US3264218A - Corrosion inhibited antifreeze compositions - Google Patents

Description

United States Patent poration of Delaware N0 Drawing. Filed Mar. 26, 1963, Ser. No. 267,923 6 Claims. (Cl. 252-75) This application is a continuation-in-part of copending parent application Serial No. 120,158, filed June 28, 1961.

This invention pertains to novel corrosion inhibited antifreeze formulations and to aqueous solutions thereof. It particularly relates to an antifreeze which can be stored in metal containers, especially iron containers, for long periods of time at elevated temperatures without precipitates forming therein and without the container being attacked by the antifreeze to the extent the antifreeze leaks therefrom. The invention also concerns a method of producing the antifreeze formulations and their aqueous solutions. In addition the invention covers a method for-preventing corrosion of metals which come in contact with the antifreeze formulation.

The parent application describes antifreeze compositions of outstanding corrosion inhibiting effectiveness in aqueous heat exchange systems, such as the cooling system of an automobile. However, these described ant freeze compositions, as do many of the commercial antifreezes, in undiluted form are corrosive to their metal containers, such as steel cans and black iron drums, under storage conditions. The results of this attack after a period of time are leaks developing in the antifreeze container and precipitates forming in the antifreeze. Leaks are of course undesirable since antifreeze is lost and the salability of the packaged antifreeze becomes markedly reduced. Further, the precipitates formed in the antifreeze build up consumer sales resistance even though the precipitates may not affect the corros1on 1nhibiting properties of the antifreeze.

The storage deterioration is thought caused by the fact that when undiluted antifreeze is stored for long periods of time particularly under the elevated temperature conditions encountered in outdoor storage, the combination of freezing point depressant and inhibitors attacks the iron container. Specifically, it is believed the iron container is attacked by the antifreeze components to form ferric oxide. It is further believed the formed ferric oxide functions as a catalyst to accelerate the corrosion of the container. The results is pinhole leaks in the container and precipitates resulting from the reaction of iron with the various antifreeze components. By the term iron we also intend to include steel.

It is interesting to note that an antifreeze whlch may be satisfactorily corrosion inhibited under heat exchange conditions, such as in an automobile coollng system, may be unsatisfactorily inhibited for long term storage conditions since the conditions are essentially different. Further, under storage conditions even a minor amount of corrosion would cause puncturing of relatively thin container walls over a long period of time.

In the past, one method of preventing corrosive attack of undiluted antifreezes on their iron storage containers was to tin plate or coat said containers with an inert plastic material (polyethylene). Although the tin plated surface is resistant to antifreeze attack, the tin coatings were often damaged at the containers seams during the crimping and metal joining procesess, leaving portions of the underlying iron body exposed to attack. The coating of the inner surfaces of the steel containers with an organic plastic substance is highly effective in preventing corrosion. However, the plastic lining of containers is relatively expensive. In the highly competitive field of antifreeze any added cost is significant.

Accordingly, it is an object of this invention to provide an antifreeze formulation in concentrated (undiluted) form which can be stored in relatively inexpensive, unlined iron containers and tin plated containers for extended periods of time without leaking from said containers and without forming undesirable precipitation therein.

Another object of this invention is to produce an antifreeze formulation when in an aqueous system affords sunperior corrosion protection to metals normally found in heat exchange apparatus.

Still another object is to provide a method of forming the antifreeze compositions of the invention.

Further objects of the invention will become apparent from the remaining disclosure.

In accordance with this invention and the objects thereof, we have discovered that the incorporation of a combination of an alkanolamine and alkylenediamine tetra alkanoic acid or alkali metal salts thereof in the antifreeze compositions as described in Serial No. 120,- 158 results in a synergistic increase in the period of time that said compositions can be stored in iron or tinplated containers without undesirable precipitates forming therein and without the antifreeze leaking therefrom. The antifreeze compositions as disclosed in the parent application comprise a water soluble liquid alcohol freezing point depressant and a corrosion inhibiting agent comprising alkali metal tetraborate, alkaline earth metal tetraborate, alkali metal metaborate, alkaline earth metaborate, alkali metal mercaptobenzothiazole and an alkali metal arsenite. It is also taught therein that a separate oil phase may be optionally included with the antifreeze composition comprising a lubricating oil solution of a carbon dioxide neutralized basic alkaline earth metal sulfonate of a molecular weight between 900 and 1500. The addition of the sulfonate lube oil phase has been found to further increase the overall inhibiting action.

The freezing point depressants which may be utilized are any of the water soluble, water immiscible liquid alcohols, such as monohydroxy lower alkanols, and the liquid polyhydroxy alcohols such as the alkylene and dialkylene glycols. Specific examples of the alcohols contemplated are methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, diethylene glycol, propylene glycols, butylene glycols and mixtures thereof. A preferred alcohol is ethylene glycol and when sold commercially often contains a small amount, up to about 10% by weight, of diethylene glycol. The term ethylene glycol as used is to read either on the pure or commercial form. This is also true for the other freezing point depressant alcohols contemplated. The freezing point depressant advantageously comprises between about and 99 wt. percent, preferably between and 96 wt. percent, of the nonaqueous antifreeze, the remainder of the nonaqueous antifreeze being substantially the corrosion inhibiting agent and storage stability additive.

The corrosion inhibiting agent advantageously is present in the antifreeze compositions of the invention in an amount between about 1 and 9 wt. percent preferably between 2 and 4.5 Wt. percent, based on the weight of the water-soluble alcohol and preferably comprises between about 24 and 27 wt. percent alkali metal tetraborate, between about 36 and 45 wt. percent alkali metal metaborate, between about 4 and 5 wt. percent alkaline earth metal tetraborate, between about 6 and 10 wt. percent alkaline earth metal metaborate, between about 3 and 4 wt. percent alkali metal mercaptobenzothiazole and between about 13 and 22 wt. percent alkali metal arsenite. A preferred specific inhibitor combination is sodium tetraborate decahydrate (borax), sodium metaborate, calcium tetraborate, calcium metaborate, sodium mercaptobenzothiazole and sodium arsenite. Other examples of contemplated metaborates, tetraborates, arsenites and mercaptobenzothiazoles are potassium metaborate, potassium tetraborate, magnesium metaborate, magnesium tetraborate, barium tetraborate, potassium mercaptobenzothiazole, and potassium arsenite. We include within the definition of the metaand tetraborates the hydrous as well as the anhydrous forms thereof.

As heretofore stated, the parent application also encompasses a corrosion inhibiting oil phase in combination with the inhibited freezing point depressant. The added oil phase advantageously constitutes between about 0.5 to 2.5 vol. percent, preferably between 0.75 and 1.25 vol. percent, based on the volume of the freezing point depressant. The oil phase itself desirably comprises between about 0.5 and 5 wt. percent of an oil soluble CO neutralized alkaline earth (e.g., barium or calcium) metal hydrocarbon sulfonate having a molecular weight of between about 900 and 1500 and between about 95 and 99.5 wt. percent of a lubricating oil.

By the term CO neutralized basic alkaline earth metal hydrocarbon sulfonate it is intended to include approximately an equimole mixture of alkaline earth metal hydrocarbon sulfonate and alkaline earth metal c-arbonate, said mixture derived from the CO treatment of the product resulting from the reaction of a hydrocarbon sulfonic acid with approximately twice the stoichiometric amount of alkaline earth metal oxide (e.g., BaO, CaO) or hydroxide (e.g., Ba(OH) or Ca(OH) Examples of the sulfonic acids contemplated herein are the petroleum sulfonic acid, such as the mahogany sulfonic and green sulfonic acids. One particular suitable class of sulfonic acid is the alkaryl and dialkaryl sulfonic acids such as the alkylbenzene and dialkylbenzene sulfonic acids where the total number of alkyl carbons is in the 6 to 30 range. A specific example of a C0 neutralized sulfonate is a C0 neutralized basic barium alkylbenzene sulfonate having a molecular weight of between about 1100 and 1300, and a barium content of between about 21 and 25 wt. percent.

Specific examples of the lubricating oils contemplated in the oil phase are the paraffinic and naphthenic lubricating oils having a Saybolt Universal viscosity between about 50 and 100 at 100 F. and an API gravity between about 20 and 28.

A preferred oil phase consists of 2.5 wt. percent CO neutralized basic barium dialkylbenzene sulfonate having a molecular weight of about 1232 and a barium content of about 22.2 wt. percent and 97.5 wt. percent of a naphthenic lubricating oil having a gravity between 22 and 25 API, and a Saybolt Universal viscosity at 100 F. of between 70 and 75.

Water may be combined with the antifreeze compositions in any and all proportions to form the aqueous antifreeze solutions thereof. When the aqueous solutions of the antifreeze composition are to be used in cooling systems, the water miscible freezing point depressant should generally constitute at least about 10 vol. percent, preferably between about 20 and 60 vol. percent of the aqueous antifreeze solution. The corresponding water content, therefore, constitutes less than about 90 vol. percent, preferably between about 40 and 80 vol. percent of the aqueous antifreeze solution.

As heretofore stated, it has been found, and this constitutes an invention, that the combination of alkylenediamine tetraalkanoic acid or alkali metal salt thereof and an alkanolamine when incorporated in the above described antifreeze of the parent application synergistically increases the storage time of the aforedescribed antifreeze composition in respect to freedom from container leakage and precipitate formation and further substantially reduces the corrosiveness of the antifreeze to metals normally found in heat exchange systems such as brass,

copper, solder, steel, cast iron and aluminum.

The alkanolamines contemplated herein are of the formula:

(HOR) NH where R is an alkylene radical from 2 to 3 carbons and y is a whole integer from 1 to 3, inclusively. Specific examples of the alkanolamines contemplated herein are ethanolamine (EA), diethanolamine (DEA), triethanolamine (TEA), propanolamine (PA), dipropanolamine (DPA), and tripropanolamine (TPA).

In respect to the alkylene diamine tetraalkanoic acid, and salts thereof contemplated herein, they can be represented by the formula:

where R is an alkylene radical from 2 to 3 carbons, R is an alkylene radical from 1 to 3 carbons, and Z is a member selected from the group consisting of hydrogen, alkali metal and mixtures thereof. Specific examples of these salts contemplated herein are tetrasodium salt of ethylenediamine tetraacetic acid (tetra Na salt of EDTA), tetrasodium salt of propylenediamine tetrapropionic acid, ethylenediamine tetraacetic acid and dipotassium salt of ethylenediamine tetrapropionic acid.

Our storage stability additive combination is advantageously present in the contemplated inhibited antifreeze formulation in an amount between about 0.05 and 0.8 wt. percent, and in a weight ratio of alkanolamine to alkylenediarnine tetraalkanoic acid material of between about 1:1 and 1:2.

It is theorized that the combination of the amine alkanoic acid-salt and alkanolamine functions in the undiluted environment contemplated herein in reducing precipitates and container leakage by forming a complex with any reactive iron ions whether they be in the antifreeze solution or the wall of the iron container thereby preventing these ions from forming ferric oxide, the latter functioning as a catalyst for the further antifreeze attack on the iron containers. It is further theorized any ferric oxide that is formed is also comp-lexed by said combination thereby preventing the formed ferric oxide from acting as a catalyst for antifreeze deterioration of iron containers.

In the preparation of the antifreeze combinations of the subject invention, it is desirable to first make up a con centrate of the antifreeze for storage and/or transportation and prior to packaging antifreeze for retail distribution. The antifreeze concentrate can be subsequently diluted with additional freezing point depressants to bring the ingredient content to the desired level. A particular method is required for preparing the antifreeze formulation contemplated herein in order to prevent undesirable gelling and the formation of insoluble alkaline earth arsenites in the final antifreeze composition.

To between about and of the total amount of freezing point depressant to be used, there is added at a temperature between about 195 and 205 F. with agitation alkali metal tetraborate, boric acid, and an alkaline earth metal oxide. The agitation is continued and temperature maintained until solutioning of substantially all the ingredients occurs. The boric acid and alkaline earth metal oxide react to form a mixture of alkaline earth metal tetraborate and alkaline earth metal metaborate. At this point the reaction mixture is preferably filtered to remove any precipitate and the temperature reduced to between about and 180 F. To the thus cooled reaction mixture alkali metal mercaptobenzothiazole together with sodium hydroxide is added either as a solid or aqueous solution. Additional freezing point depressants may also be introduced at this point. The resultant mixture is stirred until solutioning of the additional ingredients occurs. The reduction of temperature at this point is required to prevent the decomposition of the alkali metal rnercaptobenzothiazole into dibenzyldisulfide. Dibenzyldisulfide is an insoluble precipitate and thereby eliminates mercaptobenzothiazole as an effective inhibitor. It is to be noted at this point the alkali metal hydroxide addition converts part of the alkali metal tetra'borate into alkali metal metaborate.

To the resultant solution the storage stability additive combination of an alkanolamine and the alkylenediamine tetraalkanoic acid material is added with agitation. The remaining freezing point depressant is then added at ambient temperature (e.g., about 98 F.) together with the alkali metal arsenite immediately after the stability additive addition or at a later period of time. Following this step the sulfonate oil, it to be employed, is added to the finished single-phase antifreeze solution at ambient temperature to form two-phase antifreeze.

Alternatively, the addition of the alkanolarnineamine alkanoic acid storage stability combination can be delayed to follow the addition of the arsenite or sul-fonate oil phase. The resultant singleand two-phase antifreezes are now ready for storage and/ or addition to water for use in heat exchange systems.

In the foregoing method, if the alkali metal arsenite is added prior to the addition of the remaining alcoholic freezing point depressant, an undesirable gel is formed together with an alkaline earth arsenite which is insoluble in the liquid freezing point depressant solution, both of which are difficult to redissolve.

The following examples serve to illustnate the invention but are not to be interpreted as limitations thereof:

EXAMPLE I This example illustrates the method of preparing the antifreeze combination of the invention.

' To 17,539 pounds of ethylene glycol maintained in agitation at a temperature of 200 F., there is added with stirring 3780 lbs. borax, 567 pounds b-oric acid, 227 lbs. lime. The resultant mixture is filtered and the filtrate is cooled to 150 F. and 760 lbs. of a filtered aqueous ethylene glycol solution of sodium mercaptobenzothiazole (water:ethylene glycol:rnercaptobenzoth-iazole weight ratio of 2: l: 1), 945 lbs. of a 50 wt. percent aqueous solution of sodium hydroxide, and 189 lbs. of water are mixed into the filtrate. The filtrate is cooled to 140 F. and there is added 190 Lbs. of triethanolam-ine and 190 lbs. of the tetrasodium salt of ethylenediamine tetraacetic acid with agitation to form a concentrate suitable for bulk shipment.

Subsequently, to 23,628 lbs. of concentrate, 162,994 lbs. of ethylene glycol and 1890 lbs. 'of a 50 wt. percent aqueous arsenite solution and 48 8 lbs. of water simultaneously is added with stirring at ambient temperature. The resultant undiluted antifreeze is of the following composition: 1'

Composition Percent by weight Ethylene glycol 95.30 Borax 0.80 Sodium metaborate 1.25 Calcium tetraborate 0.10 Calcium metabonate 0.25 Sodium mercaptobenzothiazole 0.10 Sodium arsenite 0.50 Triethanolarnine 0.10 Tetrasodium salt Ethylenediamine 0. 10 Tetraacidic acid Water 1.50

The water in the above composition is not an essential ingredient thereof and it is derived from the use of aqueous solutions, water of reaction, and from the additional water to facilitate the formation of the composition.

EXAMPLE 11 This example illustrates the preparation of a two-phase antifreeze.

To 189,000 lbs. of single-phase antifreeze prepared by the method of Example I, there is added 1,537 lbs. of an oil solution consisting of 2.5 wt. percent of CO neutralized basic barium dialkylbenzene sulfonate of a molecular weight of 1,232 having a barium content of 22.2 wt. percent and 97.5 wt. percent of a naphthenic lubricating oil of a gravity of 23 API and a Saybolt Universal viscosity at F. of 73. The resultant mixture forms two separate layers. The bottom layer 99 vol. percent of said mixture is the antifreeze of Example I. The remaining 1 vol. percent constituting the top layer is the sulfonate oil formulation described immediately above.

EXAMPLE III This example illustrates the corrosion inhibiting effectiveness of the antifreeze composition of the invention in a heat exchange system.

The corrosion test employed, and which is described directly below, simulates conditions under which corrosion of oxidizable metals is frequently encountered in a-utomotive engine systems containing anti-freeze coolants.

A clean, open-top, Pyrex glass cell is fitted with two air inlet tubes respectively connected to the bottom and the middle of the cell, both joining outside the cell to form a single inlet tube, and an air outlet tube connected to the upper side of the cell. One hundred fifty milliliters of a 25 wt. percent antifreeze solution in water is charged to the cell. The water used to dilute the antifreeze h as a 200 ppm. (by weight) chloride ion concentration. The air outlet tube is connected to a water cooled condenser and the joined inlet tubes are connected to a compressed air source. The open top of the cell is closed with a new rolled cork through which is passed a glass rod ending in a hook from which a bundle of test metal strip is suspended by the Nichrome wire. The test bundle comprises clean and weighed test metal strips of copper, brass, solder, cast iron, steel and cast aluminum having a known surface area. The test metal coupons are re movably mounted on a brass bolt and spaced with stainless steel washers. The bolt is tightened with a brass nut to hold the test metal strips rigid. This arrangement galvanically couples the individual metal strips to one another. The surface area of these test metals are in approximately the same relative proportions to one another as they would be in a representative automotive cooling system. The ratio of test metal surface area to coolant is also approximately the same as in the automotive cooling system.

The glass rod is adjusted so that the test bundle is immersed in the test solution. The glass cell is then placed in an oil bath maintained at a temperature of F. and air is bubbled into the test solution through the air inner tube at a rate of 50 milliliters per minute. The air was previously scrubbed free of any carbon dioxide by passing it through a 20 wt. percent aqueous solution of caustic. The cell is maintained in an oil bath for a period of 161 hours whereupon the test bundle is removed. Each test metal strip is freed of corrosion prod ucts by scrubbing with a household basic cleaner and a soft cloth and successively rinsed in distilled water and acetone. Each test metal strip is then dried and reweighed with the weight loss being calculated on the basis of milligrams lost per square decimeter of original surface area of the test metal strip (mg/sq. dm.).

Seven antifreeze compositions were subjected to the above test and were designated as Antifreeze A through G, in-clusively. Antifreeze A is an uninhibited ethylene glycol. Antifreeze B is an example of the antifreeze of the parent application. Antifreezes, C, D, E, and F are the same as Antifreeze B except they contain examples of one of the components of our storage stability combination. Antifreeze G represents the storage stabilized antifreeze combination of the invention.

The test data and results are reported below in Table I:

tion of the invention is subjected to the above described storage test. In addition, undiluted Antifreeze B containing one of the components of the storage stabilizing TABLE I A B C D E F G Comp. Antifreeze, Wt. Percent:

Ethylene Glycol 100 95. 50 95.40 95.00 94. 50 95.00 95.30 0.80 0. 80 0.80 0. 80 0. 80 O. 80 1. 25 1. 25 1. 25 1. 25 1. 25 1. 25 0.11 0. 11 0. 11 0. 11 0. 11 0. l1 0. 25 0. 25 0. 25 0. 25 0. 25 0. 25 0.10 0.10 0.10 0.10 0.10 0.10 0.50 0.50 0.50 0.50 0. 50 0.50 0.10 0.50 1.00 0.10 0.40 0. 10 Water 1. 49 1 49 1. 49 1 9 1.49 1. 49 Composition of Diluted Anti eeze,

Wt. Percent:

Water (200 p.p.n1. Cl 75 75 75 75 75 75 75 Antifreeze" 25 25 25 25 25 25 25 Corrosion Loss, mgJsq. dm.:

Brass 3 1 +1 +2 +3 +2 7 +2 +1 0 0 +2 0 56 20 20 1 71 31 2, 095 4 3 0 0 14 0 2, 210 +3 +2 4 169 +14 Cast Aluminum 20 239 150 88 110 652 164 As can be seen from the above, Antifreeze G, the representative of the antifreeze of our invention, gives essentially the same corrosion protection to brass, copper,

combination and undiluted Antifreeze B per se are testedfor comparison. The test data and results are reported below in Table II:

TABLE II.AI ITIFREEZE B WITH AND WITHOUT STABILITY ADDITIVE Storage Stabilizing Additive Cone. Days Before Precipitate Forms Additive, Weight Room 100 F. 120 F. 135 F. Percent Temp.

None Triethanolamine.--

TEA Na Salt of EDTA.--"

solder, steel and cast iron as Antifreeze B, which is identical to Antifreeze G except that it does not contain the novel storage increasing combination. However, in respect to aluminum, the antifreeze composition of the in-.

EXAMPLE IV This example illustrates the outstanding storage properties of the antifreeze formulation of the invention.

The storage test procedure is as follows:

A 4" strip of black iron out from a black iron drum is placed in a vertical position in a glass bottle. To the bottle there is added the antifreeze test solution in an amount to cover all but the top /2" of the test strip. The bottle is then stored under quiescent conditions and maintained at a constant temperature. The period of time in days it takes for a precipitate to form in the bottom of the bottle at a given temperature is recorded.

Undiluted Antifreeze B described in Table I containing an example-of the storage stability additive combina- Referring to the data in above Table II the outstanding storage stability properties of our additive combination can be seen. For example, at a storage temperature of 135 F. when no additive is present the period of stability is for only three days. When 0.2 wt. percent triethanolamine is added this is increased to fourteen days, 0.4 wt. percent triethanolamine increases it sixteen days, and 0.6 wt. percent triethanolamine further increases storage to twenty-one days. When the sodium salt of the ethylenediamine tetraacetic acid (Na salt of EDTA) is substituted for triethanolamine in an amount of 0.2 wt. percent, the storage stability is further increased to thirty-eight days, and the amount of 0.4 wt. percent sodium salt of EDTA still further increases storage stability to forty-three days. However, when the combination of triethanolamine and the sodium salt of EDTA is employed in an amount of 0.3 wt. percent each for a total additive amount of 0.6 wt. percent, the storage stability increases to days. In other words, our additive combination is over 4 times more effective than an equivalent amount of triethanolamine and 2 times more effective when almost an equal amount of sodium salt of EDTA is employed.

'In addition to the foregoing, a comparison of the data in Table I and Table II shows that there appears to be no correlation between the effectiveness of an alkanolamine and the alkylenediamine tetraalkanoic acid material in inhibiting corrosion in automotive cooling systems and the effectiveness of these same ingredients in prolonging the storage stability of antifreeze. For example, it is seen in Table I that the addition of triethanolamine substantially reduces corrosion while the addition of the sodium salt of EDTA substantially increases corrosion of cast iron and cast aluminum. Such data would indicate that the sodium salt of EDTA would be less effective as a storage stability additive than triethanolamine and in fact would promote storage instability. Contrary to such an assumption, it can be seen from Table II that the ethanolamine is less effective alone than said sodium salt alone in storage stability. Further an interaction takes place between the antifreeze ingredients and the container when both are in combination with the storage stability additive resulting in a synergistic increase in the storage stability of the antifreeze. The foregoing demonstrates the unexpected results of our storage stability additive combination in the contemplated antifreeze formulations.

We claim:

1. A storage stabilized antifreeze composition consisting essentially of a water soluble freezing point depressant alcohol, between about 1 and 9 wt. percent of an inhibitor combination and between about 0.05 and 0.8 Wt. percent of a storage stability additive, said combination consisting essentially of between about 24 and 27 wt. percent alkali metal tetraborate, between about 36 and 45 wt. percent alkali metal metaborate, between about 4 and 5 wt. percent alkaline earth tetraborate, between about 6 and 10 wt. percent alkaline earth metal metaborate, between about 13 and 22 wt. percent alkali metal arsenite and between 3 and 4 wt. percent alkali metal mercaptobenzothiazole, and said additive consisting essentially of an alkanolamine of the formula:

y is a whole integer from 1 to 3, inclusively, and an alkylenediamine tetraalkanoic acid material of the formula:

where R is an alkylene radical from 2 to 3 carbons, R is an alkylene radical from 1 to 3 carbons, and Z is a member selected from the group consisting of hydrogen, alkali metal and mixtures thereof, and said alkanolamine to said acid material being present in a weight ratio of between about 1:1 and 1:2.

2. A storage stabilized antifreeze composition in accordance with claim 1 wherein said combination also includes between about 0.5 and 2.5 vol. percent of an added oil phase inhibitor based on the volume of said depressant, said oil phase inhibitor consisting essentially of between about 95 and 99. 5 wt. percent lubricating oil and between about 0.5 and 5 wt. percent of a C0 neutralized basic alkaline earth metal hydrocarbon sulfonate and having a molecular weight between about 900 and 1500.

3. A storage stabilized antifreeze composition in accordance with claim 1 wherein said depressant is ethylene glycol, said alkali metal tetraborate is borax, said alkaline earth metal tetraborate is calcium tetraborate, said alkali metal metaborate is sodium metaborate, said alkaline earth metal metaborate is calcium metaborate, said alkali metal arsenite is sodium arsenite, said alkali metal mercaptobenzothiazole is sodium mercaptobenzothiazole, said alkanolamine is triethanolamine, and said alka'noic acid material is the tetrasodium salt of ethylenediamine tetraacetic acid.

4. A storage stabilized antifreeze composition in accordance with claim 2 wherein said depressant is ethylene glycol, said alkali metal tetraborate is borax, said alkaline earth metal tetraborate is calcium tetraborate, said alkali metal metaborate is sodium metaborate, said alkaline earth metal metaborate is calcium metaborate, said alkali metal arsenite is sodium arsenite, said alkali metal mercaptobenzothiazole is sodium mercaptobenzothiazole, said alkanolamine is triethanolamine, said alkanoic acid material is the tetrasodium salt of ethylenediamine tetraacetic acid, said oil is a naphthenic lubricating oil having a Saybolt Universal viscosity between 50 and 100 at 100 F. and an API gravity between 20 and 28 and said sulfonate is a C0 neutralized basic barium dialkylbenzene .sulfonate having a molecular weight between 1100 and 1300 and a barium content between 21 and 25 wt. percent based on said sulfonate,

5. An aqueous antifreeze composition consisting essentially of between about 40 and vol. percent water, between about 20 and 60 vol. percent water soluble freezing point depressant, said freezing point depressant containing between about 1 and 9 wt. percent of an inhibitor combination and between about 0.05 and 0.8 wt. percent of a storage stability additive, said inhibitor combination consisting essentially of between about 24 and 27 wt. percent alkali metal tetraborate, between about 36 and 45 wt. percent alkali metal metaborate, between about 4 and 5 wt. percent alkaline earth metal tetraborate, between about 6 and 10 wt. percent alkaline earth metal metaborate, between about 13 and 22 wt. percent alkali metal arsenite, between about 3 and 4 wt. percent alkali metal mercaptobenzothiaziole and said storage stability additive, consisting essentially of an alkanolamine of the formula:

where R is an alkylene radical having from 2 to 3 carbons and y is an integer from 1 to 3, .inclusively, and an alkylenediamine tetraalkanoic acid material of the formula:

where R is an alkylene radical of from 2 to 3 carbons, R is an alkylene radical from 1 to 3 carbons, and Z is a member selected from the group consisting of hydrogen, alkali metal, and mixtures thereof, the weight ratio of said alkanolamine to said material being between about 1: 1 and 1:2.

6. An aqueous antifreeze in accordance with claim 5 wherein there is also included between about 0.5 and 2.5 vol. percent oil phase inhibitor based on said freezing point depressant, said oil phase consisting essentially of between about and 99.5 wt. percent lubricating oil and between about 0.5 and 5 wt. percent of a C0 neutralized basic alkaline earth metal hydrocarbon sulfonate having a molecular weight between about 900 and 1500.

References Cited by the Examiner UNITED STATES PATENTS 2,126,173 8/1938 C-lapsadle et al. 25275 2,681,891 6/1954 Bos et a1 25275 2,803,603 8/1957 Meighen 25275 2,886,531 5/1959 Fiser 252-75 2,960,473 1 1/ 1960 Meighen et a1 252-75 3,079,343 2/ 1963 Bernard 252--75 ALBERT T. MEYERS, Primary Examiner.

JULIUS GREENWALD, Examiner.

I. D. WELSH, Assistant Examiner.

Claims (1)

1. A STORAGE STABILIZED ANTIFREEZE COMPOSITION CONSISTING ESSENTIALLY OF A WATER SOLUBLE FREEZING POINT DEPRESSANT ALCOHOL, BETWEEN ABOUT 1 AND 9 WT. PERCENT OF AN INHIBITOR COMBINATION AND BETWEEN ABOUT 0.05 AND 0.8 WT. PERCENT OF A STORAGE STABILITY ADDITIVE, SAID COMBINATION CONSISTING ESSENTIALLY OF BETWEEN ABOUT 24 AND 27 WT. PERCENT ALKALI METAL TETRABORATE, BETWEEN ABOUT 36 AND 45 WT. PERCENT ALKALI METAL METABORATE, BETWEEN ABOUT 4 AND 5 WT. PERCENT ALKALINE EARTH TETRABORATE, BETWEEN ABOUT 6 AND 10 WT. PERCENT ALKALINE EARTH METAL METABORATE, BETWEEN ABOUT 13 AND 22 WT. PERCENT ALKALI METAL ARSENITE AND BETWEEN 3 AND 4 WT. PERCENT ALKALI METAL MERCAPTOBENZOTHIAZOLE, AND SAID ADDITIVE CONSISTING ESSENTIALLY OF AN ALKANOLAMINE OF THE FORMULA: