may be, for example, styrene, alphamethylstyrene, vinyl toluene, chlorostyrene, vinyl acetate, vinyl chloride,-,viuyl formate, vinyl alkyl ethers, alkyl acrylates, alkyl methacrylates, ethylene, propylene, and/or isobutylene.

The foregoing synthetic .copolymers'are preferably ob tained by reacting equimolar proportions ofa polycarboxylic acid derivative and at least one other monomer. However, certain of the hydrophilic derivatives of unsaturated polycarboxylic acids can be polymerized in' less than equimolar proportions with some of the less hydrophobic comonomers, for example, vinyl formate and vinyl acetate.

In addition to homopolymers "and copolymers of any of the just mentioned monomers,combinations'thereof-or others, terpolymeric substances may likewise be'usually employed in reducing mist of sprayed herbicidal liquid concentrates. A greatly preferred group includespolymerized acrylamide as one of the components of either a copolymer or terpolymer. Usually the copolymer orterpolymer contains acrylamide as a major ingredient. Greatly preferred polymers include acrylamide-acrylic acid copolymers, and acrylamide-maleic"acid methacrylic terpolymers. V

In addition to the above described result's with'ca'tionic and anionic organic materials, highly desirable results have been obtained when high molecular weight ethylene oxide polymers are used. These polymers have a viscosity in centipoises at 25 C., of from 500 to 3 0,000 when made up in one-half to five percent aqueous solutions. For best results, such polymers should have moleculai' weights in excess of one million. The lower molecular weight materials have molecular weights starting at about 200,000. These polymers are prepared by heating appropriate quantities of ethylene oxide with initiating' moleculessuch as ethanol, ethylene glycol and the like in a sealed "tube for six hours or more in the presence of a catalyst. Suitable catalysts include alkaline earth metal carbonates such as strontium or calcium carbonate. While ethylene oxide condensate polymers are the most preferred materials, other non-ionic, polypolar polymers are not precluded from use in the invention. The expression polypolar polymers refers to polymers having a, plurality of nonionized groups whereby said polymers-are rendered hydrophilic. Such co'mpoundsfor use with this invention desirably include polyacrylamide, poly-substituted acrylthe metalworking fluid prior to their being applied to either a workpiece and/or the tool. Frequently in the case of high molecular weight polymers such as sodium polyacrylate this requires extremely long agitation periods to completely dissolve the polymer. This means that certain work schedules must be adjusted to allow for the time required to dissolve the polymer into the aqueous phase'of the metalworking coolants.

To allow more flexibility in preparation time for the addition of the polymers into the metalworking coolants, it has been found by us that a convenient method for rapidly dissolving these polymers is described in US. 3,624,019 the disclosure of which is incorporated herein by reference. In essence the teachings of the above patent indicate that if the water-soluble polymers of the type described above are first prepared in the form of a waterin-oil emulsion they may be rapidly dissolved in water by inverting these emulsions.

THE WATER-IN-OIL EMULSIONS The Water-in-oil emulsions described above may be prepared by any number of known techniques. The oils used in preparing these emulsions may be selected from a large group of organic liquids which include liquid hydrocarbons and substituted liquid hydrocarbons.

A preferred group of organic liquids are the hydrocarbon liquids which include both aromatic and aliphatic compounds. Thus, such organic hydrocarbon liquids as benzene, xylene, toluene, mineral oils, kerosenes, naphthas and, in certain instances, petrolatums may be used. A particularly useful oil from the standpoint of its physical and chemical properties is the branch-chain isoparafiinic solvent sold by Humble Oil & Refining Company under the trade name lsopar M. Typical specifications of this narrow-cut isoparaffinic solvent are set forth below in table H:

ulfur, p.p.m. Distillation, F.

IBP

ASTM D 1266.

ASTM D 86.

closed cup 1 Nephelometnc mud.

The amount of oil used in relation to the water to prepare the emulsion may be varied over wide ranges. As a general rule, the amount of oil-to-water may vary between 5:1-1:l0 with preferable emulsions being prepared in the ratio of 1:2 to 1:10. These ratios are illustrative of emulsions that can be prepared, although it should be understood that the invention is not limited thereby.

The emulsions may be prepared by any number of techniques. For example, the emulsions may be prepared by using high-speed agitation or ultrasonic techniques. In most instances, however, it is desirable that the emulsion be a stable emulsion and to achieve the end it is often necessary to employ an oil-soluble emulsifying agent. The amount of emulsifying agent to provide an emulsion will have to be determined by routine experimentation. As a general rule it may be said that the amount of oilsoluble emulsifier may range from 0.1 to 30 percent by weight based on the weight of the oil. To produce stable emulsions the amount of emulsifier will normally be Within the range of 12-20 percent by weight of the oil.

Rather than provide a listing of suitable emulsifiers, we prefer to generally recommend as being satisfactory the so-called low HLB materials which are well documented in the literature and are summarized in the Atlas HLB Surfactant Selector. Although these emulsifiers are useful in producing good water-in-oil emulsions, other surfactants may be used as long as they are capable of producing these emulsions. For instance, we have found that certain high HLB surfactants are capable of producing stable water-in-oil emulsions. A typical low HLB emulsifier is sorbitan monooleate.

DISPERSING THE POLYMERS INTO THE WATER-IN-OIL EMULSIONS In accordance with the first step or procedure, the water-soluble vinyl addition polymers or the gums are dispersed into the water-in-oil emulsion. The polymers as produced by most manufacturing processes are in the form of powders or lumplike agglomerates of varying particle size. It is desirable that the particles, before being placed into the emulsion, be cornminuted by grinding, abrading or the like so that their average particle size is less than 5 millimeters and preferably is within the range of l-5 microns. After the powders have been cornminuted, they may be dispersed into the water-in-oil emulsion by means of agitation provided by such devices as stirrers, shakers and the like. To be commercially practical, the amount of polymer in the emulsion should be at least 2 percent by weight. It is contemplated using emulsions containing between 5-75 percent by weight with preferred emulsions having a polymer concentration within the range of 10-45 percent by weight. In some cases the starting emulsions are converted to suspensions due to the nature and the amount of the polymer present therein.

From a commercial standpoint it is beneficial that the polymer emulsions thus described be stable, yet at the same time contain relatively large amounts of polymers. One method of insuring that the polymers do not precipitate when dispersed in the emulsion is that the particle size of the polymer be as small as possible. Thus polymers dispersed in the emulsifiers are quite stable when the particle size is within the range of 5 millimicrons up to about 5 microns. To produce particle sizes within these limitations, spray dryers with appropriate size nozzles may be used. It also is possible to prepare the polymer-containing emulsion of the water-soluble vinyl addition polymers directly from the vinyl monomers from which these polymers are synthesized. Such polymer-containing emulsion may be synthesized by using the Water-in-oil emulsion polymerization technique set forth in US. Pat. No. 3,284,393. The teachings of this patent comprise forming a water-in-oil emulsion of water-soluble ethylenic unsaturated monomers. The emulsion is formed by utilizing a water-in-oil emulsifying agent. To this monomer is added a free radical-type polymerization catalyst and then beat is applied under free radical-forming conditions to form water-soluble polymer latices. The polymeric latices produced by this patent are relatively unstable and frequently must be treated with additional emulsifiers to render the products stable.

INVERTING THE EMULSION When the polymer-containing emulsions of the type described are inverted in the presence of water, the polymer rapidly goes into solution. The polymer-containing emulsions release the polymer in the water in a very short period of time when compared to the amount of time required to dissolve a solid form of the polymer.

The polymer-containing emulsions may be inverted by any number of means. The most convenient means resides in the use of a surfactant added to either the polymercontaining emulsion or to the water into which it is to be dissolved. The placement of a surfactant into the water causes the emulsion to rapidly invert and release the polymer in the form of an aqueous solution. When this technique is used to invert the polymer-containing emulsion the amount of surfactant present in the water may vary over a range of 0.01 to 50 percent based on polymer. Good inversion often occurs within the range of 10-10 percent based on polymer.

7 THE SURFACTANTS The preferred surfactants are hydrophylic and are furalkyl or alkylene sulfonates, and sodium cetyl sulfonate,

sulfonated mineral oil, as Well as the ammonium salts thereof; and salts of higher means like lauryl amine hydrochloride, and stearyl amine hydrobrornide.

Any anionic, cationic, or nonionic compounds can be used as the surfactant. Examples of suitable surfactants are alkali metal, ammonium and amine soaps; the fatty acid part of such soaps contains preferably at least 16 carbon atoms because soaps based on lauric and myristic acids have a greater tendency to develop abundant foam.

Other examples of suitable anionic surfactants are alkali metal salts of alkyl-aryl sulfonic acids, sodium dialkyl sulfosuccinate, sulfated or sulfonated oils, e.g., sulfated castor oil; sulfonated tallow, and alkali salts of short chain petroleum sulfonic acids.

Examples of suitable cationic surfactants are salts of long-chain primary, secondary, or tertiary amines, such as oleylamine acetate, cetylamine acetate, di-dodecylamine lactate, the acetate of aminoethyl-aminoethyl stearamide, dilauroyl triethylene tetramine diacetate, l-aminoethyl-Z- heptadecenyl imidazoline acetate; and quaternary salts, such as cetylpyridinium bromide, hexadecyl ethyl morpholinium chloride, and diethyl di-dodecyl ammonium chloride.

Examples of suitable nonionic surfactants are condensation products of higher fatty alcohols with ethylene oxide, such as the reaction product of oleyl alcohol with 10 ethylene oxide units; condensation products of alkylphenols and ethylene oxide, such as the reaction products of isooctylphenol with 12 ethylene oxide units; condensation products of higher fatty acid amides with five, or more, ethylene oxide units; polyethylene glycol esters of long-chain fatty acids, such as tetraethylene glycol monopalmitate, hexaethyleneglycol monolaurate, nonaethyleneglycol monostearate, nonaethyleneglycol dioleate, tridecaethyleneglycol monoarachidate, tricosaethylene glycol monobehenate, tricosaethyleneglycol dibehenate, polyhydric alcohol partial higher fatty acids esters such as sorbitan tristearate, ethylene oxide condensation products of polyhydric alcohol partial higher fatty esters, and their inner anhydrides (mannitolanhydride, called Mannitan, and sorbitol-anhydride, called Sorbitan), such as glycerol monopalrnitate reacted with 10 molecules of ethylene oxide, pentaerythritolmonooleate reacted with 12 molecules of ethylene oxide, sorbitan monostearate reacted with 10 to 15 molecules of ethylene oxide; long-chain polyglycols in which one hydroxyl group is esterified with a higher fatty acid and the other hydroxyl group is esterified with a low molecular alcohol, such as methoxypolyethylene glycol 550 monostearate (550 meaning the average molecular weight of the polyglycol ether). A combination of two or more of these surfactants may be used, e.g. a cationic may be blended with a nonionic or an anionic with a nonionic.

Following is a list of suitable surfactants that could be used in the practice of this invention. Any water-soluble surfactant could be used, but naturally some are more efiicient than others. Useful surfactants include but are not limited to: polyoxyethylene alkyl phenol, polyoxyethylene (10 mole) cetyl ether, polyoxyethylene alkyl-aryl ether, poyoxyethylene monolaurate, polyoxyethylene vegetable oil, polyoxyethylene sorbit-anrmonolaurate, polyoxyethylene esters or mixed fatty and resin acids, polyoxyethylene sorbitol lanolin derivative, polyoxyethylene (12 mole) tridecylether, polyoxyethylene 'sorbitan esters of mixed fatty and resin acids, polyoxyethylene sorbitan-monostearate, polyoxyethylene sorbitan monooleat'e, polyoxyethylene monostearate, polyoxyethylene (20 mole) stearyl ether, polyoxyethylene (20 mole) oleyl ether, polyoxyethylene (15 mole) tridecyl ether, polyoxyethylene fatty alcohol, polyoxyethylene alkyl amine, polyoxyethylene .glycol monopalmitate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene (20 mole) cetyl ether, polyoxyethylene oxypropylene stearate, polyoxyethylene lauryl ether, polyoxyethylene lanolin derivative, sodium oleate, quaternary ammonium derivative, potassium oleate, N-cetyl N-ethyl morpholinium ethosulfate, and pure sodium lauryl sulfate.

In addition to using the water-soluble surfactants described above, other surfactants may be used such as silicones, clays and the like which are included as surfactants since, in certain instances, they tend to invert the emulsion even though they are not water-soluble.

In other specific cases the surfactant may be directly added to the polymer-containing emulsion; thereby rendering it self-inverting upon contact with water. These products, while capable of being used in certain systems, must be carefully formulated since the surfactants may tend to interact with the emulsifier or the emulsion and destroy it prior to its being used. I

Other techniques for inverting the emulsions include the use of agitation, high voltage electrical fields, heat and pH shift, as well as the placement into the water, into which the polymer-containing emulsion is to be dissolved, certain electrolytes. For any particular polymer-containing emulsion a suitable method for its inversion may be readily determined by routine experimentation.

ADDITION OF THE POLYMERS INTO THE METAL- WORKING COOLANT.

It is evident that all of the above polymers are watersoluble. They are most conveniently added to the aqueous phase of the metalworking coolants by first incorporating the polymers into the Water into which the metalworking lubricant is to be dissolved or emulsified to produce either an aqueous concentrate or to produce a level of coolant concentration suitable for application in metalworking operations of the type described. In certain instances the Water-soluble polymers or the water-in-oil emulsion form of the water-soluble polymers may be directly incorporated with the metalworking coolants which are normally provided as concentrates. In many instances, however, they are not compatible therewith and therefore, I the prior dilution of the water-soluble polymers into the water which is used to prepare the finished metalworking coolants provides a preferred mode of practicing the invention.

The amount of polymer needed to effectively improve the adhesive or cohesive characteristics of the metalworking fluids onto the workpiece or tool may vary from as little as 5 parts per million up to as much as 5001,000 parts per million. In the case of extremely high molecular weight polymers, care must be taken so that the-viscosity of the metalworking coolant does not increase to 'such a point that it becomes difiicult to work with and apply.

Depending upon the nature of the polymer,'its molecular configuration, molecular weight, etc, use dosages may 'be varied over a considerable range. It is preferred that the viscosity of the metalworking coolant not be increased more than 20 centipoises after addition of polymer; The dosages of polymer can be therefore adjusted within these limits. Excessive dosages of high molecular weight polymer have the tendency in most instances to increase the viscosity beyond the above stated range, and should be avoided. I

9 TYPICAL METALWORKIVNG COOLANTS Sy n the ti Coolants ,A typical synthetic coolant would: have-thefql ow ng t m m "T'IPIEORE'I'ICAL' SYNTHETIC FORMULA Alkali Soaps Coupling Agents (glycols, esters, ethers, etc.

as hexylene glycol, butyl carbotal, etc.)

Anti foam agents -2 Chelating agents 0-3 Rancidity Control Agents 0-2 Odor Masks 0-1 Dyes 0-1 Metal Deactivators 0-5 Corrosion Protectors 0-10 Coolants of this type as supplied by the manufacturer are in a concentrated form and are diluted with water at dilution factors ranging between -1 and 100-1 depending upon its ingredients, the nature of the particular metalworking operation and the like. A typical dilution would be one part of the above typical formula to forty parts of water.

'B. Soluble Oils.-A typical soluble oil used in metalworking industries would have the following formula:

THEORETICAL SOLUBLE OILS Percent Sulfur containing base (vegetable, animal or petroleum base) 025 Chlorine containing base (vegetable, animal or petroleum base) '025 Emulsifiers:

Will make anionic emulsifiers:

Amine 0 25 Fatty Acid n} Nonionic emulsifier Sulphonates (anionic emulsifier) Rosin Soaps (emulsifier) Sulfated Fatty Oils (emulsifier) Alkali Soaps (emulsifier) Coupling Agents Rancidity Control Agents (Dowicides,

etc.) 0*5 Anti Foam Agents 0-1 Chelating Agents (for hard water areas) 0-1 Solvent Oil (Kerosene, mineral seal oil,

paratfins, napthenic, etc.) 10-95 Odor Masks 0-1 Dyes 0-1 Metal Deactivators (prevent stain or attack on copper, brass etc.) 0-5 Corrosion Inhibitors 0-2 The above formula as in the case of the synthetic coolant would be diluted with about 40 parts of water to found to be successful using the teachings of the invention, Formulas C and D are presented below:

FORMULA C Percent Water 76.50 Polymer Emulsion* 0.60 Triethanolamine 12.80 Dodecyl Amine (Rx 10 Moles, etc. amine polyglycol) 1.00 Sodium Nitrate 2.40 Chlorinated phenols 0.30 Calcocid Blue Dye 0.005

FORMULA D Percent Paraflin Oil 76.47 Petroleum Sulphonate 6.60

Potassium salt of processed rosins and tall oils 12.10

*30% sodium polyacrylate in a water-in-oil emulsion which contlains a nonionie dispersant for purposes of inverting the emu S1011.

EVALUATION OF THE INVENTION To evaluate the invention the following test setup was used:

Example 1 Into a commercial lathe was chucked a three-inch diameter steel bar which was one foot long. The lathe was equipped with a supply hose for directing coolant onto the workpiece and the lathe cutting tool. The speed of the workpiece was set at 900 r.p.m. and the cutting tool set at a rake angle of 30 with the feed rate being relatively moderate. A coolant corresponding to Formula C without the water-soluble polymer present was diluted with forty parts of water. This formula was flooded onto the workpiece and tool during the cutting operation which lasted three minutes. A strobe light was set up and adjusted to allow visual observation of the droplet and splash patterns generated by the application of the coolant. It was observed that a substantial amount of liquid droplets were ejected from the rotating workpiece into the atmosphere.- A substantial amount of splashes could be observed at points contiguous to the area upon which the fluid was di-' rected. Using the same setup, Formula C was applied at the same dilution e.g. forty parts of water to one part of the formula and again visual observations were made using the strobe light. Splashing and coolant dissipation was reduced about percent.

Example 2 Using the same test method as described in Example 1, Formula D was tested both with and without the same water-soluble polymer present at 15 p.p.m. in the aqueous phase. Once again splashes and ejection of droplets into the air was reduced about 75 percent due to the presence of the polymer.

In both the above tests no difierence was observed in the degree of cutting etficiency or in the degree of cooling provided by the metalworking coolant formulas.

Having thus described our invention it is claimed as follows:

1. A method for improving the capability of water dispersible metalworking coolants to adhere to metal surfaces to which they are applied which comprises the steps of adding to the aqueous phase of said coolants prior to their being applied to a metal surface at least 5 p.p.m. of a readily inverted water-in-oil emulsion of a -1 l 1 2 water-soluble polymer having a molecular weight of at 3,624,019 11/ 1971v Anderson .;260+-2 9.6 H least 200,000, and then applying said metalworking cool- 3,298,954 1/1967 Brown 252 -495 X ants to a metal surface. 3,472,772 -10/1969 Chambers t' a1; "'252"=42.1 X 2. The method of Claim 1 where the water-soluble poly- 3,527,726 9/ 1970 Gower et al. 252- 493 X mer is a sodium polyacrylate. 3,556,996 1/1971 Joneset a1. -l--,. 252- 42.1 3. The method of Claim 1 where the sodium polyacrylate 5 3,563,895 2/ 1971 Janatka et a1 252-493 X is added to the aqueous phase of said metalworking cool- 3,629,112 12/ 1971 'Gower et al 252-42.1 X ant in the form of a water-in-oil emulsion which is then 3,657,123 4/1972 Stram 252-493 ,X inverted. 3,227,652 1/ 1966 Ackerman 2527,49,? X 1 References GOwer PATENTS 3,360,356 Vartlak 3,346,495 10/ 1967 Malec et a1 2524-9.3 H. M. S. SNEED, Primary Examiner 3,423,317 1/1969 Lubowitz et al. 252 -49.3 X v 7 3,432,434 3/1969 Armstrong et al. 25249.5 U.S. Cl. X R. 3,501,404 3/1970 Klaiber et al 25249.3 X 15 25242.1, v

3,725,274 4/1973 Orozco 25242.1 X

UNITED STATES PATENT OFHCE ECERTEFICATE OF CORREQTION Patent No. 3,833,502 Dated September 3, 1974 Inventor(s) EDWARD F, LEARY and HOBART M. KRILLIC It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 33, delete "of sprayed herbicidal liquid concentrates."

Column 7, line 19, after "suitable" add --anionic--.

Signed and sealed this 11th day of March 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C MASON Commissioner of Patents Attestlng Officer and Trademarks USCOMM'DC 6O375-P69 U.S, GOVERNMENT PRINTING OFFICE: I969 O-366-334 F ORM PO-IOSO (10-69)