CA2017014A1

CA2017014A1 - Compositions and process for improved preparation of metals for cold forming

Info

Publication number: CA2017014A1
Application number: CA002017014A
Authority: CA
Inventors: Paul A. Kulongowski
Original assignee: Henkel Corp
Current assignee: Henkel Corp
Priority date: 1989-05-18
Filing date: 1990-05-17
Publication date: 1990-11-18
Also published as: JPH02305897A; CN1047331A; ZA903494B; EP0398201A1; AU624710B2; BR9002320A; AU5507390A

Abstract

Abstract of the Disclosure Reactive lubrication of phosphated metal surfaces is improved by using a combination of (A) a complexing agent for the divalent metal cations that are displaced from the phosphated layer into the lubricating solution and (B) organic molecules having at least one ether or hydroxyl oxygen for each eight carbon atoms, along with the conventional soluble soap, in the solution used for reactive lubrication. Most preferably, EDTA or its salts are used as the complexing agent and polyethylene glycol as component (B), with the concentration of EDTA being adjusted as needed during the process to keep the concentration of total titratable metals in the lubricating solution below 0.05 % by weight, and the amount of polyethylene glycol being adjusted as needed to maintain the optimum viscosity of the lubricating solution and optimum ratios of reactive to unreacted lube coating weights and of reacted lube coating weight to conversion coating loss.

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Description

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COMP08ITION8 I~D PROCEk~E;X8 FC)R INPRO'VED PRE~PARATION OF
~ .a FOR C~L~ Fo~qI~aa Fi~ld of the Invention The present inYention rela~es to co~positions and methods ~or lubricating phosphated metal surfaces prior to drawing or other cold forming processes on the lubricated ~etal.
Statement of Xelated Art It has been known for many years to prepare metals for cold for~ing by phosphatin~ followed by lubrication with a soap or si~ilar materlal. Generally, phosphating from solutions that contain zinc ionsj and som~times also contain c~lcium, nickel, ~anganese, copper, and/or other dival~nt metal ions, is preferred as ~he phosphating step.
An aqueous solution oP alkali ~etal soap, capable of reacting with zinc phosphat~ to produce a ve~y f~vorable for~ of zinc stearat~ called "reacted lube" in situ on th~
surface, is generally preferred for the lubrication stage.
Initi~lly, a simpl~ solu~ion o~ r~active ~oap in water provides very e~fective lubrica~ion. The lubrication pro-c~s~, however, is known ~o cause dissolution o~ part of the phosphate coating. For thi~ a~d possibly other reasons, dival~nt metal io~s accumulate in the lubricating solution , , ~70~4 as the process proceeds and eventually cause the lubricating coatings formed to become unsatisfactory.
United States Patent 4,199,381 of April 22, 1980 to Nuss et al. teaches that, when lubricating surfaces formed in phosphating baths containing divalent metal ions that are incor-porated into the phosphate coating formed, the results can be improved by incorporating complexing agents for such divalent ions into the lubricating solutions (see in particular column 1 line 10 to column 2 line 4; column 2 lines 33 - 49; and column 3 lines 6 - 11).
Complexing agents as taught by Nuss are highly effec-tive in increasing the useful life of lubricating solutions and in promoting usefully high coating weights of lubricant, but prolonged use of these complexing agents eventually results in increased lubricating solution viscosity, increased dissolu-tion of the phosphate coating into the lubricating solution, drying problems, reduced lubricant adhesion, and higher propor-tions of less desirable l'unreacted" lubricant in the lubricant coating formed. It is an object of the present invention further to improve the processes and compositions described by Nuss in order to ameliorate these difficulties.
United States Patent 3,556,996 of January 19, 1971 to Jones et al. teaches the use of surfactants, including con-densates of alcohols with ethylene oxide, in lubricating solutions, along with sugar and/or polyethylene glycol as optional components.

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Descri tion of the Invention P
In this description, except in the operating examples or where expressly stated to the contrary, all numbers describing amounts of materials or conditions of reaction or use are to be understood in all instances as modified by the word "about".
It has been found that large amounts of complexing - 2a -~7~ ~
agents can b harmful to the reactive lubrication process after phosphating, so that better results are obtained by observing an upper limit on the concentration of complexing agent present, he upper limit beiny connected with the amount of complexable, divalent cations introduced into the lubricating solution during use. It has also been found that the reactive lubrication process can be improved by using aqueous lubricating solutions that, in addition to soluble metallic soaps having aliphatic anions with 8 to 22 lo carbon atoms and hydrolysis resistant complexing agents as taught by Nuss, contain water soluble or dispersible organic compounds that are stable in solution or dispersion under normal conditions of applying lubricant to phosphated surfaces and that contain at least one hydroxyl or ether oxygen for each eight carbon atoms. This lattsr component is referred to briefly hereinafter as "oSoC" (for 'loxygen-ated soluble organic compound"). In the definition of the oSoc component, neither oxygen atom of a carboxyl or car-boxylate group is considered to ~e an ether or hydroxyl oxygen. Preferably, the OSOC component molecules contain at least one hydroxyl or ether oxygen for each two carbon atoms.
The water soluble soap to be used in this invention may be any material known for such a use in the art, including technical sodiu~ ~tearate containing from 40 to 90 % of Cla soaps, as used in sonne examples of the Nuss patent noted above, but technical mixtures including a higher proportion of sodium stearate are generally most highly preferred. ~he complexing agent similarly may be any material known as such in th~ art, but preferably is selected from the group consisting of ethylene diaminetetraacetic acid (hereinafter "EDT~") and its salts, nitrilotriacetic acid (hereina~ter IlNTAn) and its salts, N
hydroxyethylethylene diaminetriacetic acid ~hereinafter "NEDTA") and its salts, diethylene triamine pentaacetic acid and it~ salt~, diethanol glycine, and a material having CAS Registry No. 68611-02-9* and described by its 2 ~

manu~acturer a~ "glycine,N,N'-1,2-ethanediylbis[N-carboxymethyl) , reaction products with citric acid, D-gluconic acid, and triethanolamine, sodium salt." EDTA
and its salts are most preferred.
The OSOC component is preferably selected from the group consisting of alkylene glycols, polyalkylene glycols, glycol ethers, ethoxylated alcohols, polymers and copolymers of ethylene oxide and propylene oxide, and glycerin.
For ~oth the complexing agent and the OSOC component, mixtures of materials from the preferred group are equally as preferred as single chemical types of materials, unless otherwise noted.
Poly(ethylene glycol), hereinafter 'IPEG'', is more prefexred than other OSOC materials, with PEG having a molecular weight of about 4000, hereinafter "PEG 4000", being most pre~erred. When the OSOC component consists essentially of PEG 4000, it is preferred that the ratio of the concentration of the complexing agent to the concentra-tion o~ the OSOC component lie within the range of 1 - 5, more preferably within the range of 2.5 to 3.5, and most preferably within the range o$ 2.9 - 3.1.
It is ~preferred that the concentration of reactive soap in the solutions according to l:he inventi~n lie within the range of 5 to 150 g/L of solution. The preferable concentrations o~ complexing age!nt are determined by balancing several consid~rations, as noted further below.
A process embodiment o~ this invention may be per-formed by contacting a suitable phosphated surface with a lubricating solution according to the invention, as gener-ally d2scribed above. It is beli~ved that there is no advantage from the presence of the complexing agent in ~he vçry early stages o~ use of a Preshly prepared lubricating solution, before any significant amounts of divalent metal ions have accumulated in the lubricating solution a8 a result of its exposure to a phosphated surface. HoweverJ
it ha6 been found that there is no apparent harm Pro~ an 2~7~ ~

initial concentration o complexing agent as high as 0.1 gram per liter ~hereinafter "g~LI'~, and th~ use of 801u-tions initially made up to contain about thi6 amount, or slightly less, of complexing agent is generally preferred in pra~tice, in order to avoid the need to add complexing agent within a relatively s~ort time after a fresh lubri-cating solution has been put in~o use.
An ideal lubricating process would maintain a consistent, hlgh coating weight level of reacted lube, avoid the introduction into the lubricating solution of byproducts that interfere with the desired reaction between constituents of the phosphate coating and constituents of the lubricating solution, and remove little or none of the phosphate coating that was on the metal when it entered the lubricating solution. No actual lubricating solution known can accomplish such ideal lubrication, kut preferable practical baths tend toward maximizing the ratio o~ reacted lube coating weight to conversion coating loss, with consideration toward opti~izing the ratio o~ reacted lube coating weight to unreacted lube coating weight.
Th~ most preferred embodiments of the process according to the invent;on utilize complexing agents and OSOC component in lubricating baths from near the beginning of use of a freshly made bath. In such embodiments, satisfactory operating conditions C21n generally be attained by selecting an upper bound on the concentration of "titratable m~tal~", as defined exactly below, and by adding complexing agent a~ter each ~easure~ent of titratable metal~ concentration tha~ is ~igh~r than the selected upper limit. The amount of complexing agent should be at least sufficient to bring the concentration of titratable metals under a selected upper limit value. The best upper limit value ~ay be determined most precisely from experience with each particular lubricating solution composition and type of base metal and phosphate coating lubricated, but in g~neral an upper limit of 0.~5 % by weight or less is preferred.

Most preferably, lubricating processes and solutions according to this invention should be controlled, from the beginning of use of a freshly made ~olution, so that the concentration of titratable metals never rises above its selected upper limit during the en ire period of use of a lubricating solution according to the invention.
Therefore, it is more preferable to add sufficient complexing agent, after each measurement of titratable metals, to bring the titratable metals concentration below two-thirds or less of its upper limit value immediately after addi~ion, and to measure the titratable metals concentration suf~iciently often so as to assure that the concentration never rises above the selected upper limit.
It is generally most preferable in such situations to add sufficient complexing agent to bring the titratable metals concentration below 0.01 % by weight after each measurement of a higher value for this concentration.
Whil~ the method described above of utilizing lubri-catin~ solutions that contain complexing agent and OSOC
components from at or near the beginning of their use is most preferred, the process according to this invention may also be usefully embodied by starting with a conventional lubricating solution, containing :little or no complexing agent, that has already been useld for phosphating to a sufficient extent to accumulate a concentration of titratable metals greater than the desired upper limit for processes according to this invention. In such an embodi~ent, it has been found that it may be disadvantage-ou~ to add the very large amount of complexing agent that might be needed to reduce the concentration of titratable metals to very near zero. Such a large amount of complexing agent may cause excessive conversion coatinq losses during lubricating. Instead, when a process according to this invention is being initiated with a lubricating solution already containing more than 0.05 % by weight of titratable metals, it i8 preferabl~ to add initially an amount o~ complexing agent that will produce a concentratlon of complexing agent in the solution that is within the range of 5 to 9 times the measured titratable metals concentration, with a ratio of 6.5 - 7.5 most preferred. At the same ti~e, ~ufficient OSOC component to maintain the preferred r`atio between the compl~xing agent and the OSOC component as stated above is also preferably added. The concentration of titratable metals remaining after this initial addition of complexing agent is then preferably measured; it will usually be b2tween 0.01 an~
0.05. After the initial addition of complexing agent, the process according to the invention is preferably continued in the same general manner as described above for embodiments in which complexing agent is added to the lubricating solution from the beginning of its use, except that the additions of complexing agent should be limited so that they do not reduce the concentration o~ titratable metals below three-quar~ers of their concen'cration after the initial addition of complexing agent.
In all processes accvrding to this invention, the OSOC
componsnt preferably should be added to the lubricating solution at the same time as the complexing agent, in sufficient amount to ~aintain the ratio between these two components wi~hin the already stated preferred range~
After so~ operating ¢xperience with the same or a similar type of ~etal substrate and phosphating conditions, it is readily feasible to operate the proce~s according to this invention success~ully without explicitly measurins the concentrations o~ dissolved titratable metals, simply by adding appropriate amounts of complexing agent and OSOC
componen~s to a lubricating solu~ion at in~ervals as the solution is used ~or lubricating.
The temp2rature of the lubricating solution and the ti~e of contact between the lubricating solution and the phosphated surface in any process according to this inven-tion are generally within the range oP such conditions asused in the art for reactive lubricationO For example, the temperature is usually preferably between 70 and 90~ C and :29~7~

the time of contact betwean 1 and 10 minutes.
The practice of the invention ~ay be further appreci-ated with the help of the following non-limiting operating examples.
Examples General Condit1ons ~or All_the Examples and Comparative Examples The temperature of the lubricating solutions was maintained at 79D C~ and phosphated metal specimens were contacted with the solution for 5 minutes, then dried for 15 minutes in an oven maintained at 121- C. The test specimens were Type 1010 cold rolled steel that had been phosphated by use of Bcnderite~ 181x, a commerci~l zinc phosphat.ing solution available from the Parker+Amchem Division of Henkel Corpor-ation, ~adison Heights, Michigan, in a ~olution maintained with a total acid number of 30 points. (Points in this instance are definPd as the number of milliliters of Q.1 N
NaOH solution re~uired to titrate a 5 ml sample of the phosphating solution to a phenolphthalein end point.) The avarage phosphate coating weight was 12.8 grams per square meter of surface (g/m2) for all the panels except those used în Experiment 5, for which the avlerage coating weight was 21 g/m2.
The free acid or ~ree alkali.nity and the titratable metals content of the lubricating solutions were measured according to ~h~ following procedures:
Free ~Lcid Pour 200 ~1 of a solution o~ 0.2 % by weight phenolphthalein in isopropyl alcoh~l into a ~00 ml beaker, then add a 10 ~1 sample of hot lubri-cating solution, ~easured with a co~ical graduate or a pipet. Heat the mixture in the beaker to boili~g, a~d boil for at least one minute~ Re-move from heat and titrate i~mediately, while the solution is s~ill hot, with 0.1 N NaOH solution if the ~olution is clear rather than pink, to the development of a permanent, faint pink. The ml of titrating solution required is the number of "points" of ~ree acid. If the ~olution is already pink a~ter boiling, titrate with 0.1 N
sulfuric acid instead to the permanent disappear-ance o~ the pink color. The number oP ~1 of acid is then the Ipoints of free alkalinity.
Titratable ~etals Place 20 grams or 20 ml of a homogenized lubricating solution sample into a 150-ml beaker, dilut~ wit~ 20 ~1 deioniæed water and add 1 ml of concentrated HCl. Heat on a hot plate to separ-at~ the fatty acid layer. Cool and filter through Whatman #541 filter paper into a 200 ml tall form beaker. Cool, dilute to 100 ml in a glass-stoppered flask. Transfer a 25-ml aliquot fro~ the glass-stoppered flask to a 200-ml tall ~orm beaker. Add 1 drop of methyl red indicator solution and neutralize with NH40H. Add 5 ~1 of - "Reagent Solution ~5", a 2 % by weight solution of hydroxylamine hydrochloride in water, and mix.
Add 2 ml o~ "Reagent Solution 87", a solution of 6.7 % by weiqht of ammonium:chloride, 57 % by weight concentrated aqueous a~monium hydroxide, and 0O5 ~ by weight magnesiu~ EDTA in water, and mix. Add 2 ml o~ 10 ~ Sodium ~yanide solution and mix. ~dd about one-eighth teaspoon of "Indi-cator 24", a solid mixture of 99.6 ~ by weight dPxtrose, 0.2 ~ by weight magnesiu~ EDTA, and 0.2 % by weight Eriochrome black, and titrate with "Titra~ing Solution 86", a 0.4 ~ by weight solu-tion of sodium EDTA in water, to a color change fro~ a wine red to a light blue, r~taining the sample for the zinc titration.
% (Ca + M~L - 0D4 fml_o~ "Tit~ating Solution 86 original ~ample siz~
N.B.: If a ~ample contain~ iron and/or alum-inum, a sha~p~r end point is obtained if ~0 g .. . . ~ :

.,~
ml of 30 % by weight triethanolamine in water i~ added to the sample prior to the addition of "Reagent Solution 87" in the calcium + magnesium deter~ination.
Reset the buret to zero and add a few drops of "Reagent Solution 88", a solution of 18 % by weight for~aldehyde and 2 ~ by weight methanol in water, to the sample ~rom the calcium + magnesium titration and titrate with Ti rating Solution 86 ~o a new red-to-blue end pointO Add another drop-of "Reagent Solution 88" and titrate with "Ti-trating Solution 86" again. Repeat until 1 drop of "Reagent Solution 88" requires no additional titra~ion. The additional oonsumption of "Ti-tratin~ Solutio~ 86" represents zinc ~et free from the cyanide complex.
z _ 0.065~(ml added "~itrating Solution 86"~
n ~ original sa~ple size Pipet a 0.5-ml aliquot o~ the original fil-tered sample from its oriyinally prepared 100-~1 glass stoppered ~lask into a 100-~1 glass stop-pered, graduated cylinder. Add 5 ml of "Reagent Solution 65", 10 ml o~ "Indicator 19", a solution of 1.5 % by weight of ammonium citrate and 0.05 % by weight of orthophenanthroline ~onohydrate in water, and 1.0 ml of "Reagent Solution 90", a solution of 5 ~ by weight of l,10-phenanthroline in isopropyl alcohol. Dilute to 100 ~1. Mix by upending twice and allow to stand ~or 1 hour.
3Q T~en d~termine the percent transmittanc~ at a wavelength of 510-525 nm. Read ~g Fe from a standard curveO The standard curve is obtained by the ~ollowing procedure: To a series o~
lOO~ml glas~-stoppered cylinders, add 0, 0.5, 1.0, 1.5, and 2.0 ~1 of "Standard Solution 91", a solution of 0.03 ~ by weight f~rrous ~ulfate and 2 % by weight ~ulfuric acid in water. ~hese .. . .
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amounts correspond to o, 0.5, o.l, 0.15, and 0.2 ~g Fe. Then ad~ 5 ml o I'Reagent Solution 65"
and 10 ml of "Indicator 19" to each cylinder.
Dilute to lOo ml with deionized water and mix by upending twice. Allow to ~tand at least 10 minutes, then determine the percent transmittance of each standard, using a deionized water blank, at a wavelength of 510-525 n~ (510 nm is pre-~erred). Prepaxe a standard curve by plotting mg Fe against percent transmittance using semiloga~
rithmic paper, with transmittance on th~ l~ga-rithmic scale and mg Fe on the arithmetic scale.
% Fe _ OOl(m~ Fe from_standard curve~
~ milliliters of original sample The "titratable metals" concentration of the solution is then defined as: % Zn + ~1.64)(% Ca + Mg) + (1.16)(~ Fe).
The viscosity of the lubricating solutions was mea~ured with a #2 Zahn Cup.
Coating weights and other related charaoteristics of the samples are de~ined and/or were determined as follows:
Wl = Weight ~in gram ) o~ panel and phosphate coating.
W2 - Weight (in grams) of panel, phosphate coating, and lube coating after axposure to lubricating solution.
~3 = Weight (in grams) of panel after exposure to phosphating and lubricating solutions, followed by water strip.
Water strip: Immerse pan~l in boiling deionized water, in sufficient volume to provide at least abou 4.3 ml o~ water per ~quare centimeter o~ panel surface, ~or three minute~ Remove panel and rinse by immersion in a similar volume of boiling deioniz~d water ~or three minutes. Remove rinsed panel and dry in oven, cool to ambient temperature, and weigh.

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W4 = Weight (in grams) of panel after exposure to phosphating and lubricating solutions, followed by water strip as above a~d solvent strip.
Solvent 5trip: Place panel in extraction portion of a Soxhlet or similar extractor that accumulates freshly distilled solvent in a container to a specified level, then drains the accumulated solvent, and repeats the cycle. Make sure all panels loaded are lo completely covered when the container is filled to just ~elow the level that produces drainage. Extract for at least 30 minutes with condensat~ from a vigorously refluxing ~nixture of 55 % by weight isopropyl alcohol, 32 ~ by weight n-heptane, and the balance 2-ethoxyethanol. Remove panel, d.ry in oven, cool to ambient temperature, and weigh.
W5 = Weight (in grams) of panel after exposure to phosphating and lubricating solutions, followed by wat~r strip and solvent strip as specified above and then by chromic acid strip.
Chromic~Acid Strip: Prepare solution by dissolving 800 g o~ CrO3 in sufficient water to make 4 liters. 'Heat solution to 82 C
and maintain at that temperature with stirring and thermos~atic control. Immerse panel for 5 ~inutes. Re~ove panel fro~ hot solution, rinse quickly in cold water, dry with clean compressed air, and weigh.
Surface Area is ~easured in square ~eter~.
A~ Conversion coating loss = sL~lac W~
B) Nonreacted lube = (W~f~ ~3~ -C) Reacted lube = Surface Area D) Residual Conversion ooating = (W4 _ W5~
Sur~ace Area . :"

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E) Total lube = Nonreacted lube ~ Reacted lube.
Specific Expe~i~ents An initial lubricating solution as freshly mad~ up consisted of 3.6 % by weight in water of a sodium soap mixture that was made by neutralizing with sodium hydroxide a technical fatty acid mixture that is at least 95 %
stearic acid. Solution No. 1 was this freshly made solution, while solutions Nos. 2 - 5 had been aged through actual use to lubricate phosphated surfaces. Characteris-tics of the solutions at the start are given in Ta~
The following experiments were then per~ormed:
Experiment #l Coated panels in solutions 1 - 4.
Measured coating weights.
Experiment #2 Added 1.5 g/L EDTA tetrasodium salt to Solution 2.
Added ~ g/L EDTA tetrasodium salt to Solution 3.
Added 5 . 5 g/L EDTA tetrasodium salt to Solution 4. Coated panels in solution~ 2 - 4 as modi~ied by these first additions.
Measured coating weights.
Experiment #3 Added 0.5 g/L of PEG 4000 to Solution 2.
Added 1.25 g/~ of PEG ~000 to Solution 3.
Added 1.8 g/~ o~ PEG 4000 to Solution 4.
Coated panel~ in solutions 2 - 4 ~s modified by these second additions .
MeasurQd coating weight~.
Experiment~~
Added various levels of EDT~ tetrasodium salt (complexing salt) an~ PEG 4000 ~o solution 5, coating panels after each addition.
1st Addition: 5 ~/L complexing salt, 2.5 g/L PEG.
2nd Addition: 5 g/L co~plexing salt, No PEG
3rd Addition: 5 g/L complexing salt, 2.5 g~L PEG
Total~ Added: 15 g/L complexing salt, 5 ~/L PEG.

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Table 1 Characteristics of Experimental_~ubricatingLSolutions Solu- Char cteristic _ Value:
tion For Exper- For Exper- For Exper-S No. iment # 1 iment # 2 iment # 3 (No Addi- (EDTA (EDTA~PEG
tive~ ~dditivç~ Additive~
1 Soap Content, g/L 32 Free Acid Points 0 Viscosity, Sec.14.5 Total Titratable Metals, weight % o 2 Soap Content, g/L 34 34 34 Free Acid Points 0.4 0.4 0.4 Viscosity, Sec.14.5 16 15 Total Titrata~le Metals, weight % 0.02 o o 3 Soap Content, gjL 30 30 30 Free Acid Points 0.3 0.3 0.3 Viscosity, Sec.14.5 15.5 14 Total Titratable Metals, weight % 0.06 o o 4 Soap Cont~nt~ g/L 32 3~ 32 ~.
~ree Acid Point~ 0.4 0.4 0.4 Visco~ity, Sec.14 16 14.5 Total ~tratable Metals, weight % 0.08 0 o Experiment ~ 4 ~t After After ~fter ~0 Start ~irst Second Third Addi- Addi- Addi-~ion tion tion (EDTA (EDTA (EDTA
:~L Only~L PEG
Soap Content, g/L 45 45 45 45 Free Acid Points 0.2 0.2 0.2 0.3 To~al Titra~able ~etals, weight % 0.18 0.103 0.035 o 2~7 I

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The characteri tics of the solution~ after each of the additions in th~se expeximents are also shown in Table 1.
The results of the coating weight and related measurements ~rom these experi~ents are shown in Table 2.
Experiment l, a comparative example, shows that an increase in divalent metal cations decreases conYersion coating loss and lube reactivity. The conversion coating loss goes fro~ 2.6 down to 1.7 g/m2 wh~n the divalent metal increases to 0.08%. Along with this the reacted lube decreases from 10.5 down to 3.9 g/m2.
Experiment 2, also a comparative example, shows the effect the addition of EDTA tetrasodium salt has on the coating process. At all three level~ of divalent metals, there is an increase in reacted lubricant. The bigges~
change is se~n in solution #4 which contains the highest level of metal ions. The amount of nonreacted lube greatly increases, due to the increase in solution viscosity from 14 to 16 seconds.
Experiment 3, according to the pre~ent invention, shows how the polyethylene glycol not only returns the olution to a lower viscosity but also improves the ratio of reacted lube to nonreacted lube and of reacted lube to conversion coating loss. The nonreacted lube weights came down while the ~uch more desirab.le reacted lube w~ights increased, even though the conversion coating loss stayed about the sa~e.
~xperiment 4, also according to the present invention, shows how the proper initial addition of ED~A tetrasodium salt and polyethylene ~lycol should preferably be based on the initial di~alent metal ion concentration to optimize coating weights. The addition o~ large amounts of EDTA
te~rasodiu~ salt, a~ exemplified by the third addition in this experiment, will increase converæion coating loss but will not i~prove lube coating wei~ht very ~uch, once substantially all o~ the divalent metal cations present have been complexed. The seco~d addition of complexing agent thu~ leave~ this particul~r solution with more 2 ~
desirabl~ lubricating properties overall than are produced by the third addition, even though the concentration of titratable metals remains well above 0.01 % by weight after the second addition but is below that after the third addition. Thus this third addition of EDTA brings the solution outside the most preferred range of complexing agent concentrations, even though still within the scope of the invention.
Although it is preferable, as already stated, to keep the concentration of titratable divalent metal ions in the solutions according to this invention below 0.05 weight %, the inv~ntion can be useful in solutions containing up to 0.2 weight % of such titratable divalent metal ionsO

: What i8 claimed is:

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Claims

1. A liquid composition of matter, consisting essentially of: (A) water; (B) a reactive metallic soap component: (C) a complexing agent component; (D) an OSOC component consisting of organic molecules having at least one hydroxyl or ether oxygen atom for each eight carbon atoms and stable in solution or dispersion in the composition; and (E) up to about 0.2 % by weight titratable metals.

2. A composition according to claim 1, wherein the OSOC
component is selected from molecules containing at least one hydroxyl or ether oxygen atom for every two carbon atoms.

3. A composition according to claim 2, wherein the complexing agent is selected from the group consisting of EDTA and its salts, NTA and its salts, NEDTA and its salts, diethylene triamine pentaacetic acid and its salts, diethanol glycine, and the material having CAS Registry No. 68611-02-9*.

4. A composition according to claim 1, wherein the complexing agent is selected from the group consisting of EDTA and its salts, NTA and its salts, NEDTA and its salts, diethylene triamine pentaaretic acid and its salts, diethanol glycine, and the material having CAS Registry No. 68611-02-9*.

5. A composition according to claim 4, wherein the OSOC
component consists of molecules selected from the group consisting of alkylene glycols, poly(alkylene glycols), glycol ethers, ethoxylated alcohols, polymers and copolymers of ethylene oxide and propylene oxide, and glycerin.

6. A composition according to claim 1, wherein the OSOC
component consists of molecules selected from the group consisting of alkylene glycols, poly(alkylene glycols), glycol ethers, ethoxylated alcohols, polymers and copolymers of ethylene oxide and propylene oxide, and glycerin.

7. A composition according to claim 6, wherein (I) the concentration of reactive soap is within the range of about 5 to about 150 g/L, (II) the concentration of complexing agent component is not greater than an upper bound that is the greater of (A) about 0.1 g/L
and (B) the minimum amount necessary to reduce the concentration of titratable metals in the composition below 0.05 % by weight, and (III) the OSOC component consists essentially of PEG 4000 and its concentration in the composition is such as to produce a ratio between the concentration of the complexing agent component and the concentration of the OSOC component within the range between about 1 and about 5.

8. A composition according to claim 4, wherein (I) the concentration of reactive soap is within the range of about 5 to about 150 q/L, (II) the concentration of complexing agent component i's not greater than an upper bound that is the greater of (A) about 0.1 g/L
and (B) the minimum amount necessary to reduce the concentration of titratable metals in the composition below 0. 05 % by weight, and (XII) the OSOC composition consists essentially of PEG 4000 and its concentration in the composition is such as to produce a ratio between the concentration of the complexing agent component and the concentration of the OSOC component within the range between about 1 and about 5.

9. A composition according to claim 8, wherein the complexing agent component is selected from EDTA and its salts.

10. A composition according to claim 7, wherein the complexing agent component is selected from EDTA and its salts.

11. In a process for phosphating a metal surface and subsequently contacting the phosphate layer formed thereby with an aqueous lubricating solution of a reactive lubricant component and a component of complexing agent for any divalent metal cations in said phosphate layer, under conditions so as to form a reacted lube layer on said metal surface, the improvement wherein said aqueous lubricating solution also contains a OSOC component consisting of organic molecules having at least one hydroxyl or ether oxygen atom for each eight carbon atoms.

12. A process according to claim 11, wherein the OSOC
component of the lubricating solution is selected from molecules containing at least one hydroxyl or ether oxygen atom for every two carbon atoms.

13. A process according to claim 12, wherein the complexing agent in the lubricating solution is selected from the group consisting of EDTA and its salts, NTA and its salts, NEDTA and its salts, diethylene triamine pentaacetic acid and its salts, and diethanol glycine.

14. A process according to claim 11, wherein the OSOC
component of the lubricating solution consists of molecules selected from the group consisting of alkylene glycols, poly(alkylene glycols), glycol ethers, ethoxylated alcohols, polymers and copolymers of ethylene oxide and propylene oxide, and glycerin.

15. A process according to claim 14, wherein, in the lubricating solution, (I) the concentration of reactive soap is within the range of about 5 to about 150 g/L, (II) the concentration of complexing agent component is not greater than an upper bound that is the greater of (A) about 0.1 g/L and (B) the minimum amount necessary to reduce the concentration of titratable metals in the composition below 0.05 % by weight, and (III) the OSOC component consists essentially of PEG 4000 and its concentration in the composition is such as to produce a ratio between the concentration of the complexing agent component and the concentration of the OSOC component within the range between about 1 and about 5.

16. A process according to claim 15, wherein the concentration of titratable metals in the lubricating solution is maintained below a preselected upper limit value during use of the solution for lubricating, by addition of complexing agent to the solution.

17. A process according to claim 14, wherein the concentration of titratable metals in the lubricating solution is maintained below a preselected upper limit value during use of the solution for lubricating, by addition of complexing agent to the solution.

18. A process according to claim 13, wherein the concentration of titratable metals in the lubricating solution is maintained below a preselected upper limit value during use of the solution for lubricating, by addition of complexing agent to the solution.

19. A process according to claim 11, wherein the concentration of titratable metals in the lubricating solution is maintained below a preselected upper limit value during use of the solution for lubricating, by addition of complexing agent to the solution.

20. A process according to claim 11, wherein the lubricating solution before beginning the process contains more than 0.05 % by weight of titratable metals, the concentration of titratable metals in the lubricating solution is reduced at the beginning of the process by adding to the lubricating solution an amount of complexing agent sufficient to provide a concentration of complexing agent in the solution that is within the range of about 5 to about 9 times the concentration of titratable metals that was present in the lubricating solution before beginning the process, and the concentration of titratable metals in the solution is maintained, during subsequent use of the solution for lubricating, within a range having an upper bound of about 0.05 % by weight and a lower bound of about two-thirds of the concentration of titratable metals after the first addition of complexing agent at the beginning of the process, by addition of more complexing agent to the solution as the solution is used.