CA2220419A1 - Composition and process for treating metal - Google Patents

Abstract

Heating an aqueous mixture of a fluoroacid such as H2TiF6 and an oxide, hydroxide, and/or carbonate such as silica produces a clear mixture with long term stability against settling of any solid phase, even when the oxide, hydroxide, or carbonate phase before heating was a dispersed solid with sufficiently large particles to scatter light and make the mixture before heating cloudy. The clear mixture produced by heating can either be mixed with water soluble and/or water dispersible polymers, for example with dispersed polymers of the diglycidyl ether of bisphenol-A or an acrylic acid polymer, or with soluble hexavalent and/or trivalent chromium, to produce a composition that improves the corrosion resistance of metals treated with the composition, especially after subsequent painting. Another composition that improves the corrosion resistance of metals after contact with them is an aqueous solution of a mixture of: (A') a water soluble or dispersible polymer having at least one -OH group per polymer molecule selected from the group consisting of polyvinyl alcohol, polyethylene glycol, modified starch, and mixtures thereof, and (B') polymers and copolymers of acrylic and methacrylic acid and their salts.

Description

W 096/35745 PCTrUS95/05225 COMPOSITION AND PROCESS FOR TREATING METAL

Field of the Invention This invention relates to plvcessGs of treating metal s~ s with aqueous acid-ic compositions to increase the re~i.cf~nre to corrosion of the treated metal sllrf~ce7 ei-10 ther as thus treated or after subsequent overcoating with some convçl-lion~l organic based plvLG~;LivG layer. A major object of the invention is to provide a storage stable, preferably single package, tre~tm~-nt that can be ~..hs~ ti~lly free from hexavalent Cl~l'OllliUlll but can protect metals subst~nti~lly as well as the hexavalent Ch~'U111iU111 CO;~ g L~G~IIIIP~ ; of the prior art, or can illlprovG the stability of tre~tm~-nt solu-15 tions that do contain hexavalent cl~.~uliu.lThis invention also relates to reaction of fluol~ t~llic acids with other metal or m~t~ icl col~l;1ill;l-g m~tt~.ri~l~ to produce compositions or int~rmprli~tes for compositions useful for such tre~tment~

Statement of Related Art 2 0 A very wide variety of m~t~ri~lc have been taught in the prior art for the gen-eral purposes of the present invention, but most of them contain hexavalent Chlullliu or other inorganic oxicli7ing agents which are envil~l....ent~lly undesirable. Also, many of the prior art LIG;1ll11~.1l compositions include colll~ Gllt~ that are chPlni~lly or physically lln~t~hle when mixed, so that single package concel~dLGs for such tre~tm~nt culL~o~iLions are not practical.
DESCRIPTION OF THE INVENTION
Except in the claims and the opel,.~ eY~mple~, or where otherwise expressly in-lir.~te-l all nnm~.rir.~l qll~ntiti-o.c in this description in-lie~ting ~11OU11L:j of m~t~.ri~l or conditions of reaction and/or use are to be nnrlP.rstood as m~-tlifi~o.d by the word ~ 3 0 "about" in des~rihing the broadest scope of the invention. Practice within the numeri-cal limits stated is generally ~lcre~lGd. Also, unless expressly stated to the collLlaL~;
percent, "parts of", and ratio values are by weight; the term "polymer" inr~ s oligomer; the des~ription of a group or class of m~teri~l.c as suitable or ~erGl.cd for W 096/35745 PcT/u'75-~5~25 a given ~u.~ose in conn~ction witn the invention implies that ~ LulcS of any two or more of the Illr..llh,.~.~ of the group or class are equally suitable or ~lefc~l~,d; descrip-tion of conctitllents in ch~mi~l terms refers to the cnn~ te~ at the time of ~d~lition to any cl mhin~tion spec-ified in the description, and does not n~cecc~rily preclude 5 c.h~mic~l interactions among the conctituentc of a llli~lulc once mixed; specific~tion of m~feri~le in ionic form implies t'ne presence of sllfficient cuunlclions to produce electric~l nelltr~lity for the ~;olll~o:jiLion as a whole (any co~ r.. ;nnc thus implicitly specified should preferably be selecte.-l from among other co~ ; explicitly spec-ified in ionic form, to the extent possible; otherwise such countclions may be freely 10 sel~cte-l, except for avoiding cuu-.l~..;c-l-.c that act adversely to the stated objects of the invention); and the term "mole" and its variations may be applied to elem-o.nt~l, ionic, and any other ch~mic~l species defined by nulllbel and t,vpe of atoms present, as well as to compounds with well defined molecules.
Summar,v of the Invention It has been found that aqueous colll~osiLions cn---l--;c;--~ (A) a colll~ollcllt of dissolved fluoroacids of one or more metals and m.o.t~lk)i~ mr.ntc selected from the group of ~olemPntC concicting of ti~ i.. , zi.colliu~ll, h~fninm, boron, ~l~.. i.. , sil-icon, ~,r~ ll;lllll, and tin and, (B) a colll~on~,..t of one or more of (i) dissolved or dis-persed finely divided forms of metals and mr.t~llc)itl elem~ntc selocte-A from the group of el~m~.nts concicting of lil~,.i.. , ;~;OlliUl~l~ h~fnillm, boron, ~ ;n~ silicon, ger-m~nillm, and tin and (ii) the oxides, hydroxides, and carbonates of such metals and metalloid elem~ntc can be caused to r.hP.mi~lly interact in such a manner as to pro-duce a co-ll~osiLion useful for novel metal L--,~lll---i-l.~ Lf cu-ll~un~"-l (B) is present in ~licpercion rather than solution, as is generally ~lGrcllGd, the initial cc,lll~osiLion nor-mally will not be optically L-~ls~d.cnt, because of the sC~ttering of visible light, in a thie~nto.cc of 1 c~ r~e~ ("cm"), and the oc~;ullcnce of the desired çh~.mi~ l interac-tion can be ~lrlr----;-~d by the ~ rifi~tic)n of the culll~o~ilion~ If CO111~I1G1IL~ (A) and (B) as defined above are both present in the precursor aqueous colllpo~iLion in suffi-ciently high con~-e~ dLions, adequate ch~mi~l interaction b~,lwccn them may occur 3 0 at normal ~mhient ~r~ el~ s (i.e., 20 - 25 ~ C) within a pr~çti~l reaction time of 24 hours or less, particularly if CU1111)O11G11L (B) is dissolved or ~ e~1 in very finely divided form. l!~erh~ni~ git~tion may be useful in spee~ling the desired çhemit ~l W 096/3574~ PCTrUS95105225 intPr~rtion and if so is preferably used. ~e~ting, even to relatively low lcln~cl~lulcs such as 30~ C, is often useful in spee~lin~ the desired rh--mir.~ a~LiOn, and if so is also ~.crcllGd. The desired ch~.mir~l intP.r~cction between components (A) and (B) of the mixed composition ~ es or at least m~rko~lly reduces any tendency toward settling of a rlicppr~ce~ phase that might otherwise occur upon long term storage of the initial llfi~Llulc of col,lyollclll~ (A) and (B) as defined above.
The cw,,L)osilions rçs--lting from çhPmir~l interaction as described above may then be utilized as metal treating cc,lll~o~il;onc, optionally after being comhinP-l with a colll~oll~ (C) that is either (i) a water soluble or tlicpercihlP polymer and/or copol-ymer, preferably sçlect~ from the group concictin~ of (i.l) polymers and copolymers of one or more x-(N-R~-N-R2-~lll;,,~.,,-~lhyl)-4-llyL~,~y-~Ly,c.les, where x = 2, 4, S, or 6, Rl lcpl~cscllts an aLkyl group CO~ ;"i,~g from 1 to 4 carbon atoms, preferably a methyl group, and R2 lc~l-,ScllL~ a :j~lbc~ group conrulll~illg to the general formula H(CHOH)nCH2-, where n is an integer from 1 to 7, preferably from 3 to 5, (i.2) epoxy resins, particularly polymers of the diglycidylether of bicphPn-)l-A, optionally capped on the ends with non-poly.ll~ hhP. groups and/or having some of the epoxy groupshydrolyzed to hydlo~yl groups, and (i.3) polymers and copolymers of acrylic and mPth~r.rylic acids and their salts; or (ii) a composition coll~;1;llil~g hexavalent chrom-ium, and, optionally but preferably, trivalent chlullliull~.
Optionally, another culll~ollcl,L (D) made up of water soluble oxides, carbon-ates, or hydroxides of at least one of Ti, Zr, Hf, B, Al, Si, Ge, and Sn may also be added before, after, or cimlllt~nPously with c-,lll~ollcnt (C) but after the interaction of coll~ollelll~ (A) and (B). For this y~u~ose~ "water soluble" means a solubility to at least 1 % in water at normal ~ hiel)~ Ltlllpe.dlun;, and "water insoluble" means less soluble than this.
The rçslllting co",~osiLions are suitable for treating metal surf~rçs to achieveçxrçllr.nt r~cict~nre to corrosion, particularly after subsequent convt;llLional coating with an organic binder co~ in~ protective coating. The compositions are particu-larly useful on iron and steel, galvanized iron and steel, zinc and those of its alloys 3 0 that contain at least 50 atomic percent zinc, and, most preferably, ~ . " and its alloys that contain at least 50 atomic percent ~l.~...;.,..,.~ The treating may consist ei-ther of coating the metal with a liquid film of the co"l~o~iLion and then drying this W 096135745 PCTrUS9~105225 liquid film in place on the surf~e of the metal~ or simply cont~ctin~ the metal with the co.l-po~iLion for a sllmrirnt time to produce an h~ vcll~cllt in the .~ rc of the surface to corrosion, and subsequently rinsing before drying. Such contact may be achieved by spraying, i,.",~ inn, and the like as known per se in the art. When 5 this latter method is used, it is optional, and often advantageous, to contact the metal surface with an aqueous cvlll~osilion cl mrricing polymers and copolymers of one or more x-(N-RI-N-R2-~llinol..cll.yl)~-l.yd~y-styrenes, where x = 2, 4, 5, or 6, Rl rep-resents an alkyl group Co"l~i"il~ from 1 to 4 carbon atoms, preferably a methyl group, and R2 rt~.csents a .s~lhstitllent group COllrOlll~illg to the general formula H(CHOH)nCH2-, where n is an integer from 1 to 7, preferably from 3 to 5, after con-tacting the metal with a composition c~ g components (A) and (B) as ~ltoscrihed above, rtllluvillg the metal from contact with this co..lpo~i~ion co"l~ i"~ co (A) and (B) as described above, and rinsing with water, but before drying.
The invention also provides a process for cLrc.; ively coating the above-stated mrt~llic surfaces in the absence of an i"~ tP. rinsing step. The process c~ mrrices the steps of (i) cle~ning the metal surf~e to be coated, (ii) rinsing the clo~nto~l metal surface with water so as to remove any excess clr~ning solution, (iii) cont~rtinp the mrt~llir surf~e with the above-rlescrihed coating cc,lll~o~iLion, and (iv) drying the coated mr~t~llic surf~e.
2 0 There is also another embodiment of the present invention which provides a composition and process for coating ~.. r~r~c of ~l.. i.. and alloys thereof, whclci the cunlposi~ion cnmprices, preferably consists essenti~lly of, or more preferably consists of, water and a mixture of: (A') a water soluble or ~licprrcihle polymer having at least one alcohol functionality 5rlectr-~l from the group co~cictinp of polyvinyl 25 ~lrohnl polyethylene glycol, mn-lifi~l starch, and ~ixl~.es thereof and (B') polymers and copolymers of acrylic and mrth~crylic acid and their salts, and, optionally, one or more of the following: a colllyol~ (c~) sel~octrA from the group col~ g of the same fluorom~t~llic ~ids, with the same p.crclences, as recited for coll.pol,ent (A) herein; a co ll~oncn~ (D') of mpt~llic and/or metalloid elements and their oxides, 3 0 hydroxides, and/or C~~ Lcs, with the same ~lcrclcnccs~ as recited for col..~o,.~ L (B) herein; and a coll.~ncnt (E') selected from the group co~ li"~ of water soluble oxides, carbonates, or hydroxides of at least one of Ti, Zr, Hf, B, Al, Si, Ge, and Sn W 096/35745 PCTrUS95/05225 as recited for co~ ullcnt (D) herein.
It should be Im-lrr.ctood that the ~1~serirtir,nc of compositions above do not pre-clude the po.c.cihility of ~ c.-;rilocl chrrnir~ .deLions among the co.,l~ollcllL~ listed, but instead describes the cclll~onG.lts of a composition according to the invention in the form in which they are generally used as ingredients to prepare such a composi-tion. In fact, a ch~ornir~l inLeld~;Lion, most probably to produce oxyfluro complexes of the metal or metalloid cl- . l lr~ or their co.ll~ou.lds heated in contact with fluorr,m~.t~llir acids, is believed to occur, but the invention is not limited by any such theory.
Descli~lion of P~G~Il~,d Embo~1i",~.l"x To the extent that their water solubility is sllfficient the fluoroacid cc~ ol~ent (A) to be caused to interact in a mixture with one or more metals and/or mr.t~llc)i-l ele-ments and/or oxides, hydroxides, and/or carbonates thereof in a process according to one embodiment of the invention may be freely selectçd from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H3AIF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and ll~i~lulGS thereof.
H2TiF6, H2ZrF6, H2HflF6, H2SiF6, HBF4, and ll~UL~ ,S thereof are plcr~lcd; H2TiF6, H2ZrF6, H2SiF6 and l~Lulcs thereof are more ~lGr~ d; and H2TiF6 is most ~lcÇcllcd.
The cr,nr.r.ntr~tion of fluoroacid CU111~O1IGI1l at the time of illlcld;Lion is preferably be-tween O.Ol and 7 moles per liter (hereinafter "M"), more preferably bGl~ 0.1 and6M.
The culll~ollcllt (B) of mrt~llir. and/or m.o.t~llr,i~l elPmr.ntc and/or their oxides, hydroxides, and/or c~b~ a~cs is preferably sel~ctr.~l from the group cr~nci.cting of the oxides, hydroxides, and/or c~lJolldLcs of silicon, ~ ;' l.;..,l., and/or ~l."..i.,...,. and more preferably inr.llldt-s silica. Any form of this colll~ollent that is sllffiri~ontly finely di-2 5 vided to be readily ~ ed in water may be used in a process accor~illg to one em-bo~lim.o.nt of this invention, but for col.~ e-~ i of this colll~onclll that have low sol-ubility in water it is pl~cr~.~lcd that the conctitllr.nt be amol~hou~ rather than crystalline, because crystalline con.ctitllpnt.c can require a much longer pcriod of heating and/or a higher Ir...l~ .c of heating to produce a c~ osiLion that is no longer ~usc~Lible 3 0 to settling and optically Lld~ d cnl. SrlllltirJnc and/or sols such as silicic acid sols may be used, but it is highly preferable that they be ~ lly free from aLkali metal ions as rle.srribecl further bclow. However, it is gen~ lly most prcr~,.lcd to use W096t35745 PCTtUS95/05225 dispersions of silica made by pyrogenic ~locesses.
An equivalent of a m--t~llic or m.otAllni(l el~rn.o.nt or of its oxide, hydroxide, or carbonate is defined for the purposes of this tlesr-rirtion as the amount of the m~t~.riAl co~ i..g a total of Avogadro's Number (i.e., 6.02x1023) of atoms of metal andlor 5 metalloid ~lem~ntC from the group cnn~ tin~ of Ti, Zr, Hf, B, Al, Si, Ge, and Sn.
The ratio of moles of nuoluacid culll~ ellt (A) to total equivalents of Culll~ul~;llt (B) in an aqueous composition heated according to one embo-lim~nt of this invention preferably is from 1:1 to 50:1, more preferably from 1.5:1.0 to 20:1, or still more preferably from 1.5:1 to 5.0:1Ø If desired, a con~titnent of this component may be 10 treated on its surface with a silane coupling agent or the like which makes the surface oleophilic.
According to one embodiment of the invention, an aqueous liquid culll~?osiLion comrri~ing, preferably con~i~ting e~PntiAlly of, or more preferably consisting of, water and colll~ollellL~ (A) and (B) as ~1~5~-. ;l~d above, which colll~siLion scatters vis-15 ible light, is not optically ~rA~ in a thi~n~ of 1 cm, and/or undergoes visually~l~tectAble settling of a solid phase if ...~;..l~;..~.-l for at least 100 hours at a le111Pe1A-ture between its freezing point and 20~ C, is IllAilllA;n~3d at a lelll~ LulG of at least 21~ C, optionally with ~ Sr.hAnic~l Agit~tiQn~ for a sllfflri~ont time to produce a compo-sition that (i) does not suffer any visually detect~hle settling when stored for a period of 100, or more preferably 1000, hours and (ii) is optically IlAI~;PA~n~ in a thi~ n~
of 1 cm. Preferably, the tGlll~GlaLulG at which the initial m-ixture of colll~c~nents (A) and (B) is mAint~in~d is in the range from 25 to 100 ~ C, or more preferably within the range from 30 to 80 ~ C, and the time that the cornposition is II~A;~IIZ1;11I'd within the stated t~ G range is wit_in the range from 3 to 480, more ~ f~;lably from 5 to 90, or still more preferably from 10 to 30, .. i.. ~ s (hereinafter often abbreviated "min"). Shorter times and lower t~-..pf..,1l...c,s within these ranges are generally ade-quate for c(~ Lillg c~slllposiLions in which the component (B) is selected only from dissolved species and/or dispersed amorphous species without any surface Ll~t---- -~
to reduce their hydr~lJhilicity, while longer times and/or higher ~ dLulcS within 3 0 these ranges are likely to be needed if colllponellL (B) inrlndec ~li.c~r.~ed solid crystal-line m~t~.ri~l.c andlor solids with ~... rAces treated to reduce their hy~l~upl-ilicity. With suitable e~ ;p.. ~.. l for ~ the reaction mixture, even higher l~ A~ S than W 096135745 PCT~US9~/05225 100~ C can be used in çspe~ lly difficult cases.
Indepcnfl~ntly, it is ~l~r~ cd that the pH of the aqueous liquid composition combining Ccll~ ;>nellLs (A) and (B) as described above be kept in the range from 0 to 4, more preferably in the range from 0.0 to 2.0, or still more preferably in the range from 0.0 to 1.0 before beginning ",~ n~ e at a l~ l.. c of at least 21~ C as de-scribed above.
A co.llposiLion made as flescrihed imm~ t~ly above is suitable for use as a p~ute-;livc L e;~ .l for metals. In many cases, however, a better protective tre~tml-nt ccln~o~iLion may be obtained by mixing the product of interaction between colll~on-10 ents (A) and (B) as des~rihc-l above with a third component (C) as also noted above.
To make such compositions in.~ln~ling CU111~U11G11L (C), after ~ n~ e of a COlll~Si-tion co,~ g colllpollcllL~ (A) and (B) as described above at a tellll~cld~ c and for a time s-lfflci~nt to promote their interaction, the cc,ll.~osiLion is pl~r~.dbly brought if l~CPc~,y to a te~ cldlUlc below 30~ C and then mixed with a com~oll~,.lL consist-15 ing of at least one of (i) at least one water soluble or ~ r.~ihle polymer and/or co-polymer, preferably s~ cte(l from the group con~i~ting of (i.l) poly_ydroxyl alkyla-mino dclivdLivcs of poly{p-hydro~y~Lylclle} as described above and, in more detail, in U. S. Patent 4,963,596, the entire ~licclosllre of which, except to the extent cullLldly to any explicit ~ herein, is hereby i. cûl~uldlt;d herein by lcrcl~,~lcc, (i.2) epoxy 2 0 resins, particularly polymers of the diglycidylether of hi~ph~nnl-A, optionally capped on the ends with non-poly..l~ hle groups and/or having some of the epoxy groups hydrolyzed to hy~u~yl groups, and (i.3) polymers and copolymers of acrylic and m~th~rrylic acids and their salts; and (ii) a cu..l~osilion cu,.l;.;"i"g hexavalent chrom-ium, and, optionally but plcrclably, trivalent Cl~ullliulll as known per se in the art for treating metals, particularly ~hlminllm and its alloys, to retard corrosion thereon.
Suitable and ~lcfell~,d water soluble polymers and m~thn-l~ of ~lcpa hlg them are de-scribed in detail in U. S. Patent 4,963,596. E'lcf~ldbly, the ratio by weight of the sol-ids content of colll~ollent (C) to the total of active ingredients of co-ll~oncllL (A) as ~rriheA above is in the range from 0.1 to 3, more prcrcldbly from 0.2 to 2, or still 3 0 more ~lcf~,.dbly from 0.20 to 1.6.
A cc,l~l~osiLion p~cpdled by a process as described above cn~ s another embodiment of this invention. It is nnrm~lly preferred that colllyo~iLions according W 096/35745 PCTrUS95/05225 to the invention as defined above should be ~ s~ lly free from many ingredients used in cu~ osiLions for si-m- ilar purposes in the prior art. Speçifir~lly, it is often in-creasingly ~lerc~lcd in the order given, indepçn~lf.ntly for each preferably ",;,~
co...pollellt listed below, that these cc~ poc;l;on~, when directly c-nt~rte~l with metal in a process accol.ling to this invention, contain no more than 1.0, 0.35, O.lO, 0.08, 0.04, 0.02, 0.01, or 0.001 % of each of the following con.~l;lu~ hexavalent dl~u~ u~ll; ferricyanide; ferrocyanide; anions cu..l~ molybdenum or tungsten; ni-trates and other oxi-li7ing agents (the others being measured as their oxi~li7ing sto-i-~hiomPtri~. equivalent as nitrate); phosrhnrus and sulfur C4--l;~ anions that are not 10 nxitli7.ing agents; alkali metal and ammonium c~tion~; and organic compounds with two or more l-y~Lo~yl groups per mnlf cnle and a mol~c~ r weight of less than 300.
The prcfc,c,lce for minim~l amounts of alkali metal and ~mmnnillm cations applies only to cu~ osiLions used for ~loces~es according to the invention that include drying into place on the metal surface to be treated without rinsing after contact bc~ the 15 metal surface and the col.l~o~iLion cc,..l~ i..g at least cc...~ollents (A) and (B) as de-scribed above; when a col.lpo~iLion accoldil g to the invention is cont~c~ with a metal surface and the metal surface is subsequently rinsed with water before being dried, any alkali metal and ~mmonillm ions present are usually removed by the rinsing to a sllfficif nt degree to avoid any s~ l;on of the protective value of 20 subsequently applied organic binder c~ p~ute~;Livc co~ting~ Also, the prefer-ence for ...il.;...;,;-l;on of the amount of hexavalent C~ullliulll present is due to the polluting effect of hexavalent ~ u~liu---, and where there is an absence of legal c~ against pollution and/or snffiri~ntly econ~lmic~l means of disposing of the hexavalent d~lvll iu~- without e~lviiù~....f ..l;.l damage exist, this ~cÇt ~,nce does not 25 apply. In fact, in one speci~li7~l embodiment of the invention, as already noted above, hexavalent Chlullliulll may advantageously be incol~uldlcd into working cc,lllposiLions according to this invention themselves, and in another specizlli7f -1 embodiment of the invention, liquid cu-~l~osilions co..li.;..;.~g hexavalent dllollliu may be used as posttre~tm~nt~ after application of a coating accordi-lg to this 3 0 invention but before final overcoating with a paint or the like, in order further to ihl~luve corrosion re~ist~n~e of the metal surface treated.
The other major type of coating used in the invention, employing a coating -W 0961357~5 PCTrUS95/0522S
cc,Lu~osilion inrlll-ling n~cçc~.y CO111~O11eL~7 (A') and (B') as already described above, has been found to be espeei~11y useful for treating mrt~llic sllrfarçs that are exposed to aLkali metal ions, particularly sodium such as often occurs in delGIgc.ll~, and other rl~-an~r.c, after the llc~l",~ l with a culll~,osiLion according to this invention has been 5 complPtP~ ulc~livc coatings applied to mrt~llic sl-rf~res, particularly ah~...i..l.....
f~.dbly are water incolllhlr and inhibit corrosion. However, m~tallir s--rf~res bear-ing a plulc-;live coating are often exposed to sodium ions later. It is believed that, upon e~o~,u c of some prior art coatings to sodium ions, the sodium ions orl~"li...~s at least partially replace the ~lllminllm in the formed coating, much as in an ion-ex-10 change resin; such repl~rçmPnt in turn causes the film coating to be water sensitive,by increasing its sohlbility in water.) In an effort to decrease adverse effects of allca'li metal ions on the treated sur-faces, it has been found that by c- mhininp (i) polymers and copolymers of acrylic and mPtharrylic acids and their salts having an average m~lçclllar weight of about 50,000 15 with (ii) a water soluble or dispersible polymer having at least one -OH group per polymer m( l~rul~, adverse effects from e~o~,u c of the treated surface to aLkali metal ions can be reduced. Possibly this occurs becduse the alcohol fimrtiorlality cross-links by r"l~ . riri.lil~n with the acid fimrtionc In a particularly plGr~,.lGd embodiment of this aspect of the invention, the composition cnnt~rt~d with a m~t~llic surface co...l., ;ces 2 0 water and: (A') from 0.5 to 50 gA and (B') from 0.5 to 50, and more ~lcrclably from 0.5 to 16 g/l of polyvinyl alcohol. The polyvinyl alcohol used in the invention preferably is a low molecular weight polyvinyl alcohol which is 75 - 99+ mole %
hydrolyzed, and has an average degree of poly",~ ion rangin~ from 100 - 600.
While any water soluble or rlicpercihlP polymer having at least one -OH group per polymer m-lrcllle may be employed without departing from the spirit of the in-vention, ~lGrGllcd polymers and alllUUl1l~7 thereof include the above-stated polyvinyl alcohol; from 0.3 to 16 g/l, preferably from 0.3 to 1.2 gll, of polyethylene glycol having a m- lçcular weight of from 90,000 to 900,000; from 0.5 to 16 g/l, and prefer-ably from 0.5 to 10 g/l of ~l.oxtrin, cyclo-lextrin, or a mnr1ifi~d starch.
3 0 The term "m~lifiPd starch" is one c-."".. ~l~ly known in the art. It refers to any of several water-soluble polymers derived from a starch by ~etylation, chlorination, ~id hydrolysis, or el.~yL~ic ~tion. These lG~.-Iiol-c yield starch ~retates, esters, and W 096/35745 PCT/U~.9_ha~25 ethers in the form of stable and fluid solutions and films. These starch deliv~lives useful herein are well known.
The hydroxyaLkyl starch ethers and starch esters can be obL~ ed by known eth~-rifir~fion and ~st~rifir~ti~.n pl~ cesses. These starch ethers and esters should have 5 a degree of ~ub~ irJn (hereinafter often abbreviated "D.S.") of 0.01 to 0.5, and preferably 0.1 to 0.5. As used herein D.S. means the average degree of s~lhstitl~tion of starch hydlu~yl groups per anhydroglucose unit of the r,h.omir~l modifying substitu-ent, as for çY~mrl~ a hydroxalkyl or c~l,ullyl group.
Oxidized starch can be obtained by known ~lucesses involving oxidation of 10 starch with a suitable oxitli7ing agent, as for ~.x~ )lc sodium hypochltrite7 pot~ccillm dichnJll~dle and sodium pPrrn~n~n~t~ The starch can be ~lXilli7P.~l under acid, alkaline or neutral con~lition~, and the res--lting product can contain carboxyl and carbonyl groups. Preferably the oxitli7~od starch has a "D.O." value of 0.01 to 1.0, where "D.O." refers to the llulllbel of carboxyl groups introduced per anhydroglucose unit.
15 These starch dcliv~livc~. and mPthn-lc for cll.L~ l llg thern are ~licc~ccefl in Whistler and Paschall (eds.), Starch: Chemistr~ and Technology, vol. I, (~ emiC Press, 1965), pp.
458 - 78.
Dextrins and cyclo-leYtrinc are polyc~ch~ri~lp- products of a complex nature re-sulting from the partial clegr~ tion of starch, such as corn starch, potato starch, wheat.
20 starch, and the like, with heat, as for ~Y~mrlP, by roasting with acid or Rlk~lin~. cata-lysts. Linear and hr~n~h~ extrinC are cl~ccifi~d in three types. The particular type obtained depends on the heating time, ~c~ el~Lulc, and catalyst employed in the treat-ment of the starch. These types are ~ ccifit~ as white d~Ytrinc, yellow or canary dex-trins, and British gums, and all such tl~Ytrinc are suitable herein. White and canary 25 dextrinc are ~lcre~l~,d in that British gums are brown in color. White deytrinc are preferably pregel~tini7P~l (made water soluble during m~nnf~ct7~lre)~ if nrcesc~ry, to render them more readily mixed wit'n other water soluble colll~olle~ .. Dextrins and m~tht~-lc for obtaining them are well known. See, for ~Y~mpl~7 Whistler and Paschall op. cit., vol. I, p. 421 ff and vol. II, p. 253 ff.
The starch hydrolysates useful in the c ~ ,o~ilionC of this invention are a rela-tively new class of starch m~t~ri~lc. These starch hydrolysates are made by ~.ul~je~;ling a source of starch, such as her~inhefnre m~ntion~-l, to el~ylllc or acid tre~tmt~nt or a W O 96/35745 ' PCT/U~5SI'~225 comhin~tit~n of both. It is ilL~yvl~L that the starch hydrolysate have a relatively low dextrose equivalent (hereinafter often abbreviated "D.E."). The starch hydrolysate should have a D.E. of from 2 to 35, and plere.dl~ly have a D.E. of from ~ to 25. The most p cr~-cd m~tt-ri~l~ have a D.E. within the range of 5 to 15. (The term D.E. is used herein to refer to the redllcin~ sugars content of the dissolved solids in a starch hydrolysate c,~ cssed as percent dextrose as measured by the Luff-Schoorl method[NBS Circular C40, p. 195; also appearing in Polarimetry, Saccharimetry, and theSugars published by Frederick J. Bates and Associates].) Particularly p crc--cd mo-lifi~d starches include cyclodextrin.c, which are mac-rocyclic non-re~ in~ D-glucosyl polymers co,.l;l;,.i.~P six or more D-~luco~yl residues bonded by a-(I,4) links. A more det~iled description of cyclc-lextrin.c can be found in Whistler and Paschall, op. cit., Vol. 1, pp. 209-224.
The pH of a cor-~~osilion according to this invention that contains culll~ol~ell~
(A') and (B') as n~cccs~y culllL,oncllL~ preferably is in the range from l.0 to 5.0, and more ~lcrc.~bly from 1.0 to 3.5.
In a plcfc lcd embodiment of the aspect of the invention lltili7ing nPcecs~ry cvlll~)oncllL~ (A') and (B'), the treating colll~osiliull also in~ rlPc from 0.2 to 19.0, and more preferably from 0.2 to 8.0 g~, of fluvluacids colll~vllent (C') ~rlmiYIo(l therein.
Cvlll~vnclll (C') is preferably SP~ ct~l from the group c~ of H2TiF6, H2ZrF6, 2 0 and H2SiF6, and more preferably is H2TiF6 or H2ZrF6.
Still another embodiment of the invention is a process of treating a metal with a composition ~.~ed as described above. In one embodiment of the invention, it is ~crcllcd that the aqueous coll.~osiLion as described above be applied to the metal surface and dried in place thereon. For ~Y~mplP, coating the metal with a liquid film may be accomplich~d by ;- ~---~ ;--g the surface in a cn-~ cr of the liquid compo-sition, spraying the composition on the snrfare, coating the surface by passing it between uppcr and lower roiiers with the lower roller ;.. ~.~e~l in a co"t~;"~r of the liquid composition, and the like, or by a ~lulc of m~tho-l~, P-Y~eS.C;Ve amounts of the liquid cu~ osilion that might uLIlcl wi~e remain on the surface prior to drying may 3 0 be removed before d~ying by any collvc ~icnL mPth~d, such as ~ n~ge under the influ-ence of gravity, squeegees, passing bcLwccn rolls, and the like.
If the surface to be coated is a continll~us flat sheet or coil and precisely con-trollable coating techniques such as gravure roll coaters are used, a relatively small volume per unit area of a co,-r~ lel1 co"~o.ilion may effectively be used for direct appli~tinn On the other hand, if the coating eq lipm~.nt used does not readily permit precise coating at low coating add-on liquid volume levels, it is equally effective to use a more dilute acidic aqueous co~"~o~.iLion to apply a thicker liquid coating that ct-nt~inC t'ne same amount of active ingredients. In either case, it is plGfGll~d that the total amount of active ingre~lientc of cu",~ùnents (A~, (B), and (C) and described above dried into place on the surface to be treated fall illtO the range of from 1 to 500, more ~lc;ÇGldbly from 5 to 300, still more preferably from 5 to 150, milligrams per square meter (hereinafter often abbreviated as "mg/m2") of surface area treated.Drying may be accomplich~cl by any cûnvGllient ~ntothc)~l of which many are known per se in the art; ~-x~mples are hot air and infrared radiative drying. Independ-ently, it is ~lcfcllcd that the m~xi.~ elllpcldLulc of the metal reached during drying fall within the range from 30 to 200, more preferably from 30 to 150, still more pref-erably from 30 to 75, ~ C. Also in-l.orPn(l.-ntly, it is often p~Gf~ cd that the drying be comrletetl within a time ranging from 0.5 to 300, mor~ rrçfer~hly from 2 to 50, still more ~,cre~dbly from 2 to 10, secon-lc (h~rein~h~r abbreviated "sec") after coating is comrleteA
Accul~lh~g to an ~ ;vc embo-lim~-nt of the invention, the metal to be treat-2 0 ed ~lcf~.dbly is cont~rtP~l with a cc,m~osilion prepared as ~lesc~ ;l~d above at a temper-ature within the range from 25 to 90, more plcfe.dbly from 30 to 85, still more pref-erably from 30 to 60, ~ C for a time ranging from 1 to 1800, more preferably from 1 to 300, still more preferably from 3 to 30, sec, and the metal surface thus treated is ~llhseqllently rinsed with water in one or more stages before being dried. In this em-2 5 bo-li--.,-.l, at least one rinse after LrP;~I " ,~i~l with a cu" ,l o.~il ion according this inven-tion preferably is with d~;oni7~ iCtill.ocl7 or otherwise purified water. Also in this embo-lim~nt, it is ~lc;f~ ,d that the m x;""",- Ir.~ e,~ c of the metal reached during drying fall within the range from 30 to 200, more preferably from 30 to 150, or still more p,cfc,dbly from 30 to 75, ~ C and that, indep~n(1~ntly~ drying be comrleted3 0 within a time ranging from to 0.5 to 300, more preferably from 2 to 50, still more preferably from 2 to 10, sec after the last contact of the trcated metal with a liquid before drying is cnmrlP.tf cl -W 096135745 PCTrUS95/0522S
A process according to the invention as g~-n~-rally described in its ecct-ntial fea-tures above may be, and usually preferably is, continued by coating the dried metal surface produced by the tre~tm~onf as r~çs~rihed above with a siccdlive coating or other protective co~tinp~, relatively thick as compared with the coating formed by the earlier 5 stages of a process accol lh~g to the invention as described above. Such protective co~tingC may gen~.r~11y, in connRction with fhiS invention, be sç1RctP~ and applied as known per se in the art. Surfaces thus coated have been found to have ext~ellent re-cict~n~e to subsequent corrosion, as illllctr~tpd in the examples below. Particularly ~rcr~lcd types of protective coatings for use in conjunction witn this invention in-10 clude acrylic and polyester based paints, en~mPlc, lacquers, and the like.
In a process according to the invention that includes other steps after the for-mation of a treated layer on the surface of a metal as described above and that oper-ates in an enviiul-lllent in which the discharge of hexavalent cl.lullliulll is either le-gally restrirte-l or ecnnc-mi~lly h~nr~ pped~ it is generally ~lcrellcd that none of 15 these other steps include c-~nt~rting the surfaces with any composition that co~ ,c more than, with increasing preference in the order given, l.0, 0.35, O.lO, 0.08, 0.04, 0.02, O.Ol, 0.003, O.OOl, or 0.0002 % of hexavalent ch~ .l. Examples of suitable and preferred cl-l~ull iulll free t~ are described in U. S. Patent 4,963,596.
However, in certain .cpeci~1i7t~ es7 hexavalent Chlullliulll may impart snfficiçnt 2 0 additional corrosion protection to the treated metal surfaces to justify the increased cost of using and lawfully disposing of it.
Preferably, the metal surface to be treated according to the invention is first cleaned of any c~ , particularly organic c~ ..tc and foreign metal fines and/or inclusions. Such cl~nin~ may be acco...l,1ich~d by m~tho~lc known to those 2 5 skilled in the art and adapted to the particular type of metal ~ dle to be treated.
For e~ mp1R, for galvanized steel snrf~es, the ~.ubsLId~e is most preferably cleaned wi ~ a cul.v~ .n;11 hot z~1k~iinP cieaner, then rinsed with hot water, squeegeed, and dried. For ~1..., .;... ~.~ ., the surface to be treated most preferably is first c~ fl with either an aqueous ~lk~lin~ c1e~ning solution in accordance with that ~lic~lose~1 in U.S.
3 0 Patent No. 4,762,638, ~colpola~Gd herein by rcrGlGllce, or an aqueous acidic r1.o~ning solution as ~licçlosecl in U.S. Pat. No. 4,370,173, also i~cul~vldlGd herein by lGrGlGllce.
With respect to the aqueous acidic çlP-~ning solution, it should also be noted that a =

W 096~5745 PCTrUS95/05225 source of fluorirlP such as HF may also be employed to even further ~nhzlnre thecl~z~ning process. Irrespective of the type of ~lezlnin~ solution employed, the alumin-um is then subjected to a water rinse, after which a composition in accordance with the present invention may then be coated onto the Zllt~ .,., in acco~la~ce with the 5 processes disclosed herein.
The practice of this invention may be further appreciated by consideration of the following, non-limitin~, working examples, and the benefits of the invention may be further appreciated by reference to the c~ ;sol- examples.
GROUP I
COMPONENTS (A) AND (B)~ WlTH DRY IN PLACE TREATMENTS) Test Methods and Other General Conditions Test pieces of Type 3105 ztlll",;""", were spray cleaned for 15 secontlc at 54.4~
C with an aqueous cleaner cnl-t;lit-;..~ 28 g/L of PARCO~ Cleaner 305 (collllllel~;ially available from the Parker+Amchem Division of Henkel Corp., Madison ~eight.c, 15 Michigan, USA). After clezlning, the panels were rinsed with hot water, squeegee~l, and dried before roll coating with an acidic aqueous cc, ,~osiLion as described for the individual exzlmrles and c-.",~lzl;co~ exzlmplPs below.
For this first group of eYzlmpl~s and coll.l ~l ;cOIl exzlmples7 the applied liquid composition according to the invention was flash dried in an infrared oven that pro-20 duces ~ llately 49~ C peak metal ~ ll.G. S~mples thus treated were subse-quently coated, according to the lGco...llll ~ zltions of the suppliers, with various com-mercial paints as cpecifiP-l further below.
T-Bend tests were according to ~m~riczln Society for Testing mz~t.-rizllc (herein-after "ASTM") Method D4145-83; Impact tests were accordhlg to ASTM Method D2794-84El; Salt Spray tests were according to ASTM Method B-117-90 Stzmdard;
Acetic Acid Salt Spray tests were ~colding to ASTM Method B-287-74 Standard; andmiclity tests were according to ASTM D2247-8 Standard. The Boiling water im-mersion test was pGlr~,lllled as follows: A 2T bend and a reverse impact ~l~r~ nwere ~el~lllled on the treated and painted panel. The panel was then illllll~ for 10 .I.i.---lrs in boiling water at normal ~tmnsph~ric ~ 3~ule~ and areas of the panel most ~ffectecl by the T-bend and reverse impact dcÇ~ li"nc were ~Ys....i..~cl to deter-mine the percent of the paint film nri~in~lly on these areas that had not been exfoliat-W 096135745 PCTrUS95/05225 ed. The rating is reported as a number that is one tenth of the ~Gl1ellL~ge of paint not exfoliated. Thus, the best possible rating is 10, infli~tin~ no exfoliation; a rating of 5 inr1ir~tes 50 % exfoliation; etc.
Specific Compositions 5 ExamPle 1:
5.6 parts of amorphous fumed silicon dioxide 396.2 parts of deionized water 56.6 parts of aqueous 60 % fluotitanic acid (i.e., H2TiF6) 325.4 parts of deionized water 216.2 parts of an aqueous solution c~.. l~i.. i.. ~ a ~ Lur~ of 4.1 g/l polyacrylic acid and 4.0 g/l polyvinyl alcohol F~mrle 2:
58.8 parts of aqueous 60 % fluotitanic acid 646.0 parts of ~leioni7~l water S.9 parts of amorphous fumed silicon dioxide 10.5 parts of zi~;ol~iu~l hydroxide 278.8 parts of the 10 % solution of water soluble polymer as used in FY~mrle 1.
Example 3 62.9 parts of aqueous 60 % fluotitanic acid 330.5 parts of rlei--~i7~d water 6.2 parts of amorphous fumed silicon dioxide 358.9 parts of deionized water 241.5 parts of the 10 % water soluble polymer solution as used in FY~mrle 1 Example 4 56.4 parts of aqueous 60 % fluotitanic acid 56.4 parts of deionized water 2.1 parts of Aerosil~ R-972 (a surface treated ~ per~ed silica) 667.0 parts of ~leinni7~--d water 218.1 parts of the 10 % water soluble polymer solution as used in F~r~mple 1 3 o Fx~mple S
58.8 parts of aqueous 60 % fllloti~nie acid 3.7 parts of amorphous fumed silicon dioxide W 096/35745 PCTrUS95/OS225 10.3 parts of ~ ;olliulll basic carbonate 647.7 parts of deionized water 279.5 parts of the 10 % solution of water soluble polymer as used in Example 1 Example 6 5 52.0 parts of aqueous 60 % fluotitanic acid 297.2 parts of deionized water 3.3 parts of amorphous fumed silicon dioxide 9.1 parts of ~ ;olliulll basic carbonate 273.6 parts of deionized water 364.8 parts of the 10 % solution of water soluble polymer as used in F.~mple 1 Example 7 11.0 parts of fumed amorphous silicon dioxide 241.0 parts of deionized water 114.2 parts of 60 % aqueous fl-lotit~nic acid 15 633.8 parts of an aqueous cc,~ osilion prepared from the following ingredients:
5.41 % of CrO3 0.59 % of pearled corn starch 94 % of water Example 8 666.0 parts of cl~-ioni7P~l water 83.9 parts of 60 % aqueous fluotitanic acid 5.3 parts of Cab-O-Sil~ M-5 fumed amorphous silicon dioxide 14.8 parts of zh~;olliulll basic carbonate 230.0 parts of RDX 68654TM (also known as RIX 95928T~S) epoxy resin dispersion commercially available from Rhône-Poulenc, co.. ~ 40 % solids of poly-mers of prer3O...i..n..lly diglycidyl ethers of bisphenol-A, in which some of the epoxide groups have been co~ Led to hydroxy groups and the polymer mol.-.clll~.s are phosphate capped r,x~ lc g 30 656.0 parts of deionized water 183.9 parts of 60 % aqueous fluotitanic acid W 096/35745 PCTrUS95/05225 5.3 parts of Cab-O-SillM M-5 fumed amorphous silicon dioxide 14.8 parts of zil~eolliulll basic carbonate 240.0 parts of Accumer~ 1510, a cc,ll.~ ;ially available product from Rohm &
Haas co~ g 25 % solids of polymers of acrylic acid with a molecular weight of 60,000 Example 10 636.2 parts of ~lF.ioni7:F.cl water 83.7 parts of 60 % aqueous flllotit~nic acid 5.3 parts of Cab-O-SilTM M-5 fumed amorphous silicon dioxide 14.6 parts of ~i,colliul" basic carbonate 37.6 parts of the 10 % solution of water soluble polymer as used in Example 1 222.6 parts of ~cumFrTM 1510, a commercially available product from Rohm &
Haas co~ 25 % solids of polymers of acrylic acid with a molec~ r weight of 60,000 For each of FY~mrl~.s 1 - 6 and 8 - 10, the ingredients were added in the order inAic~te.~l to a c~mt~inFr provided with stirring (Glass containers are susceptible to ehFmie~l attack by the compositions and generally should not be used, even on a lab-oratory scale; c.~..l;.il-F..x of ;~ r~ c st~inlr.ss steels such as Type 316 and c(J.~ F-.x made of or fully lined with ,c~isL~,L plastics such as polymers of tetrafluoroethene or 20 chlo~LIinuoroethene have proved to be s~ticf~tory.) In each of these FY~mples ex-cept F.Y~mrl~F 4, after the ~AAition of the silica co~lpollc~L and before the addition of the subsequently listed cu",po,lenL~, the ,.li~Lu,e was heated to a IG111~C1dlU1G in the range from 38 - 43 ~ C and m~int~inFcl within that range of telll~FldLu,cs for a time of 20 - 30 ...i....l~.c. Then the ~ u~e was cooled to a Lclll~cla~ul~, below 30~ C, and 25 the ,~ ;;g ingredients were stirred in without ~Mition~l hr.~ting, until a clear solu-tion was obtained after each ~AAiti~m For FY;~ 1r 4, the SiO2 used was surface mnAifiF~l with a silane, and because of its hy~ Jphobic nature, the 111i~LU1C COIII71;;l;llg this form of silica was heated for 1.5 hours at 70~ C to achieve ~ IG~1~;Y. The ,~~i;.-g steps of the process were the 3 0 same as for FY~mrle 1.
For FYzt.l.l)lr. 7, the first three ingredients listed were miYed together and main-tained at 40 + 5 ~ C for 20 - 30 ~ ..;....~s with stirring and then cooled. In a sep~r~tF

-WO 96135745 PcTluS9-~J~522s cont~inPr, the CrO3 was dissolved in about fifteen times its own weight of water, and to this solution was added a slurry of the corn starch in twenty-four times its own weight of water. The mixture was then ,-~ for 90 minllteC with gentle stirring at 88+6 ~ C to reduce part of the hexavalent Chr~llliUlll content to trivalent cll,~lll.ulll.
5 Finally, this mixture was cooled with stirring and then added to the previously pre-pared heated mixture of fluotitanic acid, silicon dioxide, and water. This composition is used in the manner known in the art for compositions c-",l~ lg hexavalent and tri-valent chl~,l,.iu", and tli~p~r~ed silica, but it is much more stable to storage without phase separation.

Co~ ~dLiv~ Exdmple 1 18.9 parts of aqueous 60 % fluotitanic acid 363.6 parts of the 10 % solution of water soluble polymer as used in FY~mrle 1 617.5 parts of deionized water Cc,lllpaldLive Example 2 18.9 parts of aqueous 60 % fluotitanic acid 71.8 parts of the 10 % solution of water soluble polymer as used in FY~mrle 1 909.3 parts of d~-ioni7~-~l water For Coll~ Livt; FY~rnrles 1 and 2 the col..~ollents were added together with ~gitz~tic)n in the order inr1ir~t~-tl, with no heating before use in treating metal s~ rçc Add-on mass levels, specific paints used, and test results with some of the compositions described above are shown in Tables 1 - 5 below.

CA 02220419 l997-ll-06 W 096/3574~ PCTrUS9~ 3>25 TABLE l: Panels Painted with PPG DuracronTM lO00 White Sin~zle Coat Acrylic Paint - T~ l Boilin~ Water Coating HAc Salt ~nmirlity 2T Bend Impact Wei~ht Spray 1008 Hrs.
504 Hours -P.y~mrl~ 1 9 10 65 mg/m e 0-lS Vf9 asTi sO-ls 9 lO 43 mg/m e 0-15 Vf9 asTi sO-ls Col~ , 5 7 39 mg/m e 0-lS D9 F.Y~mplt~ 1 as Ti s 0 25 0 0 27 mg/m2 e 0-lS D9 as Ti s 0-2S
Co",~ ive 7 8 65 mg/m2 e 0-lS Vf9 20PY~mpl~o 2 as Ti s O ls 4 6 29 mg/m e 0-lS Fm9 as Ti s O_lS

TABLE 2: Panels Painted with LillyTM Black Sin~le Coat Polvester Salt HAc Salt Spray Treat- Boilin~ Water Coating Spray 504 1008 Humidity ment 2T Bend Impact Wei~ht Hours Hours 1008 Hrs.
Example 10 10 54 mg/m2 e O-1' e N
3 5 2 .as Ti s N s N Vf9 Example lOlO 64 mg/m2 e 0-2' e o-1a 3 as Ti s 0-2- s N V~9 CA 022204l9 l997-ll-06 TABLE 3: Panels Painted vith Lillv~M Colonial White Sin~le Coat Polvester Salt HAc Salt Spray Treat- Boilinq Water Coating Spray 504 1008 Humidity ment 2T Bena Im~act Weiqht Hours Hours 1008 Hrs.
0 Example 4 5 8 65 mg/~e N e N
as Tis N s N V~
Example 5 10 10 22 mg/~e N e N
as Tis N s N V~
Example 5 10 10 54 mg/~e N e N
s N s N V~
Example 6 lO 10 22 mg/~e 0-1' e N
s N s N V~
Example 6 10 10 54 mg/~e 0-1' e N
s N s N V~
Example 8 9.8 10 12 mg/~e N e N
s 0-1' s N N
Example 8 9.6 10 24 mg/~e N e N
s 0-1' s N N
Example 9 10 10 11 mg/~e N e N
s o--1~s o--r N
Example 9 9.8 10 24 mg/~e 0-1 e N
3 5 s 0-1's 0-1 N
Example 10 9.8 9.817 mg/~e 0-1' e N
s 0-1' s N V~
Example 10 9.9 10 25 mg/~e 0-1' e N
s 0-1~ s N V~
Example 10 9.9 10 33 mg/~e 0-1' e N
s 0-18 s N V~

TABLE 4: Panels Painted with Valspar/DesotoTM White Sin~le Coat Polvester Salt HAc Sal t Spray Treat-BoilinqWater Coating Spray 1008 1008 Humidity ment 2T BendImpact Weiqht Hours Hours1008 Hrs.
10Example10 10 39 mg/m2 e 0-1' e N
2 as Ti s 0 _ 12 s N Vf 9 Example 10 10 48 mg/m2 e 0-1- e N
2 as Ti s 0 - 1- s N Vf 9 15Example10 10 70 mg/m2 e 0-25 e N
2 as Ti s 0 - 1- s N Vf 9 Example 10 10 87 mg/m2 e N e 0-1-2 0 2 as Ti s 0 - 1- s N Vf 9 Example 10 10 29 mg/m2 e 0-2- e N
3 as Ti s 0 - 1- s N Vf 9 25Example10 10 42 mg/m2 e 0-1- e N
3 as Ti s 0 - 1- s N Vf 9 Example 10 10 57 mg/m2 e 0-1 e N
3 as Ti s 0--1- s N Vf 9 Example 10 10 82 mg/m2 e 0-2- e 0-15 3 as Ti s 0-2' s N Vf9 Example 7 10 65 mg/m2 e 0-1' e N
3 5 4 as Ti s 0 - 1- s N Vf 9 TABLE 5: Panels Painted with ValsparTM Colonial White Sin~le Coat Polyester Sal t HAc Sal t Spray 45Treat-BoilinqWater Coating Spray 504 1008 Humidity ment 2T BendImpact Weiqht Hours Hours1008 Hrs.
Example 10 10 54 mg/m2 e N e N
2 as Ti s N s N E m9 Example 10 10 64 mg/m2 e 0-15 e 0-15 3 as Ti s N s 0 - 1- Fm9 -W096/35745 PCTrUS9~ 225 The storage stability of the compositions according to all of the P~mrles above except FY~mrle 2 was so good that no phase sep~r~tion could be observed after at least 1500 hours of storage. For F.Y~mrle 2, some settling of a slight amount of ap-parent solid phase was observable after 150 hours.
GROUP II
COMPONENTS (A) AND (B). WITH SPRAY TREATMENT) To obtain the results reported below, an ~ltprn~tive process of treating the metal surfaces according to the invention and different ~ll.."il,."" alloys were used.
SpP~rifir~lly, in part I of this Group, test pieces of Type 5352 or 5182 ~ were spray clP~ne-l for 10 seconds at 54.4~ C with an aqueous cleaner C~JIII;1;1~;1~g 24 g/L
of PARCO(~ Cleaner 305 (c~.llllllr~.l~-;~lly available from the Parker+~mrhpm Division of Henkel Corp., M~ on ~eight~, Mirilig~n~ USA). After rle~ning~ the panels wererinsed with hot water; then they were sprayed with the, e~e~;live tre~tmrnt solutions acco.dillg to the invention, which were the same as those already ~P.srrihed above with the same Fx~mple Number, except that they were further diluted with water to thecollct;~ dLion shown in the tables below, for S seconds; and then were rinsed s~lcces~ivt;ly with cold tap water and deioni7e-1 water and dried, prior to p~inting The "OT Bend" column in the following tables reports the result of a test procedure as follows:
1. Fe.Çc,l.-l a 0-T bend in accordance with ASTM Method D4145-83.
2. Firmly apply one piece of ~610 Scotch(~) tape to the area of the test panel with the O-T bend and to the ~dj~rPnt flat area.
3. Slowly pull the tape off from the bend and the ~di~rent flat area.
4. Repeat steps 2 and 3, using a fresh piece of tape for each repetition, until no additional paint is removed by the tape.

5. Report the m~imllm rlict~nre from the 0-T bend into the flat area from which paint removal is observed according to the scale below:

W 096/35745 PCT/U~9SJ'~5~25 Paint loss in mm Rating 0 5.0 0.20 4.9 0.30 4.8 0.8 4.5 1.6 4.0 2.4 3.5 3.2 3.0 4.0 2.5 4.8 2.0 5.6 1.5 6.4 1.0 7.2 0.5 >7.2 0 lS The "Ninety Minute Steam Exposure" columns of the tables below report the results of tests ~elrvlllled as follows:
1. Expose the painted .c~mples to steam at a temperature of 120~ C steam for 90 minutes in a ~lCS~ulc cooker or autoclave.
2. Cro,cch~tr-h the painted sample - two perpe~-lir~ r cuts; a Gardner crocch~trh 2 0 tool with 11 knife edges spaced 1.5 mm apart was used.
3. Firmly apply #610 ScotchTM tape to the c,osch ~Irh~l area and remove tape.
4. F~ minf the crosch~tr-h~l area for paint not removed by the tape and report a number lcp,-,senl;--~ one-tenth of the pe,~;cl,~ge of paint rem~ining 5. Using a microscope at 10 - 80 times m~gnific~tion, visually observe crosch~trh.o~i area for blictrrin~, and rate size and density of blisters.
The "15 Minute Boiling DOWFAX~M 2Al TmmPncion" columns of the tables below report the results of tests pc,rulllled after l,~ l as follows:
1. Prepare solution of 1 ~o by volume of DOWFAXIM 2Al in deionized water and bring to boil.
3 0 2. T.. ~. ~e painted test panels in the boiling solution ~lG~ucd in step 1 and keep there for 15 ...i....l~s, then remove panels, rinse with water, and dry.
DOWFAX~ 2A1 is cv~ "c;~iially available from Dow Chtornir~l and is de-scribed by the supplier as 45 % active sodium dodecyl L~Lcllyloxide lliclllf n~t~ The "Cross Hatch" test after this l~c~ .l was made in the same way as ~esrrihecl above CA 022204l9 l997-ll-06 W 096/3574~ PCT~US95/05225 for steps 2 - 4 after "Ninety Minute Steam E~o~ ;". The "Reverse Impact" test was made as described in ASTM D2794-84El (for 20 inch pounds impact), then proceed-ing in the same way as described above for steps 3 - 4 after "Ninety Minute Steam Exposure". The "Fe~th~-rin~" test was ~lÇolllled as follows: Using a utility knife, 5 scribe a slightly curved "V" on the back side of the test panel. Using sc-icsnrc, cut up about 12 millimt-terc from the bottom along the scribe. Bend the inside of the V away from side for testing. Place sample in a vise and, using pliers, pull from the folded section with a slow continuous motion. Ignore the part of the panel between the top edges nearest to the vertex and a line parallel to the top edge but 19 mm away from 10 it. On the r~m~in-ler of the panel, lllea~ulc; to edge of fe~thPring in millim~terc Re-cord the largest value observed.
The results of tests according to these procedures are shown in Tables 6 - 8 below.

TABLE 6: 5352 AlloY Panels Painted with Vals~arTM S-9009-139 Paint Inven- Concen- ~H Coating OT Bend Ninety Minute tion tration Weiaht Steam Ex~osure Compo- Cross Blist-sition Hatch erinq Example 1~ 2.7 4.0 5 lO Very 1 mg/m2 ~ew, 2 5 as Ti small-medium Example 1% 3.2 11.4 5 lO ~ew, 1 mg/m2 small as ~i Example 3% 2.5 2.3 5 lO very 1 mg/m2 few, as Ti very ' small Clean N/A 1.5 lO ~ew, only medium (Com-pari-son) CA 022204l9 l997-ll-06 W 096/35745 PCTrUS9S/05225 TABLE 7: 5352 Allov Panels Painted with ValsDarlM S-9009-154 Paint 5 Inven- Concen- E~ Co~ting OT Bend Ninety Minute tion tration Weiqht Steam ExPosure Compo- Cross Blist-sition Hatch erinq lOExample 1% 2.9 4.2 5 9-lO Very 1 mg/m2 few, as Ti small Example 3% 2.7 2.6 5 9-lO very 1 mg/m2 few, as Ti very TABLE 8: 5182 alloY Panels Painted with Vals~arTM S-9835002 Paint 20 Inven- Concen- E~ Coating 15 Minute Boiling DOWFA~
tion tration Weiqht 2A1 Immersion sitlon Cross Reverse Feathering Hatch Impact 25Example 1 % by 2.9 7.9 mg/~ lO lO 0.35 mm 1 weight as Ti In part II of this Group, Type 5352 ~ .. n was used, and the process se-30 quence used in part I, except for final drying, was used but was then followed by passing the test pieces, still wet from the deionized water rinse after contact with a composition ~cording to this invention, through power driven squeegee rolls arran~e-l so that the test pieces passed through the squeegee rolls in a h~l~ont;ll position im-m~ t~ly after being sprayed liberally with the final tre~tm.-nt liquid composition at a telll~ ulc of 60~ C before being dried. In Examples 11 and 13 the LlC~l.. '~t liquid in this final stage was simply d.-ioni7lod water with a con-lucLivily of not more than 4.0 ~ ml3n~/cm, while in F.Y;....~ 12 the LIC~ ..I Iiquid in this final stage was obtained by mixing 35 ml of Parcolene~ 95AT and 2.0 rnl of Parcolene~M 88B with 7 liters of deionized water and had a pH of 5.18 and a conducliviLy of 56 IlSie-4 0 mens/cm. (Both Parcolene~ products noted are cul~ ,ially available from the Par-ker+~mrhPm Div. of Henkel Corp., ~licon ~ei,e~ht~ hig~n ) This latter type of final Llc;~ ll liquid is an çx~ . of one cf l.l;.i..;..g polymers and/or copolymers of one or more x-(N-Rl-N-R2-~minomPthyl)-4-llydlu~y-styrenes as already described above.

W 096/35745 PCTrUS951~5~25 Concentrate II-II used in each of Examples 11 - 13 had the following composition:
1892.7 parts of deionized water 83.7 parts of 60 % aqueous fluotitanic acid 5.3 parts of Cab-O-SilTM M-5 fumed amorphous silicon dioxide 18.3 parts of zirconium basic carbonate.
These ingredients were simply mixed togeth~o-r with llrccl.~-iç~l agitation in the order shown, with a pause after each addition until the solution became optically clear. Al-though the partial mixture was not Lld~ a-tnt immP~ t~ly after ~d-lition of the silicon 10 dioxide, it became clear after a few minntec of mixing, even without any hP~ting The working solution for FY~mples 11 and 12 was ~-c~d-~,d by rlilntinp~ 200 grams of the concentrate II-II, along with sufficient sodium c~l,olldLc to result in a pH
of 2.92 + 0.2, to form 6 liters of working composition. For F.x~mrlr 13, the working solntion was made in the same way, except that it also co~ S grams of a 15 c~ e~ t~cl polymer solution made according to the directions of column 11 lines 39 - 49 of U.S. Patent 4,963,596, except as follows: The plcpalaLion was carried out on a ~lbsl;1..li~lly lOEger scale; the pl~lLions of ingredients were rh~n~d to the follow-ing: 241 parts of Propasol~ P, 109 pOEts of Resin M, 179 pOEts of N-methyl~lnr~m-ine, 73.5 parts of aqueous 37 % fc-~m~kl~hyde, and 398 pOEtS of deioni7~ water, of 20 which 126 pOEts were reserved for a final ~dtlition not described in the noted patent, with the rrm~in-l.or used to slurry the N-methylp~lnc~mint-- as noted in the patent; and the telllpcldLulc noted as 60 - 65 ~ C in the patent was reduced to 57~ C.
The dried test pOEnels were then coated with ValspOE~ 9009-157 paint accord-ing to the directions of the paint supplier, and the paint coated panels were tested as 25 described for the tests of the same name in part I of Group II. Results OEe shown in Table 9.

W 096135745 PCTrUS95/05225 FY~n1P~? mg of Ti/m2 O-T Bend 90 Minute Steam F~ --Number Cross Hatch Bli~

1 1 3.6 4.5 10 4.5 12 4.6 4.9 10 4.5 13 5.4 4.8 10 4.0 GROUP m. W~H NECESSARY COMPONENTS (A') AND (B') Example 14 A first concentrate was made by mixing 750 parts of tap water and 274 parts of AcrysolTM A-l, a commercially available product from Ro_m and Haas c~nt~ining25 % solids of polymers of acrylic acid with a mol~c~ r weight of less than 50,000.
15 A second con~-e.~ te was made by mixin~, in a cont~in~r scpdldLe from that used for the first co~--e~ dle 951.3 parts of tap water and 66.7 g/l of Goh.~nol~M GLO-5, a ccmm~-cially available product from Nippon Gohsei which is a low m~ L-nl~r weight polyvinyl alcohol; the latter was added to the tap water with stirring at a slow and controlled flow, after which the ICl.l~?CldLulc was increased to 49 - 54 ~ C for 30 min-2 0 utes with slow stirring until all was dissolved.
An amount of these cs~n~e~-l.dtcs equal, for each concentldle separately, to 6 volume % of the final volume of collll,osilion ready for treating a metal surface acc.,ldillg to this invention, was then added with stirring at ambient Ir....p~.".l...G to a large excess of water, and after ~d~lition of bot_ concelllldlGs, additional water was 25 added to reach the final volume of LlrA~ ...l composition, w_ich contained 4.1 g/l of polyacrylic acid and 4.0 g/l of polyvinyl ~ ,h- l This cc. o~ilion was then c-nt~r.t~ with an ~1.. ;... surface by dipping or spraying for a time from 30 to 60 secon-lc, after w_ich time the surfaces treated were removed from contact with the treating composition, allowed to dry in the ~mhient 3 0 ~ S~ G without rinsing, and then baked in a warm air oven at 88~ C for S ~ lrc to ~imnl~t, c~ ;;al OpGldlillg con-liti~ n~. The s~lrf~--es thus ~lc~Gd were painted W096/35745 . PCTnUS95/05225 with col.vc~ n~l paints.
Examples 15 - 20 In each of these eY~mplP,s, the treating culllpo~i~ion is prepared in the same general manner as in F~x~mpl~ 14, by making separate concentrates of the hydroxyl S group co..~ .;..g polymer and polyacrylic acid co~ olle.l~, mixing an apl)r~liate amount of these conccn~ldLcs with a larger volume of water, adding any additional Colll~ol~clll~ used, and finally adjusting to the final desired volume or mass by the ad-dition of more water. These compositions are then applied to ~ ",;""", surfaces in the same manner as described for F.x~mple 14. The specific active ingredients and 10 con~çntr~fiorl~ or amounts thereof in the llc,.l",~,..t composition for each ex~mple are as follows:
Example 15: 4.1 g/l of Acrysol~M A-l; 4.0 g/l of GohsenollM GLO-5; and 1.2 g/l of hto,x~flllo,~ ;ol~ic acid.
Example 16: 4.1 g/l of AcrysolTM A-l and 0.6 g/l of polyethylene glycol having a molec~ r weight of less than about 600,000.
Example 17: 4.1 g/l of Acrysol~M A-l; 0.6 g/l of polyethylene glycol having a molec-ular weight of less than about 600,000; and 1.2 g/l of hexafluolo;ci.conic acid.Example 18: 4.1 g/l of AcrysolTM A-l and 0.8 g/l of dextrin.
Example 19: 4.1 gll of AcrysolTM A-l; 0.8 g/l of dextrin; and 1.2 g/l of hexafluoro~i-2 0 tanic acid.
ExamPle 20: 651.4 parts of deinni7~1 water; 83.7 parts of 60 % aqueous fluotitanic acid; 5.3 parts of Cab-O-SilTM M-5 fumed amorphous silicon dioxide; 14.6 parts of ~U-;olliulll basic C~LIoll~c; 200.0 parts of ~c,--m~rTb~ 1510, a cullllllcl.:ially available product from Rohm and Haas co..l;1il,;,.f~ 25 % solids of polymers of acrylic acid with a mnl~c~ r weight of about 60,000; and 55.0 parts of ~Toh~PnolTM GLO-5.

Claims (40)

The invention claimed is:

1. An aqueous liquid composition suitable for treating aluminum and alloys thereof, said composition consisting essentially of water and:
(A') a water soluble or dispersible polymer component selected from the group consisting of polyvinyl alcohol, polyethylene glycol, modified starch, and mixtures thereof and (B') a component selected from the group consisting of polymers and copolymersof acrylic and methacrylic acid and their salts; and, optionally, one or more ofthe following components:
(C') a component selected from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H3AlF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and mixtures thereof;
(D') a component selected from the group consisting of the water insoluble oxides, water insoluble hydroxides, water insoluble carbonates, and water insoluble elemental forms of all of titanium, zirconium, hafnium, boron, aluminum, silicon, germanium, and tin; and (E') a component selected from the group consisting of water soluble oxides, water soluble carbonates, and water soluble hydroxides of all of Ti, Zr, Hf, B, Al, Si, Ge, and Sn, the amounts of components (A) and (B) being sufficient to form on at least one type of surface fo aluminum or aluminum alloys a coating that increases the resistance of the surface to corrosion in alkaline environments, compared with an otherwise identically chosen and treated surface, except for omission of treatment with said aqueous liquid composition.

2. An aqueous liquid composition according to claim 1 having a pH value from about 1.0 to about 5.0 and consisting essentially of water and:
(A') from about 0.5 to about 50 g/l of a water soluble or dispersible polymer selected from the group consisting of polyvinyl alcohol, polyethylene glycol, modified starch, and mixtures thereof;
(B') from about 0.5 to about 50 g/l of polymers and copolymers of acrylic and methacrylic acid and their salts;
(C') from about 0.01 to about 7 M total of fluroacid selected from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H3AlF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and mixtures thereof; and, optionally, one or more of the following components:
(D') a component selected from the group consisting of the water insoluble oxides, water insoluble hydroxides, water insoluble carbonates, and water insoluble elemental forms of all of titanium, zirconium, hafnium, boron, aluminum, silicon, germanium, and tin and (E') a component selected from the group consisting of water soluble oxides, water soluble carbonates, and water soluble hydroxides of all of Ti, Zr, Hf, B, Al, Si, Ge, and Sn.

3. An aqueous liquid composition according to claim 2 wherein component A' is polyvinyl alcohol.

4. An aqueous liquid composition according to claim 3 wherein component (A') is polyacrylic acid having an average molecular weight of about 50,000.

5. An aqueous liquid composition according to claim 4 wherein said polyvinyl alcohol has a degree of polymerization from about 100 to about 600.

6. An aqueous liquid composition according to claim 3 wherein component (C') is H2ZrF6, H2TiF6, or a mixture thereof.

7. An aqueous liquid composition according to claim 6 wherein component (B') is polyacrylic acid having an average molecular weight of about 50,000.

8. An aqueous liquid composition according to claim 7 wherein said polyvinyl alcohol has a degree of polymerization from about 100 to about 600, and is present in an amount of from about 0.5 to about 16 g/l.

9. An aqueous liquid composition according to claim 1 wherein component (A') is polyethylene glycol.

10. An aqueous liquid composition according to claim 9, wherein component (B')is polyacrylic acid having an average molecular weight of about 50,000.

11. An aqueous liquid composition according to claim 10 wherein said polyethylene glycol has a molecular weight of from about 90,000 to about 900,000and is present in an amount of from about 0.3 to about 16 g/l.

12. An aqueous liquid composition according to claim 2 wherein component A' ispolyethylene glycol having a molecular weight of from about 90,000 to about 900,000 and is present in an amount of from about 0.3 to about 16 g/l, and said fluoroacid is H2ZrF6, H2TiF6, or a mixture thereof.

13. An aqueous liquid composition according to claim 12, wherein component (B') is polyacrylic acid having an average molecular weight of about 50,000.

14. An aqueous liquid composition according to claim 1 wherein component A' ismodified starch.

15. An aqueous liquid composition according to claim 14, wherein component (B') is polyacrylic acid having an average molecular weight of about 50,000.

16. An aqueous liquid composition according to claim 15 wherein said modified starch is a cyclodextrin and is present in an amount of from about 0.5 to about 16 g/l.

17. An aqueous liquid composition according to claim 2 wherein component (A') is modified starch present in an amount of from about 0.5 to about 16 g/l, and component (C') is H2ZrF6, H2TiF6, or a mixture thereof.

18. An aqueous liquid composition according to claim 17, wherein component (B') is polyacrylic acid having an average molecular weight of about 50,000.

19. An aqueous liquid composition according to claim 1 having a pH in the range from about 1.0 to 5Ø

20. An aqueous liquid composition according to claim 2 having a pH in the range from about 1.0 to 3.5.

21. A process for treating aluminum and alloys thereof comprising contacting said aluminum with an aqueous liquid composition comprising water and:
(A') from about 0.5 to about 50 g/l of a water soluble or dispersible polymer selected from the group consisting of polyvinyl alcohol, polyethylene glycol, modified starch, and mixtures thereof and (B') from about 0.5 to about 50 g/l of polymers and copolymers of acrylic and methacrylic acid and their salts; and, optionally, one or more of the following components:
(C') a component selected from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H3AlF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and mixtures thereof;
(D') a component selected from the group consisting of the water insoluble oxides, water insoluble hydroxides, water insoluble carbonates, and water insoluble elemental forms of all of titanium, zirconium, hafnium, boron, aluminum, silicon, germanium, and tin; and (E') a component selected from the group consisting of water soluble oxides, water soluble carbonates, and water soluble hydroxides of all of Ti, Zr, Hf, B, Al, Si, Ge, and Sn.

22. A process according to claim 21, wherein the aqueous liquid composition comprises water and:
(A') from about 0.5 to about 50 g/l of a water soluble or dispersible polymer selected from the group consisting of polyvinyl alcohol, polyethylene glycol, modified starch, and mixtures thereof;
(B') from about 0.5 to about 50 g/l of polymers and copolymers of acrylic and methacrylic acid and their salts;
(C') from about 0.01 to about 7 M total of fluroacid selected from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H3AlF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and mixtures thereof; and, optionally, one or both of the following components:
(D') a component selected from the group consisting of the water insoluble oxides, water insoluble hydroxides, water insoluble carbonates, and water insoluble elemental forms of all of titanium, zirconium, hafnium, boron, aluminum, silicon, germanium, and tin and (E') a component selected from the group consisting of water soluble oxides, water soluble carbonates, and water soluble hydroxides of all of Ti, Zr, Hf, B, Al, Si, Ge, and Sn.

23. A process according to claim 21 wherein component (A') is polyvinyl alcohol.

24. A process according to claim 23 wherein, in said aqueous liquid composition, component (B') is polyacrylic acid having an average molecular weight of about 50,000.

25. A process according to claim 24 wherein said polyvinyl alcohol has a degree of polymerization from about 100 to about 600 and is present in the aqueous liquid composition in an amount of from about 0.5 to about 16 g/l.

26. A process according to claim 22 wherein component A' is polyvinyl alcohol and said fluoroacid is H2TiF6 or H2TiF6.

27. A process according to claim 26 wherein, in said aqueous liquid composition, component (B') is polyacrylic acid having an average molecular weight of about 50,000.

28. A process according to claim 27 wherein said polyvinyl alcohol has a degree of polymerization from about 100 to about 600 and is present in said aqueous liquid composition in an amount of from about 0.5 to about 16 g/l.

29. A process according to claim 21 wherein component (A') is polyethylene glycol.

30. A process according to claim 29 wherein, in said aqueous liquid composition,component (B') is polyacrylic acid having an average molecular weight of about 50,000.

31. A process according to claim 30 wherein said polyethylene glycol has a molecular weight of from about 90,000 to about 900,000 and is present in said composition in an amount of from about 0.3 to about 16 g/l.

32. A process according to claim 22 wherein component (A') is polethylene glycolhaving a molecular weight of from about 90,000 to about 900,000, and is present in said aqueous liquid composition in an amount of from about 0.3 to about 16 g/l, and said fluoroacid is H2ZrF6 or H2TiF6.

33. A process according to claim 32 wherein, in said aqueous liquid composition,component (B') is polyacrylic acid having an average molecular weight of about 50,000.

34. A process according to claim 21 wherein component (A') is modified starch.

35. A process according to claim 34 wherein, in the aqueous liquid composition, component (B') is polyacrylic acid having an average molecular weight of about 50,000.

36. A process according to claim 35 wherein said modified starch is a cyclodextrin and is present in an amount of from about 0.5 to about 16 g/l.

37. A process according to claim 22 wherein component (A') is modified starch present in said composition in an amount of from about 0.5 to about 16 g/l, and said fluoroacid is H2TiF6.

38. A process according to claim 37 wherein, in said aqueous liquid composition,component (B') is polyacrylic acid having an average molecular weight of about 50,000.

39. A process according to claim 21, wherein the aqueous liquid composition has a pH in the range from about 1.0 to 5Ø

40. A process according to claim 22, wherein the aqueous liquid composition has a pH in the range from about 1.0 to 3.5.