MXPA98000296A - Useful life of refrigerant for prolonged engine through the stabilization of secondary silicate with polymarboxylate polimer - Google Patents

Abstract

The present invention relates to: providing corrosion inhibition formulations and compositions for inhibiting mineral oxide and corrosion of metals, particularly aluminum cavitation corrosion in the presence of aqueous liquids. The combination of a mixture of polymeric polycarboxylates, azoles, nitrate salts, phosphates, stabilized silicates and transition metal compounds provides a synergistic effect of corrosion protection of aluminum cavitation in aqueous liquids which reduces the corrosion rate and is effective at relatively low concentrations and several pH ranges. The addition of selected polymeric polycarboxylates does not significantly reduce cavitation erosion-cavitation of glycol-based refrigerants, aluminum corrosion that eliminates steam, and hard water and oxide precipitates, it has been found that polymeric polycarboxylates in combination with stabilized siloxane silicates improve the stabilization of secondary silicates leading to an improvement in aluminum corrosion protection and refrigerant life when used with selected quantities of the additives identified above. The formulations are particularly suitable for automotive applications

Description

USEFUL LIFE OF REFRIGERANT FOR PROLONGED ENGINE THROUGH THE STABILIZATION OF THE SECONDARY SILICATE WITH POLYCARBONYLATE POLYMERIC DESCRIPTION OF THE INVENTION This invention relates to an antifreeze formulation for inhibiting and preventing erosion and corrosion of aluminum and the corrosion of other metals exposed to an aqueous liquid in automotive refrigerant systems. The formulation also inhibits the oxidation of minerals. The novel antifreeze formulation comprises a mixture of polymeric polycarboxylates, azoles, nitrate salts, phosphates, silicates stabilized with siloxanes and transition metal compounds which provide a synergistic protective effect against cavitation corrosion of aluminum in aqueous liquids which reduce the Corrosion ratio and is effective in relatively low concentrations and several pH ranges. The addition of the selected polymeric polycarboxylates not only significantly reduces cavitation erosion-corrosion of glycol-based refrigerants, heat-removing aluminum corrosion, and hard water precipitates and oxide layer, it has been found that the polymeric polycarboxylates selected in combination with silicates stabilized with siloxanes improve the stabilization of secondary silicates leading to the improvement in aluminum corrosion protection and life of the refrigerant when used with selected quantities of the additives identified above. The formulations are particularly suitable for automotive applications. Antifreeze / refligerant technology traditionally uses silicate as a corrosion inhibitor. Silicates are particularly useful in the protection of components of the aluminum automotive cooling system. The silicate corrosion inhibitors generally use a phosphate, usually in the form of an alkali metal salt, to help protect the parts of the metal cooling system and also as a buffer to control the pH of the coolant. Frequently phosphate salts are used to help maintain a stable alkaline environment in which multiple corrosion inhibitors can function more effectively. The antifreeze / coolant is traditionally sold with a glycol content of almost 100 percent. This concentrated packaging allows flexibility so that the user can dilute antifreeze / coolant, as needed, with water available to obtain freeze / boil protection. However, corrosion protection over the full range of dilution is necessary.

In modern automotive engineering, many engine components are manufactured from aluminum. Engine coolants, mainly solutions based on propylene glycol and ethylene glycol, must transfer heat from which aluminum engines operate while inhibiting corrosion. Old motor vehicles do not have aluminum components and thus, Traditional antifreeze / coolant compositions can cause corrosion on components of aluminum or aluminum alloys that remove heat. Cavitation erosion-corrosion of aluminum water pumps after exposure to aqueous systems such as water-cooled internal combustion engine coolants is a relatively new development. U.S. Patent No. 4,548,787 describes the use of a combination of water-soluble phosphate with tunicate, selenate, and molybdate for protection against erosion-cavitation corrosion on aluminum. U.S. Patent No. 4,404,113 discloses the use of polyhydric alcohols as corrosion inhibition additives and cavitation reduction for refrigerants. Certain polycarboxylate type materials have been described for prevention of precipitates in antifreeze / coolant compositions. For example, U.S. Patent No. 3,663,448 describes the inhibition of rust by industrial cooling water using aminophosphonate and polyacrylic acid compounds, U.S. Patent No. 3,948,792 discloses an additive aqueous mixture to reduce and modify the amount of silicate oxide formed in automotive cooling systems. U.S. Patent No. 4,487,712 describes the use of polyacrylic acid as a silicate stabilizer to inhibit gelation which is a silicate depletion mechanism which can occur separately from hard water precipitates. The addition of polycarboxylates has been shown to significantly reduce cavitation erosion-corrosion of glycol-based coolants as indicated in U.S. Patent Nos. 5,288,419 and 5,290,469; to reduce corrosion of aluminum that eliminates heat as indicated in U.S. Patent Nos. 5,320,670 and 5,290,467; and to reduce precipitates of hard water and rust as indicated in U.S. Patent Nos. 5,330,670 and 5,290,468; all of which are incorporated here for reference. U.S. Patent No. 4,440,721, incorporated herein by reference, discloses the combination of water-soluble phosphate with a water-soluble molybdate, tungstate or selenate to provide an anti-cavitation corrosion effect of aluminum in aqueous liquids. . While alkali metal molybdates and soluble salts of tunisic and selenic acids have been used in anti-freeze compositions to prevent corrosion of metals, particularly molten iron, soluble salts of molybdic, tungstic and selenic acids act to retard corrosion of the aluminum, particularly erosion-corrosion cavitation of aluminum water pumps. None of the above references provides a means to obtain a long-life silicate-based antifreeze composition as is done in the present invention. The combination of selected polymeric polycarboxylates, azoles, nitrate salts, phosphates, stabilized silicates and transition metal compounds provide a synergistic protective effect against corrosion of aluminum cavitation in aqueous liquids that reduce the corrosion rate and is effective in concentrations relatively low and several pH ranges. The addition of the selected polymeric polycarboxylates not only significantly reduces erosion-corrosion of glycol-based coolant cavitation, heat-removing aluminum corrosion, and hard water and oxide precipitates, it has been found that the use of the selected polymeric polycarboxylates in combination with certain additives they improve the stabilization of secondary silicates, leading to an improvement in corrosion protection of the aluminum and life of the coolant. On the other hand, such formulation could be designed for cooling systems of passenger cars based on modern aluminum engines. The present invention has solved the need described above by providing an antifreeze / coolant composition utilizing the selected polymeric polycarboxylate additives which reduces corrosion over the full range of dilution without creating precipitates. This composition is soluble in water, alcohol, and alcohol / water mixtures, is compatible with other commonly used antifreeze / coolant components, does not corrode or damage automotive cooling systems and is effective at relatively low concentrations. In addition, the present corrosion inhibition formulations are effective in reducing corrosion in the total range of metals in the cooling system, including heat removal aluminum, aluminum alloys, copper, steel, cast iron, bronze, solder and the like. . It has been found that the water-soluble salts of an acid selected from the group consisting of molybdic, tungstic and selenic acids or salts thereof, in combination with a water-soluble phosphate and a polymeric polycarboxylate provide a synergistic improvement in the retardation of cavitation erosion-corrosion of aluminum water pumps and other metal motor components when used in conjunction with aqueous liquids, particularly aqueous antifreeze compositions containing a water-soluble alcohol freezing point depressant. It is an object of the present invention to provide corrosion inhibition formulations for antifreeze / coolant compositions with polymeric polycarboxylate additives selected to reduce erosion-cavitation corrosion of glycol-based coolants. Is Another object of the present invention to provide corrosion inhibition formulations for antifreeze / coolant compositions with polymeric additives selected to improve stability by providing an improvement in the life of the refrigerant. It is another object of the present invention to provide corrosion inhibition formulations which reduce corrosion over the entire dilution range of antifreeze / coolant compositions without creating precipitates. It is a further object of the present invention to provide corrosion inhibition formulations which are effective in reducing corrosion in the total metal range of cooling systems. It is a further object of the present invention to provide corrosion inhibition formulations which are effective in reducing corrosion in aluminum that eliminates heat. It is a further object of the present invention to provide corrosion inhibition formulations which are effective in reducing hard water and oxide precipitates. It is a further object of the present invention to provide corrosion inhibition formulations which are soluble in alcohol, alcohol / water mixtures and only water. It is an object of the present invention to provide corrosion inhibition formulations which are compatible with commonly used antifreeze / coolant components. It is another object of the present invention to provide corrosion inhibition formulations which are effective at relatively low concentrations. It is a further object of the present invention to use polymeric polycarboxylates in the corrosion inhibition formulations to reduce corrosion. These and other objects of the present invention will be more fully understood from the following description of the invention. A better understanding of the present invention will be had from the reference to the following description along with the accompanying drawings in which similar numbers refer to similar parts totally in the various views and where: Figure 1 is a graph showing the results of ALUMINUM CORROSION of Aluminum in Engine Dynamics Hour Solution for a solution of antifreeze without a polycarboxylate additive, with a GOOD-RITE '"polycarboxylate additive" "K-752, and with the polycarboxylate additive SOKALAN31 CP-12s : Figure 2 is a graph showing the EFFECT OF POLYCARBOXYLATE on the basis of the percentage of Silicon in the Motor Dynamometer Hours Solution for an antifreeze solution without a polycarboxylate additive and with a GOOD-RITE K-752 polycarboxylate additive. Figure 3 is a graph showing the EFFECT OF POLYCARBOXYLATE based on the percentage of Silicon in Solution against Hours of the Dynamometer of the engine by an antifreeze solution without a polycarboxylate additive and with a polycarboxylate additive SOKALAN0 CP-12s; and Figure 4 is a graph showing the EFFECT OF POLYCARBOXYLATE on the basis of the percentage of Silicon in the Engine Dynamometer Hours Solution for an antifreeze solution without a polycarboxylate additive, with a polycarboxylate additive GOOD-RITEF K-752, and with a SOKALAN® CP-12S polycarboxylate additive. The present invention provides antifreeze / coolant compositions for long life corrosion inhibition using certain polymeric polycarboxylate additives in a synergistic combination with stabilized silicate ("siloxane"), and other selected compounds which reduce erosion-corrosion of refrigerant cavitation , corrosion of aluminum that eliminates heat, and precipitates of hard water and rust. On the other hand, it has been discovered that polymeric polycarboxylates improve the stabilization of the secondary silicate leading to an improvement in aluminum corrosion protection and prolonged life of the coolant compared to conventional silicon based coolants. In addition, the corrosion inhibition formulations present are effective in reducing corrosion in the total range of metals in the cooling system, including aluminum that removes heat, aluminum alloys, copper, steel, cast iron, bronze, solder and the like. . This formulation is soluble in alcohol, alcohol / water mixtures and only water and exhibits excellent stability characteristics. The most preferred antifreeze / coolant composition is a type of silicate phosphate having a pH of about 10.5 and having about 94% antifreeze grade glycols and about 3% corrosion inhibitors, with the balance being water. The freezing point reducer used in the antifreeze compositions of the invention can be any of the suitable water-soluble liquid alcohols used hitherto in the formulation of antifreeze compositions. The water-soluble alcohol contains 1 to about 4 carbon atoms and 1 to about 3 hydroxy groups. Ethylene glycol is preferred as the freezing point reducer and especially commercially available mixtures containing a large amount of ethylene glycol and a small amount of diethylene glycol. The commercial mixture generally contains at least 85 to 95 weight percent of the ethylene glycol with the residue being diethylene glycol and small amounts of substances which are incidentally present such as water. Another liquid alcohol soluble in water can be mixed with ethylene glycol but such mixtures are usually not preferred. Commercially available inexpensive water soluble alcohols can also be used such as methyl, ethyl, propyl and isopropyl alcohol alone or in combination. The concentrated corrosion inhibiting formulations of the present invention is a water-based mixture of polymeric polycarboxylates, nitrate salts, phosphate, azoles, stabilized silicates and transition metal compounds. Optionally, other components including defoamers, dyes, isolation agents, biocides, and the like can be added to the present formulation. Although a water-soluble phosphate level is given on the basis of acid phosphate, alkali metal salts are typically used. Alkali or ammonium earth salts are also possible alone or in combination between them. Nitrate is typically introduced as an alkaline salt although salts of acids, alkaline earths or ammonium can be used including potassium, sodium or salts alone or in combinations with them. Azoles include tolitriazole, benzotriazole, mercaptobenzotriazole including mixtures and other substituted azoles. Stabilized silicate, typically referred to as a siloxane compound, are of the type described in U.S. Patent Nos. 4,5354,002, No. 4,362,644, and / or 4, 370,255, incorporated herein for reference. Suitable defoamers include PLURONIC® L-61, PATCOTE® 415 and other surfactants including silicone type. The synergistic combination of phosphate, molybdate and stabilized silicate is described in US Pat. Nos. 4,548,787, No. 4,707,286, and No. 4,440,721, incorporated herein by reference. It is contemplated that in addition to the silicate-phosphate type coolants, these additives are useful in silicate-borax, silicate-phosphate and borax refrigerants, organic acid type coolants, and organic-silicate acid hybrids, and the like. The corrosion inhibiting formulations are compatible with other commonly used antifreeze / coolant components and are effective at relatively low concentrations. Each of the preferred ingredients of the synergistic formulation of antifreeze, either mandatory or optional, are discussed below: PO ICARBOXIT..ATOS The preferred class of stabilizing polymer polycarboxylates is based on polyacrylic acid (PAA) and / or polymaleic acid (PMA). These polymeric polycarboxylates are compatible with other components in the typical antifreeze / coolant composition, and do not exhibit additional toxicity or disposal problems. The molecular weight distribution of useful materials can average about one hundred grams / mol to about three million grams / mol. Chemically, the materials should be based on polymers or copolymers of acrylic acid and / or maleic acid, including any modifiers, such as alcohols. The polycarboxylates used in the present invention have a molecular weight in the range of about 1,200 to about 250,000, with a preferred range of 500 to 12,000. More specifically, the most preferred additives have average molecular weights in the range of about 500 'to about 4,000 and more specifically about 1300 to about 1800 and about 300 to about 4600.

When referring to polycarboxylates within the context of the present invention it is understood that it embraces those water soluble copolymers and homopolymers having at least one monomeric unit containing C3_6 monoethylenically unsaturated mono or dicarboxylic acids or their salts. Suitable monocarboxylic acids of this type are, for example, acrylic acid, methacrylic acid, ethacrylic acid, vinylacetic acid, allylacetic acid, and crotonic acid. The preferred monocarboxylic acids of this group are acrylic acid and methacrylic acid. An additional component of the polycarboxylates comprises C4.6 monoethylenically unsaturated dicarboxylic acids, for example, maleic acid, itaconic acid, citraconic acid, mesaconic acid, fumaric acid, or methylenemalonic acid. The preferred acid is maleic acid. Other organic substituents can be used as comonomers or as aggregate modifiers along the polymer chain. Examples of such are shown as Formula I H R I I c-c (I) I 1 H X n Where R = H or a secondary alcohol such as isopropanol, X = COOH, COO-Na +, Methyl vinyl ether, isobutylene, vinyl acetate, acrylamide, or styrene, with the proviso that when R = a secondary alcohol, X = COOH or COO -Na +, and when X = to any other group mentioned above, R = H. Preferred polycarboxylates are a copolymer of acrylic acid and maleic acid, or its sodium salts, the copolymer having a molecular weight of 3000, and a sodium salt of the polyacrylic acid modified with a secondary alcohol such as isopropanol, the polymer having a molecular weight of 4000. The polycarboxylates used in the present invention are obtained by methods well known to those skilled in the art. The general method of synthesis is via polymerization of free acid radicals. The polymerization can be carried out in an aqueous medium, in the presence of polymerization initiators, with or without regulators. Polymerization can take several forms; for example, the monomers can be polymerized in a batch form in the form of aqueous solutions. It is also possible to introduce in the polymerization reactor a portion of the monomers and a portion of the initiator, heat the mixture in an inert atmosphere at the polymerization temperature and then add the remaining monomers and the initiator to the reactor in the polymerization ratio. The polymerization temperatures are in the range of 20 ° C to 200 ° C. Temperatures above 100 ° C are used in pressure vessels. The carboxyl-containing monomers can be polymerized in the free carboxylic acid form, in the form of partially neutralized, or completely neutralized. The neutralization is preferably carried out with an alkali or ammonium metal base. The polymerization initiators used are preferably water-soluble free radical formers such as hydrogen peroxide, peroxodisulfates and mixtures of the two. The polymerization can also be initiated with water-insoluble initiators such as dibenzoyl peroxide, dilauryl peroxide, or azodiisobutyronitrile. The polymerization can be carried out in the presence of regulators. Examples of such regulators include water soluble mercaptans, ammonium formate, and hydroxylammonium sulfate. The polymeric polycarboxylate materials which are useful in the present invention include CIBABelclene water treatment additives. GEIGY®, colloidal additives from COLLOIDS®, Inc., GOOD-RITE® polyacrylates, and CARBOPOL® resins from BF GOODRICH® and the like. Examples of polycarboxylates which can be used in the present invention are those sold by BASF® under the usual name of SOKALAN® polycarboxylates, which are available in aqueous polymer solutions. More particularly, SOKALAN polyacrylic dispersants are dispersants of the carboxylate copolymer. These SOKALAN® polycarboxylates are acrylic / maleic copolymers and other copolymers, either maleic or acrylic acid. These polycarboxylates are generally completely neutralized. The suffix "S", is a designation used to indicate free acids in the SOKALAN® range. While particularly preferred additives, SOKALAN® CP10, CPlOs, or CP12s, have been shown to be particularly effective at about 0.05 to about 0.20 weight percent in an inhibitor concentrate, other levels of additives and different polycarboxylates may also be used. SOKALAN® 10 has an advantage relative to the molecular weight of about 4,000, and comprises polyacrylic acids modified with secondary alcohols; while SOKALAN® 12 has an advantage relative to the molecular weight of about 3,000 and comprises a sodium salt of a copolymer of acrylic acid and maleic acid. The polymeric polycarboxylate is preferably present in the formulation in an amount of about 0.001 to about 10.0 percent by weight, and more preferably in an amount of about 0.01 to about 0.1 percent by weight. The preferred polycarboxylate is effective to improve stability at relatively low concentrations, generally about 100 to about 1000 ppm per total volume of the inhibition concentrate.

The most preferred polycarboxylates are the polyacrylate polymers K-700 from BF GOODRICH® which include the polyacrylate polymers GOOD-RITE® K-732 and GOOD-RITE® K-752. Both are mixtures of sodium polyacrylate and polyacrylic acid in water as indicated and described in copies of Material Safety Data documents as indicated in the Information Disclosure Document and are incorporated herein for reference. These polymers are similar, while differing by their molecular weight. GOOD-RITE® polyacrylate K-752 is a water-soluble acrylic acid polymer supplied as clear to hazy, colorless to amber, and in the range of about 62% to about 64% total solids solution in water in a average of approximately 63%, with the active solids that are approximately 62.5% having a specific gravity of approximately 1.23. The molecular weight (GPC M is approximately 2100. The pH ranges from about 2.2 to 3.0 and average about 2.6.The viscosity ranges (CP at 25 ° C) of between about 400 to about 1,400, and average about 950. GOOD-RITE® polyacrylate K-752 is a water-soluble acrylic acid polymer supplied as clear to hazy, colorless to amber, and in the range of about 49% to about 51% total solids solution in water in a average of approximately 50%, with the active solids being approximately 49.5% having a specific gravity of about 1.2.The molecular weight (GPC MJ is approximately 5,100 .The pH ranges from approximately 2.2 to 3.0 and average of approximately 2.6. of viscosity (CP at 25 ° C) of between about 250 to about 500, and average of about 350. The combinations of the polycarboxylates can also be used in the pres an invention such as a mixture of a modified polyacrylic acid with secondary alcohol, a sodium salt of a copolymer of acrylic acid and maleic acid and / or mixtures of sodium polyacrylate and polyacrylic acid in water. These combinations having a molecular weight of less than 10,000 are considered to be suitable polycarboxylate additives. CORROSION SALT (Nitrate) INHIBITORS Where aqueous liquids make contact with other metals besides aluminum, including aluminum water pumps, corrosion inhibitors of metal salts, preferably alkali metal salts known in the prior art can be usefully added to aqueous liquids or the invention. Such corrosion inhibitors include nitrates, nitrites, silicates, carbonates, sodium silicate, sodium nitrate, potassium carbonate, water soluble ammonium silicate.

Preferably, a nitrate is used in the preferred composition. The source of the nitrate ion can be any water-soluble nitrate such as alkali metal nitrate. Suitable nitrate salts in the present invention include sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, lithium nitrate, mixtures thereof and the like. Any compatible salt can be used including sodium, potassium, lithium, magnesium, calcium and the like. The most preferred nitrate salt is sodium nitrate. Other equivalent methods of nitrate supply can be used. For example, the pH of the total composition can be adjusted by the addition of nitric acid ions. The reaction of nitrate acid and basic salts contained in the composition will result in the release of carboxylic acid and the formation of nitrate salts. The nitrate salts serve to inhibit corrosion in the formulations of the present invention. The nitrate salt is preferably present in the formulation in an amount of about 0 to about 10.0 percent by weight, and more preferably in an amount of about 0.1 to about 0.1 to about 1.0 percent by weight. ?? TTTVOS? A AZOLES Azoles are present in the formulation to inhibit the corrosion of yellow metals such as copper and bronze.

Bronze thermostats and radiator caps are common as well as copper and bronze radiators. The azole compound that provides protection for copper and bronze from corrosion is selected from the salts of triazoles, pyrazoles, imidazoles, isooxazoids, isothiazoles, thiazoles, tiazoles, imidazoles, and the like. Generally, the alkali metal salts are used. Specific preferred azole compounds include 1, 2, 3-benzotriazole; 1, 2, 3-tolitriazole; 2-mercaptobenzothiazole sodium; and sodium 2-mercaptobenzimidazole. Suitable azo compounds in the present invention include mercaptobenzothiazole salts, tolithriazole salts, benzotriazole, mixtures thereof and the like. Typically, these azoles are preferably present in a concentration of fifty percent. However, a preferred azole compound consists of the mercaptobenzothiazole salts and tolithriazole salts. More particularly, a preferred azole compound is a mixture of sodium mercaptobenzothiazole and sodium tolitriazole which can be used in about a ratio of 3 to 1. The azoles are preferably present in the formulation in an amount of about 0.01 to about 10.0 percent. in weight, and more preferably in an amount of from about 0.05 to about 1.0 percent. Generally, the azole compound is used in amounts of approximately 0.4 parts by weight, based on 100 parts by weight of the aqueous liquid. MOT.TBDATE ADDITIVES Water-soluble molybdate which is preferred for use in the aqueous systems of the present invention can be any salt of molybdic acid which is readily soluble in water. These include both molybdates of alkali metals and alkaline earth metals as well as ammonium molybdate, the term "alkaline molybdate" which is used in a broad sense to include molybdates of alkali metals, alkaline earth metals and ammonium. Examples of useful molybdate are sodium molybdate, potassium molybdate, lithium molybdate and ammonium molybdates including ammonium dimolybdate and ammonium heptamolybdate. The compounds of alkali molybdate, sodium molybdate and potassium molybdate are preferred due to their availability and compatibility with the aqueous system as well as for economic reasons. The specific concentration of the molybdate ion will vary depending on the degree of hardness of the aqueous system, the temperature, and the amount of dissolved oxygen in the aqueous system. While molybdate ion concentrations above about 0.5 parts by weight per 100 parts by weight of the aqueous liquid can be employed in most cases molybdate ion concentrations above this limit usually does not provide significant improvements in the characteristics of the molybdate ion. inhibition or the aqueous system and are undesirable for economic reasons. The metals of transition metal compounds suitable for use in the present invention include, dehydrated disodium salts of molybdic acid, 2H20 sodium molybdate, molybdenum trioxide, silicoheteropolymoylbatates, phosphorusheteropolymoylbdates, mixtures thereof and the like. Any compatible transition metal can be used, including for example, molybdate, cobalt, cerium, mixtures thereof and the like. In addition, any acid salt can be used including sodium, potassium, lithium, calcium, magnesium and the like. The most preferred transition metal compound is the dehydrated disodium salt of molybdic acid or 2H20 sodium molybdate. The transition metal acids are used to inhibit corrosion in formulations of the present invention. The transition metal compound is preferably present in the formulation in an amount of about 0.001 to about 10.0 weight percent, and more preferably in an amount of about 0.01 to about 0.1 percent by weight. The molybdate ion is employed in amounts to provide a concentration in the aqueous system of at least about 0.001 parts by weight per 100 parts by weight of the aqueous liquid. Preferably about 0.005 to about 0.1 parts by weight per 100 parts by weight of the molybdate based on the aqueous liquid are employed. FOSFORO ADDITIVES Both water-soluble inorganic and organic phosphorus compounds are useful for inhibiting erosion-corrosion of aluminum cavitation in contact with aqueous liquids. The water soluble phosphates are generally used in amounts to provide a concentration of about 0.5 to about 2 parts by weight per 100 parts by weight of the aqueous liquid. These compounds include the preferred water-soluble alkali metal salts of orthophosphoric acid, pyrophosphoric acid-, and metaphosphoric acid. The orthophosphoric acid having series of three tribasic forms of salts, potassium hydrogen phosphate, disodium hydrogen phosphate, and trisodium phosphate. Useful organic phosphates include the oxysters of phosphoric acid, as well as amides and triesters thereof. The most common acid phosphorus esters which are useful are the mono-, di-, and triesters of orthophosphoric acid. These may be alkyl phosphates, aryl phosphates and alkyl aryl phosphates. Representative alkyl groups having 1 to about 18 carbon atoms which may be present in the alkyl phosphates include methyl, ethyl, propyl, isopropyl, and n-butyl, isobutyl, etc. Representative substituted alkyl groups which may be present in the phosphorus esters include alkyl groups substituted with halogens, especially chlorine, fluorine, and with alkoxy groups. Examples of substituted alkyl groups include butoxyethyl, 2-chloroethyl, 2-nuoroethyl, etc. Examples or other groups which may be present in the phosphorus esters include alkyl groups substituted with halogens, especially chlorine and fluorine, and with alkoxy groups. Examples of substituted alkyl groups include butyloxyethyl, 2-chloroethyl, 2-fluoroethyl, etc. Examples of aryl groups which may be present in the phosphorus esters include phenyl, xylyl, cresyl and halogenated phenyl. Phosphates suitable in the present invention include dipotassium phosphate, disodium phosphate, monopotassium phosphate, tripotassium phosphate, monosodium phosphate, trisodium phosphate, mixtures thereof and the like. Any compatible salt can be used including sodium, potassium, lithium, and the like. The most preferred phosphate is a dipotassium phosphate. The phosphates are preferably in a fifty percent solution. The phosphates serve to buffer and inhibit corrosion in the formulations of the present invention. The phosphate is preferably in the formulation as fifty percent dipotassium phosphate in an amount of about 0.1 to about 10.0 weight percent, and more preferably in an amount of about 1.0 to about 4.0 weight percent. SILOXANO-ST TCATO COPOLYMERS Sulfonated and phosphonated siloxane-silicate copolymers can be formed in situ from the combination of a water-soluble silicate and a water-soluble siloxane. In the preferred composition, the silicone-silicate copolymer is selected from the group comprising silylalkyl phosphonates, alkaline siliconates and salts thereof, and sulfosiloxane-silicates and salts thereof and / or mixtures thereof. It is believed that these copolymers provide improved corrosion inhibition of metals upon the use of water soluble silicates. The stabilized silicate, ("siloxane copolymers"), substantially inhibits the gelation tendency of the water-soluble silicate at a pH of about 7 to about 11. The anti-corrosive activity of the soluble silicate is maintained in the copolymer compared to the non-soluble silicate. Ordinarily stabilized such as sodium silicate. The stabilized silicone / silicate technology is disclosed in U.S. Patent Nos. 4,370,255; and No. 4,362,644; and No. 4,354,002, all incorporated herein by reference. Other siloxane-silicate copolymers can be used in combination with water-soluble molybdates and water-soluble salts and phosphorus acid esters. These are described in U.S. Patent No. 3,341,469; Do not . 3,337,496; No. 3,312,622; Do not . 3,198,820; No. 3,203,969; No. 3,248,329; and not . 4,093,641 all incorporated herein for reference. The siloxanes / silicates are used to inhibit corrosion in the formulation of the present invention. The silicone silicates are preferably present in the formulation in an amount of about 0.1 to about 10.0 weight percent, and more preferably in an amount of about 0.2 to about 1.0 weight percent. DEPENDENT Any suitable defoamer, well known in the art, is suitable for the formulations herein. Suitable defoamers include, for example, nonionic surfactant PLURONIC® L-61 (commercially available from BASF® Corporation) or liquid defoamer PATCOTE® 415 (commercially available from Pateo Specialty Chemicals Division, American Ingredients Company). The defoamer may be present in an amount up to about 10.0 percent by weight and more preferably present in an amount of about 0.001 to about 10.0 percent by weight, and most preferably, in an amount of about 0.01 to about 0.05 percent by weight.

ADDITIVES Other additives such as isolation agents, dyes, or biocides can be added to the antifreeze / coolant solution. Synergistic effect The previous synergistic combination of selected polycarboxylates and stabilized silicates ("siloxane"), in combination with inhibitors, is particularly suitable for corrosion protection of aluminum in contact with an aqueous system to provide corrosion protection, cavitation erosion or aluminum water pumps in a long-lived anti-freeze composition that provides additional protection compared to other compositions based on stabilized silicates and silicates without the addition of polycarboxylates. Other corrosion inhibitors are optionally added to the aqueous liquid which exhibits synergy together and in combination with the siloxane / polycarboxylate components. The synergistic combination of corrosion inhibitors useful for corrosion inhibiting cavitation erosion of aluminum water pumps is generally effective in aqueous alkaline corrosive media. For example, the corrosion inhibitors of the invention are useful in aqueous alcohol-based antifreeze compositions which are generally maintained at a pH of at least 6, and preferably about 7 to about 11. The corrosion inhibitors of the invention They are also useful in the best transfer media used in cooling towers. The antifreeze concentrates of the invention are first prepared by dissolving in a water-alcohol mixture (preferably ethylene glycol in combination with diethylene glycol) a water-soluble silicate, an organosiloxane, preferably a phosphonated siloxane, or sulfonated siloxane, and a molybdate, tungstate or alkali metal selenate. Subsequently the composition is brought to basic by the addition of sodium or potassium hydroxide. Where corrosion protection of copper and copper-containing alloys in addition to aluminum in contact with the aqueous antifreeze concentrates of the invention is also required, an alkali metal azole such as sodium mercaptobenzothiazole or sodium tolyltriazole is generally added as a 50 percent aqueous solution. Optionally, an antifoam agent is used which may be a low froth polyoxyethylene adduct of a hydrophobic polyoxypropylene base having a molecular weight of about 1750 where the oxyethylene content is about 10 weight percent of the molecule. Low foaming nonionic surfactants can be used which are described in U.S. Patent No. 3,340,309; No. 3,504,041; 3,770,701; and 2,425,755. Descriptions of the low foaming nonionic surfactants in the aforementioned patents are incorporated herein by reference. The composition of the resulting antifreeze concentrate can be diluted with water according to a prior practice to produce an antifreeze fluid or heat transfer medium having a desired freezing point. As a general rule, the antifreeze concentrate used to prepare the refrigerant can be diluted with about 1 to about 3 volumes of water to achieve a fluid refrigerant which is circulated in the engine cooling system or in a cooling tower. Smaller or larger amounts of water can be added as necessary to prevent coolant freezing. In order to obtain the desired corrosion resistance for cavitation erosion of aluminum water pumps in contact with aqueous liquids containing a metal corrosion inhibitor of the siloxane-silicate copolymer, it is necessary to provide the required amounts of the phosphate and at least one of a molybdate, tungstate, or selenate in the amounts specified above. EXPERIMENTAL EVALUATION The following examples serve to further illustrate the present invention and should not be construed in any way as limiting the scope thereof. The ASTM D-1384 -87 test is used to evaluate the corrosion inhibitor formulations of the present invention, ASTM D-1384 -87 is the standard test method for corrosion testing of engine coolants in glassware and simulates some conditions of global operation of cooling systems. The ASTM D-2570 test is used to evaluate the corrosion inhibitor formulations of the present invention, ASTM D-2570 is the standard test method for simulated service testing of engine coolants in glassware and simulates better the conditions of global operation actual cooling systems that test D-1284-87. The formulations used in the following Examples (1-4) are present in Table 1.

TABLE 1 (Formulations) Composition A (without polycarboxylate) Composition B (with polycarboxylate GOOD-RITE® K752) Composition C (with SOKALAN® polycarboxylate CP-l2s) The temperature, test duration, and cleaning procedures of metal specimens are all conducted according to ASTM D-1384-87 specifications. All changes in weight are in milligrams per specimen (mg / specimen). A negative weight loss is a weight gain. The step specification refers to weight loss. TABLE 2 (Mg Weight Loss / Specimen of ASTM D-1384) The results in Table 2 show that the Formulations A, B, and C pass the ASTM D-1384 weight loss tests.

TABLE 3 The results in Table 3 show that Formulations A, B, and C pass the simulated service weight loss tests of ASTM D-2570. On the other hand, an ASTM D-4340 test is carried out which shows no difference in the corrosion ratio of the compositions A, B, and C in mg / cm-cm / week as follows: TABLE 4 On the other hand, an ASTM D-2809 test is carried out which shows very little difference in the pump cavitation rate of compositions A, B, and C in mg / cm-cm / week as follows: TABLE 5 The three compositions of refrigerants A (without polycarboxylate), B (with polycarboxylate GOOD-RITE® K752), and C (with polycarboxylate SOKALAJSr1 CP-12s) are subjected to the Ford motor dynamometer test, FLTM BL 2-2. The test involves a four-cylinder OHC engine operating at 2400 RPM, torque effect 28 83 Nm (bhp). The coolant temperature is 107 +/- ° C, and the drop between the radiator is 20 +/- ° c. The duration of the test is sixteen (16) hours of operation and eight (8) hours without operation per day for forty-two (42) days of operation (672 hours). At intervals of ninety-six (96) hours the refrigerants are sampled and analyzed chemically and physically. EXAMPLES The following examples further serve to illustrate the present invention and should not be construed as limiting the scope thereof in any way. Example 1 As shown in Figure 1, the polymeric polycarboxylate containing compositions of coolant B (with polycarboxylate GOOD-RITE * K752), and C (with polycarboxylate SOKALAN0 CP-22s) completes the FLTM BL 2-2 test of the Ford engine dynamometer with satisfactory aluminum corrosion results. The composition of coolant A (without the polycarboxylate) does not pass the test. After 200 hours the aluminum corrosion begins with the specimen in Composition A. Corrosion of aluminum results in 160 ppm of aluminum in solution after 600 hours. No aluminum or corrosion products are observed in solution for Compositions (B and C). Example 2 Figure 2 shows the percentage of silicate in solution for Composition A (without polycarboxylate) against composition B (with polycarboxylate GOOD-RITE0 K752) as a function of the addition of the polycarboxylate, specifically GOOD-RITEF K752 in combination with stabilized siloxane silicate and other components that act synergistically including water-soluble nitrate, water-soluble phosphates, azole compound, water-soluble molybdate, sodium hydroxide in the glycol solution. As shown in the FLTM BL 2-2 test of Ford engine dynamometer, the silicate level falls precipitously for Composition A without the selected polycarboxylate additive. At 100 hours the silicate level of Composition A is less than 40% of the initial value. It should be noted that the silicate level of Composition A increases near the end of the test. The theory of the invention is that the increase is due to the corrosion of the silicon containing aluminum motor alloy. Composition B containing GOOD-RITE1 K752 polycarboxylate and stabilized silicate "siloxane" compound shows a relatively constant silicate depletion ratio, even a sufficient amount of the silicate remains in solution for the duration of the test. These results show that at highway speeds, Composition A of the refrigerant must be changed after 13,000 miles, while Composition B of the refrigerant protects the engine above 40,000 miles. This is based on the estimated speed of 65-75 miles per hour. Example 3 Figure 3 shows the effect of adding Composition C (with SOKALAN polycarboxylate <; "CP-12s) to the antifreeze solution used in combination with the stabilized siloxane silicate and other synergistically active components including water-soluble nitrate, water-soluble phosphates, water-soluble azole molybdate compound, sodium hydroxide in the glycol solution In a similar way as shown in Figure 1 in the FLTM BL 2-2 test of Ford engine dynamometer, when Composition B is used (with GOOD-RITE * K752 polycarboxylate) Composition C (with SOKALAN polycarboxylate "CP -12S) retards silicate depletion for the duration of the standard 672 test. On the other hand, when this test is extended to 1064 hours, more than 50% of the silicate remains in solution without exhibiting any aluminum corrosion products in solution, which is equivalent to approximately 70,000 race miles. Example 4 Figure 4 compares all three compositions, the Composition A (without polycarboxylates), Composition B (with GOOD-RITE polycarboxylates K752), and Composition C (with polycarboxylates SOKALAN0 CP-12s), wherein Compositions B and C improve the stability of the siloxane silicate of the coolants especially in combination with the other components that act synergistically. Figure 4 shows that while both Composition C (with polycarboxylates SOKALAN0 CP-12s) and Composition B (with polycarboxylates GOOD-RITEF K752) improve silicate stability, the solution of Composition B (with polycarboxylate GOOD-RITE K752) is more efficient since it is 2.5 times lower in concentration than the solution of Composition C (with polycarboxylates SOKALANF CP-12s), even the silicate depletion ratio is lower. The extrapolation to silicate content of 50% suggests a useful life in more than 100,000 miles of road speed by using Composition B (with polycarboxylate GOOD-RITE0 K752) in combination with the stabilized silicate siloxane that suggests synergism which until now it had been produced with other stabilized silicate compositions alone or in combination with other components that act synergistically therewith to produce a long-lived antifreeze composition. The full description of each of the US Patents cited elsewhere hereinbefore is incorporated herein for reference as being fully indicated in this specification. The detailed description mentioned herein is given primarily for clarity of understanding and is not necessarily understood as limitations thereof, the modification will become obvious to those skilled in the art of reading this description and may be made without departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not proposed to be limited by the specific exemplifications presented hereinabove. On the other hand, what is proposed to be covered is within the spirit and scope of the appended claims.

Claims (39)

1. CLAIMS 1. An antifreeze / coolant solution to inhibit the corrosion of metals and inhibit the oxidation of minerals based on 100 parts by weight of the glycol-based solution, characterized in that it comprises: A polymeric polycarboxylate which is at least one selected of the group consisting essentially of (i) a polyacrylic acid modified with secondary alcohol, a sodium salt of a copolymer of acrylic acid and maleic acid, mixtures of sodium polyacrylate and polyacrylic acid in water, and combinations thereof. A salt which is at least one selected from the group consisting essentially of sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, lithium nitrate, and combinations thereof in an amount of about 0 to about 10.0 percent in weigh. An azole compound which is selected from the group consisting essentially of sodium mercaptobenzothiazole, sodium tolitriazole, water soluble triazoles, pyrazoles, imidazoles, isooxazoles, isothiazoles, thiazoles, thiadiazole, 1, 2, 3-benzotriazole, 1, 2, 3-tolythriazole, sodium 2-mercaptobenzothiazole, and sodium 2-mercaptobenzimidazole in an amount of about 0.01 to about 10.0 weight percent; A silicone-silicate copolymer in an amount of about 0.1 to about 10.0 weight percent; A phosphate compound which is selected from the group consisting essentially of dipotassium phosphate, disodium phosphate, monopotassium phosphate, tripotassium phosphate, monosodium phosphate, trisodium phosphate, and mixtures thereof; A transition metal compound selected from the group consisting essentially of dehydrated disodium salt of molybdic acid, molybdenum trioxide, silicohetero-polyimolydates and / or phosphorohetero-polyamybdates, sodium molybdate, potassium molybdate, lithium molybdate, ammonium molybdate, ammonium dimolybdate, and ammonium heptamolybdate in an amount of about 0.001 to about 10.0 weight percent; and A glycol compound selected from the group consisting essentially of ethylene glycol, diethylene glycol, propylene glycol, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and combinations thereof which achieve equilibrium of the solution.
2. 2. The antifreeze / coolant solution according to claim 1, characterized in that the polymeric polycarboxylate has a molecular weight in a range of between about 500 to 12,000.
3. 3. The antifreeze / coolant solution according to claim 1, characterized in that the polymeric polycarboxylate has a molecular weight in a range of between about 500 to 4,000.
4. 4. The antifreeze / coolant solution according to claim 1, characterized in that the polymeric polycarboxylate has a molecular weight in the range of between about 500 to 1,800.
5. 5. The antifreeze / coolant solution according to claim 1, characterized in that the azole compound is a mixture of sodium mercaptobenzothiazole and sodium tolitriazole.
6. The anti-freeze / coolant solution according to claim 5, characterized in that the sodium mercaptobenzothiazole and sodium tolitriazole are present in approximately a 3 to 1 ratio.
7. 7. The antifreeze / coolant solution according to claim 1, characterized in that the azole compound is present at approximately a 50% concentration.
8. 8. The antifreeze / coolant solution according to claim 1, characterized in that the nitrate salt is sodium nitrate.
9. 9. The antifreeze / coolant solution according to claim 8, characterized in that the nitrate salt is present in an amount between about 1% by weight to about 3% by weight.
10. 10. The antifreeze / coolant solution according to claim 1, characterized in that the phosphate salt is dipotassium phosphate.
11. 11. The antifreeze / coolant solution according to claim 1, characterized in that the phosphate salt is present in approximately a 50% solution.
12. 12. The antifreeze / coolant solution according to claim 1, characterized in that the transition metal compound is the dehydrated disodium salt of molybdic acid.
13. 13. The antifreeze / coolant solution according to claim 1, characterized in that it includes a defoamer.
14. The anti-freeze / coolant solution according to claim 13, characterized in that the defoamer is present in an amount between about 0.001 to about 10.0% by weight.
15. 15. The antifreeze / coolant solution according to claim 1, characterized in that it includes an isolation agent.
16. 16. The antifreeze / coolant solution according to claim 1, characterized in that it includes a dye.
17. 17. The antifreeze / coolant solution according to claim 1, characterized in that it includes a dye including a biocide.
18. 18. The antifreeze / coolant solution according to claim 1, characterized in that silicone-silicate copolymer is present in an amount between about 0.1 about 6.0% by weight.
19. 19. The antifreeze / coolant solution according to claim 1, characterized in that the silicone-silicate copolymer is selected from the group consisting of silicone alkylphosphonates of siliconates and salts thereof, sulfonate-silicates of arylalkylsilicones and salts thereof, and sulfosiloxane-silicates and salts thereof.
20. 20. The antifreeze / coolant solution according to claim 1, characterized in that the polymeric polycarboxylate is selected from the group consisting of GOOD-RITE0 K732, GOOD-RITE0 K752, SOKALAN0 CP-12S, SOKALAN0 CP-10, and SOKALAN0 CP -10S.
21. 21. A solution of antifreeze / coolant for glycol-based automotive to inhibit the corrosion of metals and inhibit the mineral oxide based on 100 parts by weight of the glycol-based solution, characterized in that it comprises a polymeric polycarboxylate which is less one selected from the group consisting essentially of (i) a polyacrylic acid modified with secondary alcohol having a molecular weight of less than 10,000, a sodium salt of a copolymer of acrylic acid and maleic acid having a molecular weight of less than of 10,000, mixtures of sodium polyacrylate and polyacrylic acid in water having a molecular weight of less than 10,000, and combinations thereof. A salt which is at least one selected from the group consisting essentially of sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, lithium nitrate, and combinations thereof in an amount of about 0 to about 10.0 percent in weigh. An azole compound which is selected from the group consisting essentially of sodium mercaptobenzothiazole, sodium tolitriazole, water soluble triazoles, pyrazoles, imidazoles, isooxazoles, isothiazoles, thiazoles, thiadiazole, 1, 2, 3-benzotriazole, 1, 2, 3-tolythriazole, sodium 2-mercaptobenzothiazole, and sodium 2-mercaptobenzimidazole in an amount of about 0.01 to about 10.0 weight percent; A silicone-silicate copolymer in an amount of about 0.1 to about 10.0 weight percent; A phosphate compound which is selected from the group consisting essentially of dipotassium phosphate, disodium phosphate, monopotassium phosphate, tripotassium phosphate, monosodium phosphate, trisodium phosphate, and mixtures thereof; A transition metal compound selected from the group consisting essentially of dehydrated disodium salt of molybdic acid, molybdenum trioxide, silicohetero-polyimolydates and / or phosphorohetero-polyamybdates, sodium molybdate, potassium molybdate, lithium molybdate, ammonium molybdate, ammonium dimolybdate, and ammonium heptamolybdate in an amount of about 0.001 to about 10.0 weight percent; and A water-soluble alcohol selected from the group consisting essentially of ethylene glycol, diethylene glycol, propylene glycol, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and combinations thereof which achieve equilibrium of the solution.
22. 22. The antifreeze / coolant solution according to claim 21, characterized in that the polymeric polycarboxylate has a molecular weight in a range of between about 500 to 4,000.
23. 23. The antifreeze / coolant solution according to claim 21, characterized in that the polymeric polycarboxylate has a molecular weight in the range of about 500 to 1,800.
24. 24. The antifreeze / coolant solution according to claim 21, characterized in that the azole compound is a mixture of sodium mercaptobenzothiazole and sodium tolitriazole.
25. 25. The antifreeze / coolant solution according to claim 24, characterized in that the sodium mercaptobenzothiazole and sodium tolitriazole are present in approximately a 3 to 1 ratio.
26. 26. The antifreeze / coolant solution according to claim 21, characterized in that the azole compound is present in approximately a concentration of 50%. .
27. 27. The antifreeze / coolant solution according to claim 21, characterized in that the nitrate salt is sodium nitrate.
28. 28. The antifreeze / coolant solution according to claim 27, characterized in that the nitrate salt is present in an amount between about 1% by weight to about 3% by weight.
29. 29. The antifreeze / coolant solution according to claim 21, characterized in that the phosphate salt is dipotassium phosphate.
30. 30. The antifreeze / coolant solution according to claim 21, characterized in that the phosphate salt is present in approximately a 50% solution.
31. 31. The antifreeze / coolant solution according to claim 21, characterized in that the transition metal compound is the dehydrated disodium salt of molybdic acid.
32. 32. The antifreeze / coolant solution according to claim 21, characterized in that it includes a defoamer.
33. 33. The antifreeze / coolant solution according to claim 32, characterized in that the defoamer is present in an amount between about 0.001 to about 10.0% by weight.
34. 34. The antifreeze / coolant solution according to claim 21, characterized in that it includes an isolation agent.
35. 35. The antifreeze / coolant solution according to claim 21, characterized in that it includes a dye.
36. 36. The antifreeze / coolant solution according to claim 21, characterized in that it includes a dye including a biocide.
37. 37. The antifreeze / coolant solution according to claim 21, characterized in that silicone-silicate copolymer is present in an amount between about 0.1 to about 6.0% by weight.
38. 38. The antifreeze / coolant solution according to claim 21, characterized in that the silicone-silicate copolymer is selected from the group consisting of silicone alkylphosphonates of siliconates and salts thereof, sulfonate-silicates of arylalkylsilicones and salts thereof, and sulfosiloxane-silicates and salts thereof.
39. 39. The antifreeze / coolant solution according to claim 21, characterized in that the polymeric polycarboxylate is selected from the group consisting of GOOD-RITE0 K732, GOOD-RITE * K752, SOKALAN0 CP-12S, SOKALAN8 CP-10, and SOKALAN0 CP-10S.