CA2027302A1 - Silicate-free coolant composition having corrosion inhibitor therein - Google Patents

Abstract

SILICATE-FREE COOLANT COMPOSITION
HAVING CORROSION INHIBITOR THEREIN

Abstract of the Disclosure In addition to a freezing point depressant, aqueous silicate-free coolant compositions, especially anti-freeze formulations, contain corrosion inhibitors which are phosphate esters of alkyl polyoxyethylene polymers and/or phosphate esters of polyoxyethylene/polyoxypropylene copolymers.

Description

Express Mail No. MB17988469~
October 11, 1989 2561B

~ILICA~E-FREE CODL~NT CO~POSITIO~
~AYING CORROSION IN~IBITOR ~EREIN

8ACKGROUND O~ T~E IffVEN~ION

1. Field of the Invention The pre~ent invention pertain~ to the field of coolant compositions. More apecifically, the present invention pertains to coolant compositions which contain corrosion inhibitors. Corro~ion inhibitors are u~ed in liquids which contact metals, the corrosion inhibitors reducing the rate of corrosion of the metal by the liquid.
Commonplace examples of such liquids are engine coolants (such as anti-freeæe formulations) as well as hydraulic fluids. More specifically, the pre ent invention relates to the uje of phosphate esters of organic alkyl polyoxyQthylene polymers and phosphate esters of polyoxyethylene/polyoxy-propylene copolymers for imparting corrosion inhibition to liquid compositions. Furthermore, the liqui~ compositions of the present invention are aqueous composition~.

.. . . ... ~ .... .. . . ., ., .. ~ .... .. . . . . . .. . . .

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2. Description of the Prior Art Several members of the groups of inhibitors described herein have been ~ade and sold by BASF Corporation for more than one year. However, each of these ~pecies was designed and sold for i~s surfactant characteristic~, and Applicants have no knowledge that any of these surfactants ever have been utilized in coolant compositions.
The closest prior art of which ~pplicants are aware i~ U.S. 3,931,029. This p~tent, which pertains to corrosion inhibited anti-freeze compositions, discloses the use of particular anti-foam agents, which anti-foam agents m~ include silicone anti-foam agents, aliphatic alcohols of 10 carbon atoms or more, organic pho~phates and phthal~te~, and convent~onal nonionic synthetic detergents. The '029 patent refers generally to silicDne antifoam agents, as well as antifoam a~ents comprising alcohol~ of 10 carbon atoms or more, organic phosphates and phthalates, and conventional nonionic surfactants. Mor~ particularly the '029 patent refers to alkoxylated nonionic synthetic detergents includ-ing polyoxyalkylene adducts of hydrophobic bases. 5pecifi-cally, mentioned are polyoxyethylen~ esters of higher fatty acids, ethylene oxide adducts of higher aliphatic alcoh~ls~
conjugated polyoxya}kylene compounds, polyoxypropylene-... , .. . , . . . . . . . _ . . .. . . . . . .

~tij,i, polyoxyethylene block copolymers, and ethoxylated andpropoxylated adducts of ethylene diamine. The '029 patent nowhere specifically mentions phosphates of these particular organic compounds.
Although the '029 patent utilizes anti-f~amin~
agents related to the corrosion inhibition agents utilized in the present invention, the '029 patent repeatedly states that the ethylene oxide content of the anti-foam agent should not exceed 20 percent by weight of the molecule. In stark contrast, Applicants of the present invention have found that when the ethylene oxide residue conQtitutes less than 20 percent by weight of the total molecular weight of the molecule, the molecule is rendered substantially insoluble in the agueous coolant formulation. Rather, the present invention requir~s a minimum of at least 20 percent by weight of the total molecule of ethylene oxide residue, this higher percentage rendering the molecule soluble so that the corrosion inhibition ch~racteri~tics are pro-duced. Furthermore, ~he present invention is directed at phosphate esters of these polymers, and the '20~ patent nowhere even mentions the inhibitors u~ed in the composition of the present invention.

~t3 U.S. 4,686,058, entitled l'Thickened Water Based Hydraulic Fluids", states that certain compounds act as thickening agents when used in hydraulic fluids. The '058 patent states that the primary purpose of increasing the viscosity of the hydraulic fluids is to reduce leakage of the fluid in the mechanical equipment utilized. The '058 patent refers to thickeners of the polyglycol type. More specifically, the '058 patent refers to polyoxyalkylene polyols having a molecular weight of about ~,000 to 40,000, prepared by reacting an alkylene oxide with linear or branched chain polyhydric alcohol. Furthermore, the '058 patent states that the hydr~ulic fluid having the polyether polyol thickeners will lose viscosity unless there i~ ~lso present a viscosity loss reducing compound. ~he viscos~ty loss reduc~ng compounds suggested in the '058 patent include et~ylene glycol, propylene glycol, propylene glycol polymers and ~opolymers containing at least 50 percent by weight oxypropylene groups, a dimercaptothiadiazole, neodecanoic acid, hindered phenol ~ntioxidants, and ~ixtures thereof.
The ~058 pa~ent also refer~ to propylene glycol polymers or ~opolymers having molecular weight~ of from 75 to 5000, the copolymers being heteric or block c~polymers. ~he '05~
patent also re~ers tG phosphate esters of polyoxyethylated alcohols, wherein the residual alcohol moieties consist of linear or branched chain alkyl groups oP from 6 to 30 carbon atoms.
The composition of the present invention ~iffers from the '053 patent in that the composition of the present invention pertains to coolant~, rather than hydraulic fluids. Purthermore, the composition of the present invention does not compri~e such thickeners as polyoxy-~lkylene polyols having a molecular weight of about 2000 to 40,000. Since it is apparent that the '058 patent utilizes viscosity loss reducing compounds for the purpose of preeerYing the thickening characteri~tic of the polyoxy-alkylene polyols, if such polyoxyalkylene polyols are not present, as in the case of the present invention, there is no need for the viscosity loss reducing agents sug~ested by the '058 patent. The present invention pertains to coolants, rather than to hydraulic fluids. There i~ no need to increase the viscosity of a coolant. Rather, it would be hi~hly undesirable to do so.
BRIEF SUMMARY OF T~E INVENTIO
The present invention pertains to a silicate-free coolant composition which comprises at least one corr4sion inhibitor. The coolant composition comprises at least one member select~d from the group consi~tin~ of:

A. phosphate esters of ethylene diamine ini~iated polyoxy-ethylene/polyoxypropylene copolymers. ~hese copolymers may be block copolymers or heteric copolymer6. The~e copolymers have the following general formula:

po4(EO)y ~(PO)X / ~P~ (EO)y _pO4 2 NC2H4N ~
PQ4-~EO)y ~~PO)x / (PO)X -~EO)y _pO4 2 Ir, ~his formula, "EO" represents an ethyle~e oxide residue, while "PO" represents an propylene oxide residue. Y is selected so that the total weight percent of ~O in the copolymer is from greater than 20 to about 40, based on the molecular weight of the copolymer. The molecular w~ight of the PO in the copolymer is from ~bout 1500 to about 7000.
This copolymer is present in the coolant compo-5ition at a concentration of from about 0.05 weight percent to ~bout 2 weight percent, based on the weight of the neat composition.

. . .

~,~ t,~ '~J ~ ;.J ~ ,J

(B) phosphate esters ofpolyoxypropylene/polyoxyethylene copolymers, which copolymers may be block copolymers or heteric copolymers. The copolymers are of the following general formula:

2po4 (EO)y -(PO~ - (EO)y - po~

wherein "EO" represents an ethylene oxide residue, and wherein "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent ~f EO
in the copolymer is from greater than 20 to about 80, based on the molecular weight of ~he copolymer. The ~olecular weight of the PO in the copolymer is from about 950 to about 4000. The copolymer i5 present in the coolant composition at a concentration of from about 0.05 weight percent to about 2 weight percent, based on th~ weight of the neat composition.

.. , -f) ~ `J ~ 'iJ.' (C) phosphate esters of a polyoxyethylene/polyoxypropylene copolymers, which copolymers may be block copolymers or heteric copolymers, these copolymers being of the following general ~ormula:

-2po ~ ~PO)X ~ (EO)y ~ (PO)X 4 whereir. "EO" represents an ethylene oxide residue and wherein "PO" represents a propylene oxide residue, and wherein X is selected so that the total molecular weight of the PO in the copolymer is from about 1000 to about 3100, based on the molecular weight of the copolymer, an~ wherein the weight percent of the EO in the copolymer i~ from greater than 20 to about 80 percent by weight, based on the molecular weight of the copolymer. ~he copolymer i~ present in the composition at a concentration from about 0~05 percent ~y weight to about ~ percent by weight, based on the wei~ht of the neat composition.

,. ~ . .. .. . . . . .. . . .. . . . .... . . ..

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(D) phosphate esters of alkyloxyethylate polymers of the general formula:

R - O - ~EO)y _ po4 2 wherein R represents a linear or branched alkyl moiety having from 6 to 18 carbon atoms, and wherein "EO" repre-sents a residual ethylene oxide moiety, and wherein the alkyloxyethylate polymer has an average molecular weight of from about 200 to about 3000 and an 2thylene oxide residue content of from greater than 20 to about 80 weight pPrcent, based on the molecular weight of the polymer. The concen-tration of the alkyloxyethylate polymer in the coolant composition is from about 0.05 percent by weight to about 2 percent by weight, based on the weight of the neat compo-sition.

(E) phosphate esters of alkylphenol oxyethylate polymer~ of the following ~eneral formula:

~,' "JJ 3~, ~ - O - IEO)y - H

wherein R is a branched or linear alkyl moiety having from 4 tO 12 carbon atoms, and wherein EO represents a residual ethylene oxide moiety, and wherein the polymer has an ethylene oxide residue content of from about 40 to about 90 weight percent, based on the molecular weight of the polymer. The conc~ntration of the alkylphenol oxyethylate polymer in the coolant composition should be from about 0.05 weight percent to about 2 weight percent, based nn the weight of the neat composition.

.
(F) phosphate esters of fatty alcohol heteric ethylene-oxide/propyleneoxide copolymer of the following general formula:

R - O - ~ ~PO) , (EO) l_ po~ 2 L F l-FJ

wherein R represents a branched or linear alkyl moiety having from 6 to 18 carbon atoms, and wherein E0 represents a residual ethylene oxide moiety, and wherein P0 represents a re~idual propylene oxide moiety. F and n are ~elected so th~t the copolymer has a resulting weight percent E0 of from greater than 20 to about 95, based on the molecular weight of the copolymer. In the heteric block, F has a value of fronl about 0.1 to about 0.99. The concentration of the copolynler present in the composition is from about 0.05 weight percent to about 2 weight percent, based on the weight of the neat composition.
The specific member or members of the above group Gf inhibitors, as well as the concentration of the inhibitor (Gr inhibitors), is selected so that the resulting liquid composition exhibits a passivation current o~ less than a standard reference composition, as is described below.
Applicants have surprisingly found that the above group of polymers produces advantageous corrosion inhibition of for aluminum exposed to coolant compositions. 80th Table I and Table II, below, indicate the advantageous effect~ of usi.ng these polymers in coolant compositions. Furthçrmore, Applicant~ have discovered that the above group of poly~er~, when utilized in liquid co~positions used ~s coolants, produce highly advantageous results with respect to the corrosion inhibition of aluminum.
Prior art anti-freeze compositions ~ave tradition-ally utilized silieates to provide a hi~h degree of ~orro-sion inhibition, so that metal parts in contact with the coolant are not subjected to a high ~egree of corrosion due to contact with the coolant. ~owever, it is believed that the presence of silicate in coolant Eormulations may result in deposits of silica gel particulates which have a detri-mental effect upon pump seals, etc. The organic polymeric phosphate ester inhibitors of the present invention enable the complete elimination of the silicates from the compo-sition, so that the deposition of ~ilica g21 i5 eliminated. It has unexpectedly been found that coolants employing the inhibitors of ~he present invention ~ay achieve a correspondingly high degree of corrosion inhib-ition of aluminum, without silicates.

DETAILED DESCRIPTION OF THE PR~FERRED E~BODI~ENTS
The coolant composition of the pre~nt ~nvention employs one or more of a ~pecific group of pho~phate ~ster6 og polyoxyethylene/polyoxypropyl~ne copolymers ~nd phospha~e '; ' ~ 1 ' " i, esters of alkyl polyoxyethylene polymers, for the purpose ~f reduci~g the ~otential f~r the coolant composition tv corrode metals. It has been found that each of these groups effectively produce corrosion inhibition when the agent is present within a certain concentration range. Furthermore, it has been unexpectedly found that these corrosion inhib-ition agents effectively reduce the corrosive character of the coolant when these agents are used in the absenoe of silicates.
Certain phosphate esters of ethylene diamine initiated polyoxyethylene/polyoxypropylene copolymer~ may be used as corr~sion inhibitors. These copolymer6 ~ay be block copolymers or heteric copolymer~. These polymer~ are well known to those ~f skill in the art, and can be produced in acoordance with methods described in 2,979,528, which is here~y incorporated by r~ference. U.S 3,986,922 describes how to produce the phosphate esters of the~e poly~er~, and is accordingly also incorporated by reference. Generally, the non-phosphated polymers are char~cterized in that they comprise an ethylene oxide residue (-C~-C~-O-) of from greater than 20 weight percent to about ~D weight percent, based on the ~olecular weight of the polymer ~ole~ule.
~owever, it i~ preferable that the molecule compri~es rom . . . .. . ,, . ... ....... ... .. .... . , .. . . _ ... ..... . . . . ~ . . . . . . .. . . . .

about 30 to about 40 weight percent ethylene oxide residue, and it is most preferred that the polymer molecule comprise ~bout 3Q weight percent ethylene oxide residue~ In general, the average molecular weight of the polyoxypropylene in the copolymer molecule averages from about 1500 to about 7500, Hnwever, it is preferred that the polyoxypropylene in the ~op~lymer have a molecular weight on the average of from about 4~00 to about 7000, and it is most preferred that the average molecular weight of the polyoxypropylene in the copolymer is about 6000. In general, the coolant compo-sition should comprise copolymer in an amount from about 0.05 weight percent to about 2 weight percent, based on the weight of the neat composition.
The coolant composition of the present invention ~i may comprise phosphate ester~ of polyoxypropylene~polyoxy-ethylene copolymers, which copolymer~ may be block copoly-mer~ or heteric copolymers. These polymers are also well known to those of skill in the art, and can be produced in accordance with methods described in U.SO 2,674,619, which i6 hereby incorporated by referenceO Again, U.S. 3,9R6,Q22 teaches methods for phosphorylation oP these polymer , and i~ accordingly incorporated by reference. In general, these copolymers have an ethylene oxide residue content of from .. . . , . . .. .. ........ . _._ .. . . .. . . . . . ... . ... . .

greater than 20 weight percent to about Bn weight percent, based on the molecular weight of the cop~lymer mol~cule.
~owever, i~ is preferred that the ethylene oxide residue content is from greater than 20 weight percent to about 40 weight percent, and it is most preferred that the ethylene oxide residùe content is about 30 weight percent~ based on the molecular weight of the copolymer molecule. In general, the molecular weight of the polypropylene oxide residue in the copolymer is from about 950 to about 4000. More preferably, ~he molecular weight of the propylene oxide residue is from about 1100 to about 2000, and mo~t prefer-ably the molecular weight of the propylene oxide residue is around 1620. In general, the concentration of the polyoxy-propylene/polyoxyethylene copolymer in the coolant compo-sition is from about 0.0~ weight per~nt to about 2 weight percent, based on the weight of the neat coolant compo-~ition. Most preferably, the concentration of ~he copolymer corrosion inhibitor in the coolant compo~tion is around 0.2 percent by weight, based on the weight of the neat coolant composition.
The coolant composition of the present invention may comprise phosphate ester polyoxyetbylene/polyoxy-propylene copolymer G4rrOSiOn inhibitor5 which may b~ block .. , . ,,, .. . . ~ . ,, .. ~ , . . . .. .. . ..

copolymers, or heteric copolymers. In general, these copolymers have an e~hylene oxide residue content of from ~reater than 20 welght p~rcent to about 80 weight percent, based on the molecular ~eight of the copolymer. More preferably, these copolymers have an ethylene oxide residue content of from greater than 20 to about 40 weight percent, and most preferably these copolymers have an ethylene oxide residue content of about 30 weight percent. In general, the phosphate ester of the polyoxyethylene/polyoxypropylene copolymer has a propylene oxide residue having a molecular weight of from about 1000 to about 310D. More preferably ~he molecular weight of the propylene oxide residue i~ from ~bout 1500 to about 25Q0, and most preferably the molecular w~ight is about 2000. The concentration ~f the polyoxy-ethylene/polyoxypropylene copolymer in the coolant compo-sition is, in general, from about 0~05 weight percent to about 2 weight percent, based on the weight of th~ neat coolant composition. Preferably the concentration of the copolymer in the coolant is from about 0~1 wei~ht percent to about 0.5 weight percent, neat basis. ~ost preferably the copolymer is present at a level of about 0.2 weight percent, ne2t basis.

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The coolant composition of the presen~ invention may comprise phosphate esters of alkoxyethylate polymers.
ln general, the alkoxyethylate polymers use~ul as corro~ion inhibiting agents in the present invention comprise a linear or branched alkyl moiety having from 6 to 18 carbon atoms, inclusively. More preferably, the alkyl moiety has from 10 ~o i3 carbon atoms, inclusively. These polymers are also well known to those of skill in the artt and can be produced in accordance with methods described in U.S. 4,210l764, which is here~y incorporated by reference. The phosphate es~ers of these polymers may be produced by the general method described in U.S. 3r986,922 which has been herein incorporated by reference. The alkoxyethylate polymers further generally comprise residual ethylene oxide in a~
amount from greater th~n 20 weight percent to about 80 weight percent, based on the molecular weight of the polymer. Preferably the ethylene oxide residue content i~
from greater than 20 weight percent to about 70 weight percent, and most preferably the ethylene oxide residue content is around 62 percent. Generally, the alko~yethylate poly~er is pre~ent in the coola~t composition in an ~mount of from about 0.05 weight percent to about 2 wei~h~ percent, based on the weight ~f nea~ coolane ~ompositionu Prefer-.. ~ . . . . ., . . . . . , . ., . , . . . _ . . .. .. . . . . . . . .

ably, the alkoxyethylate polymer is present in the coolantcomposition in an amount of from about D.l weight percent to about 0.5 weight percent, neat basis. Most preferably, the concentration of the alkoxyethylate polymer in the coolant composition is about 0.2 weight percent, neat ba~is.
In general, the phosphate e~ters of alkylphenol oxyethylate polymers present as corrosion inhibitors in the coolan~ composition of the present invention comprise at least one branched or linear alkyl Moiety having fro~ 4 to 12 carbon atoms, inclusively. More preera~1y, the branched ~r lineax alkyl moieties have from 8 to 10 carbon atoms, inclusively, and most preferably the branched or linear alkyl moieties have 10 carbon atoms therein. The phosphate esters of alkylphenol oxyethylate polymers have either a ~ran~hed or a linear alkyl moiety thereon. ~hese polymers ar~ also well known to those of skill in the art, and can be produced in accordance with methods described in:

M.J. Bchick, "Nonionic Surfactants", pp 57, 58, and 92, ~arcel Dekker, Inc., ~.Y., ~1967) This portion of this publicati~n is h~reby incorporated by reference. The phosphate esters of these polymers may be produced by the general method described in U.~ 3,9~6,922 lB-which has been herein incorporated by reference. Generally, t~e phosphate esters of alkylphenol oxyethylate polymers hdve an ethylene oxide residue content of from about 40 to about 90 weight percent, based on the molecular weight ~f the polymer. Prefera~ly, the phosphate esters of alkyl-phenol oxyethylate polymers have an ethylene oxide re~idue content of from about 54 weight percent to about ~1 weight percent, and most preferably the ethylene oxide residue content is about ~ weight percent. The phosphate esters of alkylphenol oxyethylate polymers are generally pres~nt in the coolant composition at a concentration of from about 0.05 weight percen~ to about 2 weight percent, ~a~ed on the weight of the neat coolant composition. M~st preferably, the concentration of the phosphate e~ters of the alkylphenol oxyethylate polymers is about 0.~ weight percent, baqed on the w~ight of the entixe coolant composition.
In general, the phosphate esters of fatty alcohol heteric ethyleneoxide/propyleneoxide copolymers effective a~
corrosion inhibitors in the coolant composition of the present invention comprise a branched or linear alkyl ~oiety having from 6 to lB carbon atom~, inclusively. ~ore preferably, the branc~ed or linear alkyl moiety has between lD and 16 carbon atoms. The3e polymer~ are al~o well known --}~--,, . , . , . . ~ , .

to those of skill in the art; and can be produced in acco~dance with methods described in U.S. 3,986,922, which is hereby incorporated by reference. The phosphate esters of these polymers may be produced by the general method described in U.S. 3,986,922, which ha~ been herein i~corpor-ated by reference. Most preferably, the branched or linear alkyl moieties present on the fatty alcohol oxyethylate copolymers comprise a blend of alkyl moieties, the moieties having from 12 to 15 carbon atoms, inclusively. F repre-sents the EO fraction in the copolymer~ and F may range from a~out 0.1 to about 0.99. Prefera~ly, ~ i~ from about 0.5 to about 0.9 f and most preferably F is about 0.~5. "n"
repr~sents one size of the heteric block unit. ~enerally, F
and n are together selected so that the copolymer has an EO
content of from greater than 20 to about 95 weight percent, nea~ basis. More preferably, F and n are together ~elected to yield an EO content of about 25 to about 80 weight percent, neat basis. Most preferably, ~ and n are together selected to yield an EO content of about 75 weight percent neat basis. In general, the copoly~er is prese~t in the coolant compo~ition at a concentration o~ ~rom about 0.1 weight per~ent to about 2 weight percent~ ba~ed on the w~ight of the neat coolant co~positionO Preferably the , , ., . .. , . . . .. ,.. ,, _. ~.. . . . . ........ . .

.

concentration of th~ c~polymer is from about 0 2 weight percent ~o 0.4 weight percent, neat basis. Most preferably, the fatty alcohol oxyethylate polymer phosphate ester concentration is about 0.2 weight percent, based on the weight of the neat c~olant composition The coolant composition of the present invention comprises at least one water-soluble li~uid alcohol as a freezing point depressant, in addition to the corrosion inhibitors described above. Furthermore, the coolant composition of the present invention may further comprise ~ny additional compatible additives known to produce .
advantages in anti-freeze formulations.
The above-described corrosion-inhibiting agents may be utilized by themselves ~r in combination with other corrosion-inhibiting agents which are compatible there-with. Each of the corrosion-inhibiting ~gents described above is compatible with the remainder of the corrosion-inhibiting additives described above. ~owever r it i5 ~urther contemplated that any cne or ~ore of the above~
described corrosion-inhibiting agents ~ay be utilized n combina~ion with still further corrosion-inhibiting ~gents which are compatible with the above-described corroæion-inhibiting agents. As used herein, the term "compatibility'~

refers to the preservation of the corrosion-inhibiting result, as well as the preservation of all of the desired ~hemical species present in the coolant composition.
In general, the corrosion inhibiting agents utilized in ~he composition o~ the present invention should be present at a concentration of from about 0.05 weight percent to about 2 weight percent, based on t~e weight of the "neat" (i.e. substantially wa~er-free) compos;tion.
More preferably, the concentration of the agents is between 0.05 weight percent and 0.5 weight percent lon a neat basis), ~nd most preferably the concentration of the agents is between 0.2 weight percent and 0.4 weight percent, on a neat basis. Of course, for diff~rent agents, the optimal concentration is different. The th~oretically opti~al cGncentration is that concentration at which the critical micelle concentration is only slightly exceeded, since it has been found that significant concentration increa es over the critical micelle concentration have a detrimental ~ffect upon corrosion inhibition.
In general, the composition of the pre~ent invention should have a p~ of from about 7 to about 12.
~ost preferably the pH of the composition is ~bout 8.5.
Also, the composition should contain a minimal ~mount of , :

. . .

s ~;
~ ,J~

excess phosphate, ~s excess phosphate has been found to be very agressive (corrosively) against aluminum. As used herein, the phrase "excess phosphate" refers to phosphate which is in excess of that phosphate which is part of the polymeric inhibitor molecule.
As used herein, all of the weight percent figures (~or the EO content, the corro~ion inhibitor concentration, th~ PO content, etc.) are based ~olely on the polymer portion of the molecule, i.e. without consideration for the phosphate portion of the molecule. In other words, the added weight of the phosphate group should not be considered when interpreting the f.igures herein regarding the weight percent EO, wei~ht percent PO, overall molecular weight r and concentration of the inhibitor.
~ he phrase "on a neat basis", as used herein, pertains to the coolant composi~ion with ~ maximum o~ about 5 weight percent water. This small ~mount of water ~prefer-ably only 2 to 3 weight perc~nt) is n~cessary in order to S~olubilize inorganic components in the coolant compo-~ition. Of cour~e, the cool~nt co~position in actual use optimally comprises about 50 weight percent w~ter.
~ h~ coolant composition of the present invention is an agueou~-phase composition. Since the preferred . . .. . . . . . . . . . .

freezing point depressant is a water-~oluble liquid alcohol, (i.e. ethylene glycol), the mo~t preferred concentration of water in the coolant composition is around 50 percent, based on the weight of the total composition.
As has been described in ~he above recitation of the corrosion inhibitors to be utilized in the composition of the present invention, it is both unnecessary and undesireable to utilize a silicate in combination with the corrosion inhibitor. Thus, in contrast to compositions which do not comprise one or more of the above-listed inhibitors, it has been found that 6ilicate should be eliminated as a result of the presence of the corrosion inhibitors described herein. In general, for each of the above-listed corrosion inhibitors, the optimal concentration is from about 0.05 weight percent to about 2 weight percent, based on the weight of the neat composition.
A first preferred coolant composition comprises a corrosion inhibitor which is a phosphate ester of an ethylene diamine initiated polyo~yethylene~polyo~ypropylene copolymer, the copolymer being at least one member ~elected from the group consisting of block copolymer~ and heteric copolymers t the copolymer having the following g~neral formula:

, .. ... . . , . . ~

~J ~ f, ,J ~

P04 - (EO)y ~ (P)X / (PO)x ~ (EO)y _ po4 2 ~ NC2H4N ~
P04 - lEQ)y ~ (P~)x (P~)x (EO)y _ pO4 2 ~herein Y is selected so that the total weight percent of EO
is about ~0, based on the molecular weight of the copolymer, and wherein X is selected ~o that the molecular weight of the PO in the copolymer is about 4833, and wherein the ooncentration of the copolymer is from about 0.05 weight percent to about 0.3 weight percent based on the weight of the neat composition.
A second preferred coolant composition is identical to the f irst pre~erred coolant composition described immediately above, except that Y is ~elected so that ~:he total weight percent EO in the ~opol3mer i~ abou~
30, based on the molecular weight of the copolymer, ~nd X is selected ~o that the molecular weight o~ the PO in the copolymer i~ about 5900.
A third preferred coolant oo~pvsition i8 identical to ~be firs~ preferred coolant composition de~cribed above, except that Y is ~elected BQ ~hat ~he ~o~l wei~ht percen~

. ~, .. , ,.. , . _ . . . ... , . , , . . . ~ , .

of EO in the copolymer is about 40, and X i~ selected ~o that the molecular weight of the PO in the copolymer is about 4830, and the concentration of the copolymer in the composition is about O.S weight percent, based on the weight of the neat composition.
A fourth preferred coolant composition is identical to the first preferred composition described above, except that Y is selected so that the total weight percent of EO in the copolymer is about 40, and X is selected so that the molecular weight of the P~ in the copolymer is about 5910, and the concentration of the copclymer in the composition is between about 0.1 and about 0.~ weight percent, based on the weight of the neat compo~

sition.
A fifth preferred coolant composition i~ identical to the first preferred coolant ~omposition described above, except that Y is selected ~o that the total weight percent of EO in the copolymer is about 40, based on the molecular weight of the copolymer and X i8 ~elec~ed 60 that the molecular weight of ~he PO in the copolymer is ~bout 3750, and the concentration of the copolymer in the composition is about 0.5 weight percent, ba~ed on the weight of ~he nea~
co~posiion.

-2~-._ . . .. . .......... . . ......... .... ........ .. ... . ... .

A sixth preferred coolant composition comprises a phospha~e ester of a polyoxypropylene/polyoxyethylene copolymer corrosion inhibitor, which copolymer i~ at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer being of the following general formula:

P4 ~ (~)y ~ (PO)X ~ (EO~y - PO4 wherein Y is selected 50 that the total weight percent of EO
in the copolymer is about 40, and wherein X is selected ~o that the molecular weight of the PO in the ~opolymer i~
about 1970. ~urthermore, the concentration of the polyoxy e~hylene/polyoxypropylene copolymer in the coolant compo-sition is from about 0.05 weight percent to about 0.5 weight percent, based on the weight of the neat composition.
A seventh preferred coolant compo~ition is identical to the the ~ixth preferred coolant composition, excep~ that X is ~elec~ed 50 that the total weight percent EO in the copolymer is about 40 r and X is selected ~o that the molecular weight of the PO in the copoly~er i~ a~out .. . , . . , . .; .. . . . . . . . . . . . .. .. . . ...

;J ~ i I J

1290, and wherein the concentration of the copolymer in the composition is from about 0.05 weight percent to about 0.5 weight percent.
An eighth preferred coolant composition is identical to the sixth preferred coolant composition~ except that Y is selected so that the total weight percent E0 in the copolymer is about 20 and X is selected ~o that the molecular weight of P0 in the copolymer i~ about 1970, and the concentration of the copolymer in the composition is about 0.5 weight percent.
A ninth preferred coolant composition comprises a corrosion inhibitor which is a phosphate ester polyoxy-ethylene/polyoxypropylene copolymer, which copolymer comprises at least one member ~elected from the group consisting of block copolymers and heteric copolymers, the copolymer being of the following general formula:

-20 P - ~P)X ~ (EO)y ~ (PO)x P4 -2~-wherein X is selected BO that the total molecular weight of the PO in the copolymer i5 about 2570, and wherein Y is selected so that the weight percent EO in the cop~lymer is about 20, based on the molecular weight of the copolymer.
The phosphate ester of the polyoxyethylene/polyoxypropylene copolymer is present in the composition in an amount ~rom about 0.05 weight percent to about O.S weight percent, based on the weight of the neat composition.
A tenth preferred coolant composition comprises a phosphate ester of a fatty alcohol heteric oxyalkylate copolymer of the following general formul~:

R - O [(PO)F , (EO¦ ] - PO~ ~

wherein the weight percent EO in the copolymer i8 about 68, and wherein the weight percent PO in the m~lecule is about 1~ weight percent, and wherein the mole~ule h~s a molecular weight of ~bout 820. ~urther~ore, the ~opDlymer is present in the composition in an amount from about 0.2 to about 0.4 wei~ht percent, base~ on the wei~ht of the neat co~po~ition.

--;29--An eleventh preferred coolant composition, this composition being identical to the tenth preferred compo-sition, except that the phosphate ester of the fatty alcohol heteric polyoxyethylene/polyoxypropylene copolymer has a weight percent EO of about 25 based on the molecul~r weight of the molecule, and a weight percent PO of about 50, based on the molecular weight of the molecule, and wherein the molecule has ~ molecular weight of about 820.
A twelfth preferred coolant composition which is iden~ical to the tenth preferred coolant composition, except that the heteric polyethylene oxide/polypropylene oxide polymer has a weight percent EO of about 40, based on the molecular weight of the molecule, and the copolymer has a weight percent PO of about 27, based on the molecular weight of the molecule, and wherein the molecular weight of the molecule is about 625.
A thirteenth preferred coolant compo~ition i~
identical to the tenth preferred coolant compo~ition, except that the fatty alcohol heteric polyethyleneoxide~poly propyleneoxide polymer has a weight percent EO of about 47, based on the molecular weight of the molecule, and the copolymer has a wei~ht perce~t PO o~ about 31 ba~ed pn the molecular weight of the molecule, and the molecular weight of the molecul~ i~ about 930.

A fourteenth pref~rred cn~lant composition comprises an alkyethylate polymer of the following general formula:

R - O - ~EO)y _ po4 2 wherein R - O - is a decylalcohol re~idue and wherein Y has an average value of about 6, and wherein the concentration of the polymer in the coolant is about 0.2 weight percent, on a nea~ basis. ~urthermore, the concentration of the polymer in the composition is from about 0.1 weight percent to about 0.5 weight percent, based on the weight of the neat composition.
A fifteenth preferred csolant composition is identical to the fourteenth coolant composition, except that Y has an average value of about 9.
A sixteenth preferred coolant compo~ition i~
identical to the ~o~rteenth pre~erred coolant compo~ition, e~cept that ~ - O - is a tridecylalcohol residuet ~nd wherein Y has an average value of about 8.

... . ..... . . ..

S~ 5 ~J~' '~ ~;/

A seventeenth preferred coolant composition comprises a alkylphenol oxyethylate polymer of the following general formula:

R - ~ - O - (EO~y - po4 2 wherein R is an alkyl group having eight carbon atoms thereon, and wherein Y has an average value of about 10, and wherein the concentration of the polymer in the coolant is from about 0.05 weight percent to about 0~5 weight percent, based on the weight of the neat composition, Nethod for Determining Degree o~ Corrosion Inhibition The above-identified corrosion ~nhibition agents were evaluated to determine the degree to which they affected corrosion inhlbition. A galvano~tairca~e polar-ization method was utilized for this evaluation. ~alvano-s~aircase polari2ation i~ described in the Pollowing, publications:

1. S.~. ~irowawa, "Corrosion Moni~oring by Galvanostaircase Polarization", p. 321 in ELECTRO-CHEMICAL TECHNIQUES FOR COP~ROSION ENGINEE~ING, edited R. Baboian, NACE, ~ouston (1986).
2. ASTM G100~89, "Standard ~est ~ethod for Conducting Cyclic Galvanostaircase Polasization", 19 8 9 ANNUAL BOOK OF ASTM STANDARDS, ASTM, Philadelphia, (1989) ...... . .. .. ...... ..

The above references are herein incorporated by reference.
The galvanostaircase polarization apparatus consisted of a recording device (recorder, printer or plotter), a p~lar-ization cell and a potentiostat which was capable of outpu~ing a current staircase signal. The polarization cell consisted of saturated calomel reference electrode, a pair of graphite counter electrod~s and a working electrode of 3003 wrought aluminum held in a flat specimen holder. One square centimeter of the aluminum was exposed to the solution. Upon carrying out the galvanostaircase p~lar-ization, if the voltage rises immediately when the first current step is applied, the media is effective in pass-ivating the aluminum. However, if the media is non-pass-ivating or slowly- or poorly- passivating, there is no initial rise in the voltage relative to the corrosion potential [ECorr)~ but the voltage may b~gin to rise at ~ome higher current level. In very corrosive media, no ri~e in volt~ge is observed up to B00 to 1,000 uA/cm2, which are arbitrary limits of the experiment. The passivation current iipaSS.n) is obtained by extrapolating the ~teepest part of the curve to Ecorr .. . . . . . ..

A base ooolant (s~lution A) was prepared having the following composition:

Ethylene glycol, AF GRADE 95.44%
Water 2.00%
Borax 5 H~O 2.00%
HNO~ (70.5%) 0O263 NaN~2 0.10%
Na Tolyl triazole 550%) 0.20 NaOH as re~uired The galvanostaircase polarization method was applied to the above-base coolant (i.e. solution A). The aluminum ~howed no sign of passivation in solution at 180F (82C) (and at a ~1 cf 8.5) as deduced from the observation that the pass-ivation curren~ was greater than 800 uA/cm2 [See Figure 1). Figure 1 shows the effect of the ~ilicate level on the passivation current of aluminum. A second bas~ coolant (~lution B~ was made up according to the formulation o solution A, e~cept that just enough silicate was added in order to produce a pas~ivation current of 0 (5ee ~igure everal potential corrosion inhibiting agents were ~creened in order to determine whether these age~ts have a p~sitive corro~ion inhibition effect when utili~ed in the pre~ence of ~ilica~e. A large batch of a Referenoe ~e~t Solution w~s pr~pared by combining 65 parts of solution B

-3~-... .

, ~ t,, ~,J, . ~ , "J

and 35 parts of solution A. The re6ulting mixture exhibited a passivation current at around the mid-point (i.e. at 387 uA/cm2) of the highly silica-dependent portion of the curve illustrated in Figure 1. The corrosion inhibitors were then added to this reference test solution, and the change in passivation current, if any, was de~ermined. If the addition of the potential corrosion inhibitor lowered the passivation current relative to the reference passivation current ~i.e. if the passivation current of the solution comprising the inhibitor was less than 387 uA~cm2), the corrosion inhibiting additive was deemed to b~ "synergistio"
with silicate. It is prefer~ed to select a polymer which is low foaming, high wetting, and which has a relatively high water solubility, when making the co~positions of the present invention. Furthermore, it is believ~d that a higher passivation current corresponds with a lowering of the corrosion inhibition. It is believed that a lower passivation current corresponds with a greater degree of corrosion inhibition. On the other hand, if the pa~ivation current of the test solution containing the potential corrosion inhibiting agent was found to be higher ~han the refer~nce te~t solution value of 3B7 uA/cm2,.the agent was deemed to be ~antisynergi~tic".

., . .. . . ., . , ,, . ~ , . . .

Table I provides results which indicate the various degrees to which various agent~ impart a lowering or raising of the passivation current when added to the reference test solution. As can be ~een in Table I, a phosphate ester of a fatty acid heteric ethyleneoxide/-propyleneoxide copolymer inhibition agent was tested to see whether they were inhi~iting or non-inhibiting. As can easily be seen in Table 1, most of the ~gents were found to be significantly inhibiting only when present in the absence of silica, but were found to be highly non-inhibiting when utilized in the presence of silicates.

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The Pump Test A standard test method was ca~ried out for testing cavitation errosion-corrosion of an aluminum automotive coolant pump. This method is describe~ in the following publication:

~STM D 2809-83, "Standard Test ~ethod ~or Cavitation ~rrosion-Corrosion Characteristic oF
Aluminum Pumps With Engine Coolants", 1988 ANNUAL
BOOK 0~ ASTM STANDARDS, ASTM, Philadelphia, (1988).
The above article is herein incorporated by reference for the purpose of enabling the pump test. ~he cavitation errosion-corrosion aluminum pump test was, in general, carried out in a manner substantially equiv~lent t~ the method described in the above ASTM publication. The r~ference coolant solution utilized in the testing was the same as Solution A, described above. Table II provides the results of the pump test. As can be seen, the addition of 0~2 weight percent of a pho~phate ester of an ethylene diamine initiated polyoxyethylene/polypropylene copolymer ~having about 30 weigh~ percent EO, and a PO molecular weight of about ~900) produced signi~icantly les~ pump cavitation corrDsion than a refer~nce coolant ~olution which was identical except for its absence of ~hi~ org~nic .. ~ . . . .. . .. . ... . .. ... . . . . . . .

~ ' t ~/J ~ 'J

inhibitor. In fact, the addition of the copolyme~ corrosion inhibition agent permitted the pump to run three times as long as the control and exhibit ~ubstantially less wear than the control. Thus, the results of Table II indicate the desirability of the coolant compo itions of the present invention.

Table II
Pump Test Results Weight PeroentNo ~rs. ASTM W¢ar Coolant CompositionPolymeric Inhibitor Run . Ratin~ _ .
Solution A (described --- 100 6.8 supra) (CONTROL) Solution A plus polymeric 0.4 600 8 D 8 inhibitor *

*The phosphate ester polyme~ic inhibitor was a pho~phate ~ster of a fatty acid heteric ethyleneoxide/pr~pyleneo~ide copolymer of formula R-O- [(PO)~ , ~EO)l_~ ]-P~4~ whe~ei~
the weight percent of EO wa~ about 68, the weight percent ~O
was about 58, the weight percent PO was about 12, and ~he weight percent ~f the R group was about 20.

--~0--.. . . ... .... .. ... . . . ... . . . .

Claims (20)

We claim:

1. A silicate-free coolant composition which comprises at least one corrosion inhibitor, wherein the corrosion inhibitor comprises at least one member selected from the group consisting of:
(A) a phosphate ester of an ethylene diamine initiated polyoxyethylene/polypropylene copolymer, the copolymer being at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer having the following general formula:

wherein "EO" represents an ethylene oxide residue, while "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent of EO in the copolymer is from greater than 20 to about 40, based on the molecular weight of the copolymer; wherein X is selected so that the molecular weight of the PO in the copolymer is from about 1500 to about 7500, and wherein the concentration of the copolymer in the composition is between about 0.05 percent and about 2 percent, based on the weight of the neat composition;

(B) a phosphate ester of a polyoxypropylene/poly-oxyethylene copolymer, which copolymer is at least one member selected from the group consisting of block copoly-mers, heteric copolymers, and heteric/block copolymers, the copolymer being of the following general formula:

wherein "EO" represents an ethylene oxide residue, and wherein "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent of EO
in the organic portion of the copolymer is from greater than 20 to about 80 percent, and wherein X is selected so that the molecular weight of the PO in the copolymer is from about 950 to about 4000, and wherein the concentration of the phosphate ester of the polyoxyethylene/polyoxypropylene copolymer in the coolant composition is from about 0.05 weight percent to about 2 weight percent, based on the weight of the neat composition;

(C) a phosphate ester of a polyoxyethylene/-polypropylene copolymer, which copolymer is at least one member selected from the group consisting of block copoly-mers and heteric/block copolymers, the copolymer being of the following general formula;

wherein "EO" represents an ethylene oxide residue and wherein "PO" represents a propylene oxide residue, and wherein X is selected so that the total molecular weight of the PO in the copolymer is from about 1,000 to about 3,100, and wherein Y is selected so that the weight percent of the EO in the copolymer is from greater than 20 to about 80, based on the molecular weight of the copolymer, the copoly-mer being present in the composition in an amount from about 0.05 weight percent to about 2 weight percent, based on the weight of the neat composition;
(D) a phosphate ester of an alkoxyethylate polymer of the following general formula:

wherein R is at least one member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R has from 6 to 18 carbon atoms, and wherein "EO" represents a residual ethylene oxide moiety, and wherein the alkyloxyethylate polymer has an average molecular weight of from about 200 to about 3000, and wherein the alkyloxyethylate polymer has an ethylene oxide residue content of from greater than 20 to about 80 weight percent, based on the molecular weight of the polymer, and wherein the concentration of the polymer in the composition is from about 0.05 weight percent to about 2 weight percent, based on the weight of the total composition;

(E) a phosphate ester an alkylphenol oxyethylate polymer of the following general formula:

wherein R is a member selected from the group consisting of branched alkyl moieties and linear alkyl moieties, wherein R
has from 4 to 12 carbon atoms, and wherein EO represents a residual ethylene oxide moiety, and wherein the polymer has an ethylene oxide residue content of from about 40 to about 90 weight percent, based on the molecular weight of the polymer, and wherein the concentration of the polymer in the composition is from about 0.05 to about 2 weight percent, based on the weight of the neat composition;
(F) a phosphate ester fatty alcohol heteric ethyleneoxide/propyleneoxide copolymer of the following general formula:

wherein R is a member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R
has from 6 to 18 carbon atoms, and wherein EO represents a residual ethylene oxide moiety, and wherein PO represents a residual propylene oxide moiety, and F has a value of from 0.1 to 0.99, and wherein F and n are selected so that the copolymer has an EO content of from greater than 20 to about 95 weight percent, and wherein the copolymer is present in the composition in an amount from about 0.1 to about 2 weight percent, based on the weight of the neat composition, Wherein one or more of the members of the above group of inhibitors, as well as the concentration of the inhibitors, are selected so that the resulting liquid composition exhibits a passivation current which is less than a standard reference composition.

2. A silicate-free coolant composition as described in claim 1 wherein the coolant composition comprises at least one corrosion inhibitor, the corrosion inhibitor comprising at least one member selected from the group consisting of:
(A) a phosphate ester of an ethylene diamine initiated polyoxyethylene/polypropylene copolymer, the copolymer being at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer having the following general formula:

wherein Y is selected so that the total weight percent of EO
in the copolymer is from greater than 20 to about 40, based on the molecular weight of the copolymer, wherein X is selected so that the molecular weight of the PO in the copolymer is from about 1500 to about 7500, and wherein the concentration of the copolymer in the composition is between about 0.05 percent and about 0.5 percent, based on the weight of the neat composition;
(B) a phosphate ester of a polyoxypropylene/poly-oxyethylene copolymer, which copolymer is at least one member selected from the group consisting of block copoly-mers and heteric/block copolymers, the copolymer being of the following general formula:

wherein Y is selected so that the total weight percent of EO
in the neat composition is from greater than 20 to about 40 percent, and wherein X is selected so that the molecular weight of the PO in the copolymer is from about 1100 to about 2000, and wherein the concentration of the phosphate ester of the polyoxyethylene/polyoxypropylene copolymer in the coolant composition is from about 0.05 weight percent to about 0.5 weight percent, based on the weight of the neat composition;
(C) a phosphate ester of a polyoxyethylene/poly-propylene copolymer, which copolymer is at least one member selected from the group consisting of block copolymers, and heteric copolymers, the copolymer being of the following general formula:

wherein X is selected so that the total molecular weight of the PO in the copolymer is from about 1,500 to about 2,500, and wherein Y is selected so that the weight percent of the EO in the copolymer is from greater than 20 to about 30, based on the molecular weight of the copolymer, the copolymer being present in the composition in an amount from about 0.05 weight percent to about 0.5 weight percent, based on the weight of the neat composition;
(D) a phosphate ester of an alkoxyethylate polymer of the following general formula:

wherein R is at least one member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R has from 10 to 13 carbon atoms, and wherein the alkyloxyethylate polymer has an average molec-ular weight of from about 200 to about 1000, and wherein the alkyloxyethylate polymer has an ethylene oxide residue content of from greater than 20 to about 70 weight percent, based on the molecular weight of the polymer, and wherein the concentration of the polymer in the composition is from about 0.1 weight percent to about 0.5 weight percent, based on the weight of the neat composition;
(E) a phosphate ester of an alkylphenol oxy-ethylate polymer of the following general formula:

wherein R is a member selected from the group consisting of branched alkyl moieties and linear alkyl moieties, wherein R
has from 8 to 10 carbon atoms, and wherein EO represents a residual ethylene oxide moiety, and wherein the polymer has an ethylene oxide residue content of from about 54 to about 81 weight percent, based on the molecular weight of the polymer, and wherein the concentration of the polymer in the composition is from about 0.1 to about 0.5 weight percent, based on the weight of the neat composition;
(F) a phosphate ester of a fatty alcohol heteric ethyleneoxide/propyleneoxide copolymer of the following general formula:

wherein R is a member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R
has from 10 to 16 carbon atoms, and wherein F has a value of from about 0.5 to about 0.9, and wherein F and n are together selected to yield a weight percent EO in the polymer of from about 25 to about 80, and wherein the fatty alcohol oxyethylate copolymer is present in the composition in an amount from about 0.2 to about 0.4 weight percent, based on the weight of the neat composition;

Wherein one or more of the members of the above group of inhibitors, as well as the concentration of the inhibitors, is selected so that the resulting liquid composition exhibits a passivation current which is less than a standard reference composition.

3. A silicate-free coolant composition as described in claim 1 wherein the coolant composition comprises at least one corrosion inhibitor, the corrosion inhibitor comprising at least one member selected from the group consisting of:
(A) a phosphate ester of an ethylene diamine initiated polyoxyethylene/polyoxypropylene copolymer, the copolymer being at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer having the following general formula:

wherein "EO" represents an ethylene oxide residue, while "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent of EO in the copolymer is from greater than 20 to about 40, based on the molecular weight of the copolymer, wherein X is selected so that the molecular weight of the PO in the copolymer is from about 1500 to about 7500, and wherein the concentration of the copolymer in the composition is about 0.2 percent, based on the weight of the neat composition;
(B) a phosphate ester of a polyoxypropylene/poly-oxyethylene copolymer, which copolymer is at least one member selected from the group consisting of block copoly-mers and heteric copolymers, the copolymer being of the following general formula:

wherein "EO" represents an ethylene oxide residue, and wherein "PO" represents a propylene oxide residue, and wherein Y is selected so that the weight percent of EO in the copolymer is about 30 percent, and wherein the molecular weight of the PO in the copolymer is about 1620; and wherein the concentration of the polyethylene/polypropylene copoly-mer in the coolant composition is about 0.2 weight percent, based on the weight of the neat composition.
(C) a phosphate ester of a polyoxyethylene/poly-oxypropylene copolymer, which copolymer is at least one member selected from the group consisting of block copoly-mers, heteric copolymers, the copolymer being of the following general formula:

wherein "EO" represents an ethylene oxide residue and wherein "PO" represents a propylene oxide residue, and wherein X is selected so that the total molecular weight of the PO in the copolymer is about 2,000 and wherein the weight percent of the EO in the copolymer is about 30, based on the molecular weight of the copolymer;

(D) a phosphate ester of an alkoxyethylate polymer of the following general formula:

wherein R is at least one member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R has from 10 to 13 carbon atoms, and wherein "EO" represents a residual ethylene oxide moiety, and wherein the alkyloxyethylate polymer has an average molecular weight of about 420, and wherein the alkyloxy-ethylate polymer has an ethylene oxide residue content of about 62 weight percent, based on the average molecular weight of the polymer; and wherein the concentration of the polymer in the coolant composition is about 0.2 weight percent, based on the weight of the neat coolant compo-sition.
(E) a phosphate ester of an alkylphenol oxy-ethylate polymer of the following general formula:

wherein R is a member selected from the group consisting of branched alkyl moieties and linear alkyl moieties, wherein R
has 10 carbon atoms, and wherein EO represents a residual ethylene oxide moiety, and wherein the polymer has an ethylene oxide residue content of about 68 weight percent, based on the molecular weight of the polymer, and wherein the concentration of the polymer in the composition is about 0.2 weight percent, based on the weight of the neat compo-sition;
(F) a phosphate ester of a fatty alcohol heteric ethyleneoxide/propyleneoxide copolymer of the following general formula:

wherein R is a member selected from the group consisting of linear alkyl moieties and branched alkyl moieties, wherein R
represents alkyl groups having 12 to 15 carbon atoms, and wherein F has a value of about 0.85, wherein F and n are together selected to yield a weight percent EO in the polymer of about 75, and wherein the copolymer is present in the composition in an amount of about 0.2 weight percent, based on the weight of the neat composition;

4. A coolant composition as described in claim 2 wherein the corrosion inhibitor is a phosphate ester of an ethylene diamine initiated polyoxyethylene/polyoxypropylene copolymer, the copolymer being at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer having the following general formula:

wherein "EO" represents an ethylene oxide residue, while "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent of EO is about 30, based on the molecular weight of the copolymer, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 4833, and wherein the concentration of the copolymer is from about 0.05 weight percent to about 0.3 weight percent, based on the weight of the neat composition.

5. A coolant composition as described in claim 4, wherein Y is selected so that the total weight percent of EO
in the copolymer is about 30, based on the molecular weight of the copolymer, and wherein X selected so that the molecular weight of the PO in the copolymer is about 5900.

6. A coolant composition as described in claim 4, wherein Y is selected so that the total weight percent of EO
in the copolymer is about 40, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 4830, and wherein the concentration of the copolymer in the composition is about 0.5 weight percent, based on the weight of the neat composition.

7. A coolant composition as described in claim 4, wherein Y is selected so that the total weight percent of EO
in the copolymer is about 40, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 5910, and wherein the concentration of the copolymer in the composition is between about 0.1 and about 0.5 weight percent, based on the weight of the neat composition.

8. A coolant composition as described in claim 4 wherein Y is selected so that the total weight percent of EO
in the copolymer is about 40, based on the molecular weight of the copolymer, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 3750, and wherein the concentration of the copolymer in the composition is about 0.5 weight percent, based on the weight of the neat composition.

9. A coolant composition as described in claim 2, wherein the composition comprises a phosphate ester poly-oxypropylene/polyoxyethylene copolymer corrosion inhibitor, which copolymer is at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer being of the following general formula:

wherein "EO" represents an ethylene oxide residue, and wherein "PO" represents a propylene oxide residue, and wherein Y is selected so that the total weight percent of EO

in the neat composition is about 40, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 1970.

10. A coolant composition as described in claim 9, wherein Y is selected so that the total weight percent EO in the neat composition is about 40, and wherein X is selected so that the molecular weight of the PO in the copolymer is about 1290, and wherein the concentration of the copolymer in the composition is from about 0.05 weight percent to about 0.5 weight percent.

11. A coolant composition as described in claim 9, wherein Y is selected so that the total weight percent EO in the copolymer is about 20, and wherein X is selected so that molecular weight of PO in the copolymer is about 1970, and wherein the concentration of the copolymer in the compo-sition is about 0.5 weight percent.

12. A coolant composition as described in claim 2, wherein the corrosion inhibitor is a polyoxyethylene/poly-oxypropylene copolymer, which copolymer comprises at least one member selected from the group consisting of block copolymers and heteric copolymers, the copolymer being of the following general formula:

wherein "EO" represents a ethylene oxide residue and wherein "PO" represents a propylene oxide residue, and wherein X is selected so that the total molecular weight of the PO in the copolymer is about 2570, and wherein Y is selected so that the weight percent EO in the copolymer is about 20, based on the molecular weight of the copolymer, and wherein the copolymer is present in the composition in an amount from about 0.05 weight percent to about 0.5 weight percent, based on the weight of the neat composition.

13. A coolant composition as described in claim 2, wherein the coolant composition comprises a phosphate ester of a fatty alcohol heteric oxyalkylate copolymer of the following general formula:
wherein the weight percent "EO" in the copolymer is about 68, and wherein the weight percent "PO" in the molecule is about 12 weight percent, and wherein the molecule has a molecular weight of about 820, and wherein the copolymer is present in the composition in an amount from about 0.2 to about 0.4 weight percent, based on the weight of the neat composition.

14. A coolant composition as described in claim 13, wherein the fatty alcohol heteric polyethyleneoxide/-polypropyleneoxide copolymer has a weight percent EO of about 25, based on the molecular weight of the molecule, and a weight percent PO of about 50, based on the molecular weight of the molecule, and wherein the molecule has a molecular weight of about 820.

15. A coolant composition as described in claim 13, wherein the fatty alcohol heteric polyethyleneoxide/-polypropyleneoxide polymer has a weight percent EO of about 40, based on the molecular weight of the molecule, and wherein the copolymer has a weight percent PO of about 27, based on the molecular weight of the molecule, and wherein the molecular weight of the molecule is about 625.

A coolant composition as described in claim 13, wherein the fatty alcohol heteric oxyethylate polymer has a weight percent EO of about 47, based on the molecular weight of the molecule, and wherein the copolymer has a weight percent PO of about 31, based on the molecular weight of the molecule, and wherein the molecular weight of the molecule is about 930.

17. A coolant composition as described in claim 2 wherein the coolant composition comprises an alkoxyethylate polymer of the following general formula:

wherein R - O - is a decylalcohol residue and wherein Y has an average value of about 6, and wherein the concentration of the polymer in the coolant is about 0.2 weight percent, neat basis, and wherein the concentration of the polymer in the composition is from about 0.1 weight percent to about 0.5 weight percent, based on the weight of the neat compo-sition.

18. A coolant composition as described in claim 17 wherein Y has an average value of about 9.

19. A coolant composition as described in claim 17 wherein R - O - is a tridecylalcohol residue and wherein Y
has an average value of about 8.

20. A coolant composition as described in claim 2 wherein the coolant composition comprises an alkylphenol oxyethylate polymer of the following general formula:

wherein R is an alkyl group having 8 carbon atoms thereon and wherein Y has an average value of about 10, and wherein the concentration of the polymer in the coolant is from about 0.05 weight percent to about 0.5 weight percent, neat basis.