Note: Descriptions are shown in the official language in which they were submitted.
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Description
PRECOAT CONDITIONING TREATMENT FOR AUTODEPOSITION
.
F~T n OF T~lF. INVF~TION
This invention relates to the use of liquid, usually aqueous, solutions or disper-
sions in which active metal surfaces of inserted objects are coated with an adherent poly-
mer film that increases in thickness the longer the metal object ,~l-lah,s in the bath, even
though the liquid is stable for a long time against spontaneous precipil~Lion or floccula-
tion of any solid polymer, in the ~bsence of contact with active metal, i.e., metal that
~ol IlA~u~ly begins to dissolve at a sub~ lial rate when introduced into the liquid so-
lution or dispersion. Such compositions, and processes of rollllhlg a coating on a metal
surface using such compositions, are commonly denoted in the art, and in this specifica-
10 tion, as "autodeposition" or "autodepositing" compositions, dispersions, ~m~ iQn~, sus-
pensions, baths, solutions, processes, methods, or a like term. Autodeposition is often
collll~Led with electrodeposition, which can produce very similar adherent films but re-
quires that metal or other objects to be coated be connected to a source of direct current
electricity for coating to occur. No such external electric current is used in autodeposi-
tion.
Autodeposition compos;Lions previously known in the art are effective for coatingmany metals of practical interest, but it has been observed that allt;llll)Lillg autodeposi
tion
coating of most zinc-rich metal surfaces such as galvanized steel often results in coatings
with many small "pinholes" or larger blisters. Such coatings are usually regarded as aes-
thetically llnplç~ing and often fail to provide the protection against the en~/hulllnel~L thatis normally wanted from autodeposition co~ting~ d~lcing or çl;,.,i~ g the formation
of pinholes or larger blemishes in autodeposited coatings, particularly on ~hlcireloLIs sur-
faces, more particularly galvanized steel or some variation thereof, is a major object of
this invention.
DESCRIPTIQN OF RELATED ART
Autodeposition has been in colll,ll~ ,ial use on steel for about thirty years and is
now well e~L~blished for that use. For details, see for example, U. S. Patents 3,592,699
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of July 13, 1971 to Sleil~ er et al.; 4,108,817 of Aug. 22, 1978 and 4,178,400 of Dec.
11, 1979, both to Lochel; 4,242,379 of Dec~ el 30, 1980 and 4,243,704 of Jan. 6, 1981,
both to Hall et al.; and 5,342,694 of Aug. 30, 1994 to Ahmed. (The ~li.eclosl-res of all of
these ;..~ ,ly above noted U. S. Patents, except to the extent that they may be incon-
5 sistent with any explicit ~ herein, are hereby incorporated herein by reference.)
However, p.~Lion of CGAI;ll,~,.'. free from flaws on more electro~hPmic~lly active sub-
strates such as zinc has continued to prove çh~llPn~iny especially when using an often
p-Gr~ -~;d r~ ~ ' type of autodeposition resin, an internally stabilized crystalline copol-
ymer of vinylidene chloride.
10 DESCRIPTION OF THE INVENTION
General Principles of Description
Except in the claims and the operating examples, or where otherwise ~lessly
indicated, all numerical q~ntitip~s in this description intlic~ting amounts of material or
conditions of reaction and/or use are to be understood as modified by the word "about"
15 in describing the broadest scope of the invention. Practice within the numerical limits
stated is generally p t;rt: -~d, however. Also, unless e,~ ~e~ly stated to the cGllLl~y: per-
cent, "parts of', and ratio values are by weight; the term "polymer" in~ des "oligomer~",
"copolymer", "terpolymer", and the like; the description of a group or class of materials
as suitable or p-t;r~--ed for a given purpose in connecl;on with the invention implies that
20 mixtures of any two or more of the ~--~;---be- ~ of the group or class are equally suitable or
p.ere,led; description of con~ Pnts in rhPmic~l terms refers to the con.etit~-çnts at the
time of ~ litir~n to any combination specified in the description, and does not necçce~rily
preclude chemical interactions among the cone~ .çnt~ of a mixture once mixed; specifi-
cation of m~tP.ri~le in ionic form implies the plesellce of sufficient counterions to produce
25 electrical neutrality for the composition as a whole, and any counterions thus implicitly
specified preferably are selected from among other conetit~lçnte explicitly specified in
ionic form, to the extent possible; otherwise such counterions may be freely selected, ex-
cept for avoiding counterions that act adversely to the objects of the invention; and the
term "mole" and its variations may be applied to ionic, chPmic~lly unstable neutral, or
30 any other chemical species, whether actual or hypothetical, that is specified by the types
of atoms present and the number of each type of atom inclll(led in the unit clPfine-l, as
well as to substances with well defined neutral molecules.
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S~lnl~ of the Invention
It has now been found that contact of metal surfaces, particular1y of galvani_edsteel or like ~h~ir~,o~ls surf~ces and of ~hlmimlm and its alloys that contain at least 45
% Of ~lllmimlm after any r,l.~ninf~ needed or desired but before autodeposition, with an
5 aqueous solution having a surface tension value at 30~ C not greater than 55 dynes per
cel-l;...tet~. and cons;s~ g çesenti~lly of, or pLGrGI~bly consisting of, water and:
(A) at least 0.008 %, based on the total solution, of a component of dissolved phos-
phcm~t~s, and, optionally, one or both of the following components:
(B) a coillpol1ent of dissolved surfactant, exclusive of phosphonates; and
10 (C) a component of dissolved non-o~itli7in~ mineral acid, exclusive of any material
that is part of colllpollent (A) or (B),
is exceptionally effective in re~ cing formation of pinholes or similar surface blçmiehes
after subsequent autodeposition. For purposes of this description, a "non-oxidi_ing min-
eral acid" is defined as in column 2 line 50 - 56 of U. S. Patent 4,477,390 of Oct. 16,1984
to Ledent et al., the entire srecific~tic n of which, except to the extent collLI~l y to any ex-
plicit st~tement herein, is hereby incorporated herein by IcrGlellce. Such metal ~IcL.Ga~-
ment compositions con~LiLuLe one embodiment of this invention. Another composition
embodiment ofthe invention is a con~ e from which a wulkhlg composition accord-
ing to the invention can be plt;paled by dilution with water.
In its ~ embodiment, a process accordillg to this invention comprises three
steps: (i) co..l~il;.~ a metal s~ ced object with a blemish inhibiting aqueous liquid pre-
coating composition as described above at a suitable t~nlpcl~LIlre for a sufficient time to
result in fewer b'-~iehes in a subse~ently autodeposited coating, this step being denoted
briefly as "blemish h~ g precoalil~ Ll~l...e~l" or "BIPT" and the aqueous liquid25 composition used being usually briefly denoted helein~ner as l'BIPTC"; (ii) removing
the metal sl~ ced object from contact with the BIPTC; and (iiij applying an autodeposit-
ed coating on the surface treated with the BIPTC in step ~i).
Detailed Description of Preferred Embodiments
The autodeposition composition and process themselves and tre~tmente with oth-
30 er compositions before the BIPT and after autodeposition, for example, cleaning the sub-
strate before contact with the BIPTC, simple and/or reactive rinses after autodeposition,
the use of chromium co,~ g or other known advantageous po~U~ nt composi-
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tions after autodeposition and rinsing, and heating or other processes such as steam treat-
ment to stabilize the initially formed coating film, are generally the same in an e~t~n~ed
process according to this invention as in the prior art. Specific prere. l ed conditions are
described in the wolking ex~mrles below.
~.erel~ly, a process according to this invention also incll-(les a rinse of the wet,
although drained, uncured coating formed in the autodeposition bath with one of the
aqueous compositions often known in the art as "reactive rinses", also known simply as
"rinses". Particularly plerellt;d reactive rinses are described in U. S. Patent 5,372,853
of Dec. 13, 1994 and in U. S. Application Serial No. 08/316,437 filed Sep. 30, 1994,
which, except to the extent that they may be inconsistent with any explicit st~tçm~nt
herein, are hereby inco,l,o,~led herein by reference. Other suitable reaction rinses are
described in the following U. S. Patents, the speçific~tion.e of all of which, except to the
extent that they may be inconeietçnt with any explicit st~tement herein, are hereby incor-
porated herein by ,c;r~lence: 5,432,694 of Aug.30, 1994; 5,428,525 of Sep. 30, 1993; and
5,164,234 of Nov. 17, 1992.
Any ~ ;"~ ofthe ~l~,irer~us s~lrf~ced object that is known to be needed or de-
sired before autodeposition coating in the prior autodeposition art may advantageously
be, and plefel~bly is, utilized in colln~ction with this invention before the blemish inhib-
iting precoating Lle~ l instead.
Under certain con~itione~ it may be advantageous to rinse with water a substratesurface treated with a BIPTC accoldii~ to the invention before introducing the substrate
into the autodeposition bath. Such rinsing is often unnecessary, however, and if not
needed is preferably avoided for economy.
Char~ct.qli.~tic co",~ol1ellL (A) of a colll~os;lion accordh,g to this invention prefer-
ably is selected from the group col1~;sLiilg of phosphonate ions that contain at least one
amino nitrogen atom, preferably a tertiary amino nitrogen atom, per ion. Independently,
the ions of this characteristic component (A) are preferably selected from ioms that con-
tain at least 2, or more preferably at least three, phosphonate moieties per ion. Also in-
dependently, when amino nitrogen is present, divalent hydrocarbon moieties selected
from the group of methylene and polymethylene moieties preferably connect the phos-
phorus atoms in each pho.cpl~ le moiety with an amino nitrogen atom; most pl~rel~bly,
these connecting moieties are methylene, with oligomers of methylene increasingly less
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plcrell~;d as the llullll~el of carbon atoms in these oligomers increases.
For convenience and econo,l,y, the ions of co",pollellL (A) are ~,ere,~bly addedto the BIPTC in the form of the commercially available corresponding phosphonic acids.
The single most plcrc~cd source for characteristic co".pollent (A) is diethylene triamine-
penta{methylene phosphonic acid} with the ~~hemic~l formula:
H~PO3CH2N~(CH~ (CH2PO~H~)2}2 and the second most p~erel,cd is aminotri~methyl-
ene phosphonic acid} with the chPmiC~l formula: N-(CH2PO3H2)3
The conccll~ ion of characteristic component (A) in the BIPTC can generally
vary over a wide range without ~rre~ P. the effectiveness of blemish inhibition very
strongly, particularly with the most effective inhibitors. For each particular molecular
type in component (A), there is ~ ecLed to be a "threshold" value below which little or
no inhibition will be achieved. In many cases, there is also expected to be a value, usual-
ly at least t~,vo orders of m~gnitllde above the threshold value, above which the blemish
inhibiting effectiveness of a particular molecular type decreases, perhaps because the
acidity becomes too high. Therefore, the technic~lly plcrel~le values of concellLl~Lion
of colllpoll~cllL (A) will depend in detail on the particular molecules used. In addition, the
practically pler;;l~'c value will depend on economics: If the rinse solution is not recycl-
ed, as is usually more convenient, it is pr~r~l ~le from the cost point of view to use as
little of the inhibiting additive as will be ~deq~l~tPly effective for the purpose.
Generally, from the viewpoint of obLail~ g nlOxilllulll inhibition of blemi~hç~ the
concentration of component (A) in a working precoat l~ composition according
to the invention preferably is, with incleasil~ pler~rence in the order given, at least
0.0085, 0.0088, 0.0091, 0.0094, 0.0097, or 0.0100, %, and for less preferable molecular
types more preferably is, with ill.ireasillg pltir~ ce in the order given, at least 0.020,
26 0.030, 0.040, or 0.080 %. Independently, for economic reasons, the concellLl~Lion of
component (A) in a working precoat tre~tm~ont composition according to the invention
preferably is, with increasing pre~lel,ce in the order given, not more than 50, 25, 10, 5,
3, 2, 1, 0.5, 0.3, 0.2, 0.10, 0.080, 0.060, or 0.050 % and for the most prere.,~d molecules
for ~Ill~on~ (A) more preferably is, with increasing p~ e~, ~.,ce in the order given, not
~ 30 more than 0.040, 0.020, or 0.015 %.
The concell~ ion of phosphonate was determined by titration of a 250 millilitçr
(hereinafter usually abbreviated "mL") sample of working composition with 0.025 N
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thorium nitrate solution, after ~c;~ifir~tiQn of the sample with a solution of 1 % nitric
acid in water to the extent l-ecç~s~ y to make the sample dear and light yellow in color
and then addition of 1 mL of a solution of 9.45 grams of monochloroacetic acid in a
mixture of 40 mL of 5 % NaOH solution in water and 60 mL of additional deionizedwater, using alizarin indicator, to the first salmon pink end point that persists for at least
30 seconds. Each mL of the titrant solution consumed co-lGspol1ds to 12.8 part per
million of phosphonates in the working composition.
In general, the p. crGllGd phosphonic acid sources of component (A) are commer-
cially available only in solution in con~ina~ion with non-oxidizing mineral acids that act
to stabilize the acids against cryst~ tion, as described in U. S. Patent 4,477,390 al-
ready cited above. Accordingly, compositions acco- .Ihlg to the invention normally pref-
erably contain optional component (C). The amount of component (C), when it is made
up of hydrochloric acid as is generally most p.Gre..ed, preferably is such that the ratio
of COIIIPO1IGIIL (C) to co...pol1ent (A), the latter measured as its stoichiometric equivalent
of corresponding phosphonic acids, is at least, with increasing plefelGllce in the order
given, 0.10. 0.15, 0.20, 0.25, 0.28, 0.30, or 0.32:1.0 and independently preferably is not
more than, with increasing p-Gre-G..ce in the order given, 1.0:1.0, 0.80:1.0, 0.70:1.0,
0.65:1.0, 0.60:1.0, 0.55:1.0, 0.50:1.0, 0.45:1.0, 0.40:1.0, 0.37:1.0, 0.35:1.0, orO.33:1Ø
In order to Illhx;lll;~e the probability for avoiding blçmi~hes, the surface tension
20 of the precoat Lle~ composition according to this invention preferably is, with in-
c~ lg prGrt;lence in the order given, not more than 50, 48, 46, 44, 42, 41, 40, 39, 38,
37,36,35, or 34 dynes per cGn~ Ler when measured at 30 ~C by the Whilmey slide (or
plate) method. For details ofthe measurement of surface tension, see A. Ati~m.con~ Phys-
ical Chemistry of Surfaces, 3rd Ed., (John Wlley & Sons, New York, 1976), p. 23 - 25
2~ and C. Weser, ~IMea~ulGlllGlll of Interfacial Tension and Surface Tension - General Re-
view for Practical Man", GITFachzeitschrift fur das Laboratorium, 24 (G-I-T Verlag
Ernst Giebeler, Darmstadt, Germany, 1980),642-648 and 734-742.
Component (A) generally has a slight surface tension red~l~ing effect on other-
wise pure water, but in order to achieve more preferable values of surface tension for a
30 wulking precoat l~efl~llç~ll composition accol-lhlg to the invention, additional surfactant
is generally pl Gr~llGd as a co---po~ of the BIPTC. Any surfactant that is (i) chemically
stable in con~inalion with component (A) and water, (ii) is effective in recluçing the sur-
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face tension, and (iii) does not have any adverse effect on the quality of the coating sub-
sequently formed by autodeposition may be used One group of surf~ct~nts that have
been found particularly suitable and are effective in economically small conce.,L.~Lions
are aromatic s~lfon~tes and their salts, particularly the disulfonated derivatives of dodec-
Y1diPhtnYI ether c~ ercially supplied by Dow Chemical Co, ~irll~ntl, ~ichig~n un-
der the names DOWFAX~M 2Al and 2A0 Solution Surf~ct~nt~ The plt;r~llt;d amounts
of any sll r~ c are those required to attain the p-~relled surface tension values stated
in detail herein For DOWFAXrM 2Al, which is normally most prerel.ed, the concentra-
tion in a wu~ g BrPTC p- t;re ~bly is, with increasing ,ol ~re ~nce in the order given, at
least 0 0003, 0 0006, 0 0009, 0.0012, 0.0015, 0.0018, 0.0021, 0.0024, 0.0027, 0.0030,
0 0032, or 0 0034 % and, primarily for reasons of economy, independently preferably is,
with ill~ a~ l~ p.ere.el~e in the order given, not greater than 0 05, 0.03, 0.010, 0.0070,
0 0050, or 0 0040 %
The time of contact b~Lween the metal substrate being treated and the BIPTC ac-
16 cording to this invention and the telllpel~Lu-e during this contact may vary within wide
lirnits G~ lly, with the p-t;r~ -t;d tre~tm~nt compositions, the contact time p-t;rt;-~bly
is, with ill;lGasillg p-ere-ence in the order given, at least 5, 10, 15, 25, 35, 45, 50, 55, or
60 seconds (he-ein~Ller usually abbreviated "sec") and indepen-l~ntly, primarily for rea-
sons of economy, preferably is, with increasing pl ~;rerence in the order given, not more
than 30, 15, 10, 5, 4, 3, 2, 1.7, 1.5, 1.3, or 1 1 mimltes (he.eind~ler usually abbreviated
"min") The L ~e~ 1 compositions acco- di..g to the invention generally are adequately
effective at normal ambient te-..l)e. ~Lures of 20 - 25 ~ C and for convenience and econo-
my are generally p,~;re ~bly used within such a te ..pe ~Lu-e range, although they may be
used at any telll~ U1'eb~LWeen their r. ~ h.g and boiling points
The autodeposition bath used for a process acco-ding to this invention prere-~bly
comprises, more preferably consists essenti~lly of, or still more preferably consists of
water and
(A') from 5 to 550, more preferably from 30 to 300, still more preferably from 40 to
120, and most l"~r~ly from 40 to 80, g/L of a stably dispersed organic coating
~ 30 resm;
(B') from about 0.4 to about 5, more preferably from 0.5 to 4.0, still more preferably
from 1 0 to 3 0, g/L of fluoride ions;
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(C') an amount ~"~r.": .. l to provide from about 0.010 to about 0.20, more pl~;r~l~bly
from 0.011 to 0.09, still more preferably from 0.012 to 0.045, ox~ in~ equival-
ents per liter of an oxi~ ing agent s~lected from the group co~ of dichrom-
ate, hydrogen peroxide, ferric ions, and mixtures thereof; and
(D') a source of hydrogen ions in an amount sufficient to impart to the autodeposition
composition a pH in the range from 1.6 to 3.8, more preferably from 1.7 to 3.0,
still more "~rt;-~ly from 1.8 to 2.5.
One plert;..ed type of coating resin for use in forming autodeposited coatings in
a process acco- lhl~, to the present invention comprises internally stabilized vinylidene
chloride copolymers or externally stabilized vinylidene chloride copolymers co~ -g
in excess of 50 %, or more preferably at least 80 %, of residues from polymerizing vi-
nylidene chloride. Most prer~.~bly, the vinylidene chloride copolymer is crystalline in
nature. F~emrl~ry crystalline resins are described in U.S. Patents 3,922,451 and 3,617,
368, the disclosures of which, except for any part that may be incon.cictent with any ex-
plicit st~t~m~nt herein, are hereby incorporated herein by reference. Generally, crystal-
line poly(vinylidene chloride) co.~ np~ resins comprise a relatively high proportion of
residues from vinylidene chloride, for example, at least about 80 % by weight thereof.
A second plt;relled type of resin for use in autodeposition coating in connection
with this invention is an acrylic type, particularly copolymers of acrylonitrile. Further
details are given in U. S. Patent 4,313,861 of Feb. 2, 1982 to Bassett et al., the disclosure
of which, except for any part that may be h~c~ ent with any explicit statem~.nt herein,
is hereby incorporated herein by rere. el1ce.
The working BIPTC's may be conveniently p-epaled on site where used by dilut-
ing concentrates with water, and such concentrates are also within the scope of this in-
vention. Co"cc"l,~es nollllally plt;rel~bly contain from 3 to 20 times the concentrations
of components (A), (B), and (C) as described above for wo~king compositions.
The practice of the invention, especially in its preferred embodiments, may be
further appreciated from the following non-limiting examples and comparison examples.
Group 1
~eneral Expe~ lal Procedure
The process sequence used for this group of examples is shown in Table 1-1 be-
low. (Note: All products identified herein by the trademarks PARCO~, RIDOLINE~,
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Table 1-1
PROCESSING STEPS USED, GROUP 1
Process Step ~'luid Used Fluid Temper- Contact
ature, ~C Time,
Min
Spray ~ 72 g/L of PCL lS30A' 49 1 0
Dip Clean 144 g/L of PCL 1530A' in 60 2.0
water
Dip Rinse < 10 g/L of PCL 1530AI 2 in 20 - 25 1 0
water
Dip BIPTC See Table 2 20 - 25 1.0
Dip Rinse DI water 20 - 25 1.0
Dip A ~a r~ 6 - 7 % solids; see detailed 20 - 25 See Note3
el~. h~
Dwe.l Ambient air 20 - 2S 0.25
Dip Rinse Solutionmadebymixing49.6 20-25
parts of CoCO3,330 3 parts of
a solution in water of 20 %
nuù~..w ..c acid and 2.1 %
HF, and 638.5 parts of DI
water4
Cure Hot air 88 20
General Notes for Table 1-1
"PCL" is an abb.~,~iatiol. for "PARCO(~) Cleaner". PCL 1530A, with or without added PCL lS30S
(see footnote 1 below), is a w~ iunal ~u~ ~ly strong a.kaline cleamer with - fi
Footnotes for Table 1-1
'If .,ub.,l.alt;s were not free from water brealcs when using PARCO~) Cleaner 1530A alone, 2 g/L
of PARCO~) Cleaner lS30S were also dissolved i.-. the spray ".c; -le~ g and dip cleaning f.uids
2No PCL 1530A or S was de.iberately added to this f.uid, but because of drag-out from the preced-
ing stage, it may have c~ ~1 as much as 10 g/L
3The i~u~ .,ioll time, along with the solids cu~ Lalion of the ~nth~e~.~ g cu.-.,~silion (within
the 6 - 7 % range ~pe~ifiçd)~ was adjusted to produce a d.-y ~lltod~ d coating thirl~n~s$ of 17 8
+ 2 5 mic.u.l.- k; ~
4The solute in this solution is believed to consist ".~ ;. ~ y of cobalt nuu~ u..alt; after mixing
and evolution of gas, ,vl~ u...dl)ly carbon dioxide, which occurs after mixing. The solution was
replaced after every 100 panels ,,.uccssel
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and AUTOPHORETIC~, togethP,r with detailed directions for using them as described
below, are col-lme~ dlly available from the Parker ~mrhPm Div. of Henkel Corp., Madi-
son Heights, Michig~n ) The precoat Ll~ l bath compositions are shown in Table
1-2 below.
Ple~ ion of 18.5 liters (helein~ler usually abbreviated "L") of a "normal acti-
vation" autodeposition bath was accomplished as follows: Into an adequate size high
density polyethylene (helein~flel usually abbreviated as " HDPE") colll~illGl for the final
mixture were added 3.37 kilograms (helehl~Qer usually abbreviated "kg") of AUTO-PHORETIC~ 866 Replenisher (hereinafter usually abbreviated "866 Replenisher" or
simply "866"), which cont~inc 37.5 % solids, and 12.1 kg of industrially deionized (here-
inafcer usually abbreviated "DI") water. To this first mixture, a sepal~ely mixed solution
of 0.99 kg of AUTOPHORETIC~ Starter 300 (helGill~lGl usually abbreviated as "Starter
300" or "S 300") and 2.96 kg of DI water was then slowly added with consL~ll stirring,
using a motor driven stirrer. ~ltlition of the starter solution to the solution of 866 took
approkimalely 20 mimltçs S-lfficiP-nt hydrofiuoric acid was then added to result in a
reading of 248 micro~llpelGs (heleil,~ne, usually abbreviated ",uA") on a LINE-
GUARD~) 101 fluoride activity meter (helGinaner usually abbreviated "101 Meter").
This composition had an o~ tit~n-reduction potential (he,einaner usually abbreviated
"ORP") value for a smooth platinum electrode immersed in the composition, co"lpalGd
to a standard hydrogen electrode, of 375 l 25 millivolts (herGill~le, usually abbreviated
"mv")
P~Gpa,~lion of a "low activation" autodeposition bath was pG,~"lled ;dentic~lly
to the "normal activation" bath, except for using the following amounts of materials:
3.37 kg of 866 P~ q~F' -.nich~.r with 9.24 kg of DI water; 0.70 kg of Starter 300 diluted with
3.12 kg of DI water; and a reading of 110,uA on the 101 Meter. The ORP was the same
as for the "normal activation" bath The coating resin in both these examples of autodep-
osition baths is a crystalline copolymer of vinylidene chloride~
During use, autodeposition baths were ...A;..~ ed between 6 - 7 % of total solids
by the addition of 866 Replenisher as needed to compensate for the loss of coating resin
30 from the baths, primarily by transfer of the resin into the autodeposited coatings formed
during use. AUTOPHORETIC~ Oxidizer 24 was added to ~"~ the ORP range
specified aboveforeachbath, and hydrofluoricacidwasaddedto ",~;"~ , 101 Meter
~ 10
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Table 1-2
PRECOAT TREATMENT BATH COMPOSITIONS, GROUP 1
PRECOATACTIVE INGREDIENT
DESIGNATION INGREDIENT(S) CONOENTRATION
D2060 A DequestTM 2060 0 01 % Active
DowfaxTM 2A 10 0031 Wt-Vol % Active
D2060 B DequestTM 2060 0 02 % Active
DowfaxTM 2A 10 0031 Wt Vol % Active
D2060 C DequestTM 2060 0 04 % Active
DowfaxTM 2A1 0 0031 Wt-Vol % Active
D2000 A DequestTM 2000 0 01 % Active
DowfaxTM 2A 10 0031 Wt-Vol % Active
D2000 B DequestTM 2000 0 02 % Active
DowfaxTM 2A 10 0031 Wt-Vol % Active
D2000 C DequestTM2000 0 04 %Active
DowfaxTM 2A1 0 0031 Wt-Vol % Active
D2060/2A0 DequestTM2060 0 04 %Active
DowfaxTM 2A0 0 0031 Wt-Vol % Active
H3PO4 A H3PO4 0 20 Molar
H3PO4B H3PO4 0.40 Molar
H3PO4 C H3PO4 0.80 Molar
HF + H2~2 HF 0.0011 % Active
H2~2 1 0 % Active
DI DI Water
Notes for Table 1-2
Precoat Decign~tion DI and all other Precoat Desi~n~tionc not beginning with the letter "D" are
colll~allson examples, not accol.lillg to the invention
"Wt-Vol %" means that the volume of the liquid solution in which the DOWFAXTM .,ulra~;~ll~,
are supplied was Ill~a~ d directly, then the volume percent coll~i",olldillg to this volume in
respect to the volume of the entire cwll~osilion was multiplied by the weight percent of
ph~ .hr,l~ic acid(s) in the liquid solution to obtain the "Wt Vol % "
11
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re~lin~e of 250+25 ~lA in the "normal activation" ~he,t;;l,~ler usually abbreviated as
"NA") autodeposition bath and 110+10 ~lA in the "low activation" (hereil1~ler usually
abbreviated as "LA") bath. A separate BIPTC was used for each type (i.e., NA or LA)
of autodeposition bath.
Allmetalsul~ lesprocessedwerele~ rpanels 10.16x 15.24cç.~1i.. le
i.~lel usually abbreviated "cm") in size; these were prepaled by bieecting rect~n~
lar panels 10.16 x 30.48 cm in size supplied by ACT Laboratories, Inc., ~illc-l~le7 Michi-
gan. Three types of metal were used: Cold Rolled Steel (hereinafter usually abbreviated
"CRS"), Code APR 11721, 6.6 millimeters (hereill~[ler usually abbreviated "mm") thick,
clean, unpolished, Batch 30425414 or 31021314; Hot-dipped Galvanized Steel (he~t;illar-
ter usually abbreviated "G60"), Code APR 10260, 8.9 mm thick; and Galv~nn~led Steel
(herei"~ler usually abbreviated "A60"), Code APR 16966, 7.6 mm thick, clean, unpol-
ished, Batch 20622416 or 20315416. Panels were dipped two at a time, using two hooks
att~-h~.d to the same ~U~pOl L~l~ rod, for the process sequence. A total of 18 panels were
processed for each BIPTC: six of CRS, six of G60 and six of A60.
Physical testing included GM 951 lP, 20-cycle, scribe/scab, 504-hour salt spray
(ASTM B117-90), impact (ASTM 2794-87, except that no evaluation ofthe pattern ofcoating removed by the tape was made), and initial adhesion (ASTM D3359-87) testing.
Table 1-3 lists observations of the presence of pinholing/blistering on the initially
oven cured coated panels as well as impact, GM 951 lP, 20-cycle scribe/scab, salt spray
and initial adhesion results. Coatings having ~ignific~nt blistering and/or pinholing after
oven cure were not tested further.
The following conclusions were drawn from the results shown in Table 1-3:
The expe~ l BIPTC's found to give the best overall l~e,ro"~ ce were those
Col,l;~ DEQUESTrM 2060. Conce~ lions of at least 0.02 % of this material (which
contains only about 50 % of its active phosphonic acid ingredient) appeared to give the
best overall results under both low and normal activation conditions for the autodeposi-
tion bath. G60, A60 and CRS panels were all pinhole and blister-free after oven cure.
Initial adhesion was not affected by the precoat tre~tment step when coll,pared to a DI
co~ cuisoll precoat Ll~llllt;lll step, but corrosion results after subsequent autodeposition
coating were s~l~,lially better with a ll~llllelll composition according to the invention.
Differences in salt spray and scribe/scab pe~ro~lllallce results between low and normal
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Table1-3
STEEL AND ZINC-AILOY ST EL COATING PROCESS RESULTS, GROUP 1
t
PrecoatBathlPinhol- Iniffal Im-S04 Hr SS Scribe/
Desig- Panelin~lBli~- Adhe- pact Scab
natlon Typestering rion Creep, Mm
LA/G60 None 5B 690-4~35 o 355 1,1
D2A060LA/A60 None >4B 690-495, 0 495 1,1
LA/CRS None >4B 115o-12S, 1-2 2,2
LA/G60 None SB 462-345, 0-3 ~os I, I
D2B060LA/A60 None 5B 460-12sVF6 0-145 1,1
LA/CRS None >4B 1610-2, 0-2 4,3
LA/G60 None 5B 231-265,1-2'55 1,1
D2060
C LA/A60 None >4B 690-125 VF8, 0 31os 1,1
VF2
LA/CRS None >4B 69 1-1,1-1'5 2,2
LA/G60 None SB 23~-355,1-355 1,1
D2A000LA/A60 None IB <230-25 VF5, 0-2 VF5 1,1
LA/CRS None >4B 1841-1, 1_125 3,3
LA/G60 None SB 460-2JS F6, 0-2JS F6 1, I
D2000
B WA60 None IB 230-3'5, 0-2"5 1,1
LA/CRS None >4B 1380-125, 0-1 2,2
LA/G60 None SB 23o-48S VF6, 0-3"5 1,1
D2000
C LA/A60 None >4B <46o-235 VF6, 0-125 VF6 1,1
LA/CRS None >4B 138 1-1,1-1 2,2
H3PO4LA/G60Vely Few 2B <230-355 VF6, 0-235 so/OpI ~ I
A Pinholes
LA/A60Medium - - - -
Pinholes
LA/CRSVeryfew >4B 1840 l2s 0 1 2,3
blisters
...Table continued on next page ...
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Precoat Batb~Pinhol- Initiai Im-504 HrSS Scribe/
Desig- Paneling/Bli~- Adhe- pact Scab
nation Typestering don Creep, Mm
H,PO4 WG60 Few 3-4B <230-235 FM4, 0-255 2,2
B pinholes FM6
WA60 Medium - - -
pinholes
WCRS Veryfew >4B 1840-1, 0-125 2,2
pinholes
H3PO4 WG60Very few 3B <230-245, 0-345 1,1
C blisters
WA60 Medium
pinholes
LA/CRSVeryfew >4B 1840-125, 0-125 2,2
blisters
HF + WG60 None SB <461-365 VF8, 0-2'5 VF6 1,1
H2O2 WA60 Pinholes
WCRS None >4B 1841-1, 0-1 2,2
DI LA/G60 None SB 1613-11 5%P, 0-35sF6 1,1
LA/A60 None 2B <230-355 VF6, 0-14sF6 1,1
LA/CRS None >4B 1841-1,1-1 1,2
Com. A NA/CRS None SB <231-2,1-2 F9 2,2, 2,2
Com. B - None SB <23N, 0-15 3,3, 2,3
D2060 NA/G60 None >4B <230-3~C5 50/oP, o 4ss1, <I
NA/A60 None >4B 460-25sF8, o-24sF2 ~1, 1
NA/CRS None >4B 461-2, 1-2 2, 2
D2060 NA/G60 None >4B <230-4 VF6, 0-345 5%P<1, 'I
NA/A60 None >4B <23o-25S VF8, 0-25 VF8<1, <I
NA/CRS None >4B 46 1-1,1-2 2,2
D2060 NA/G60 None >4B <230-245 VF8,0-4~ VF6 <1, 1
NA/A60 None >4B <230-25 VF8, 0-25 VF8 <1, 1
NA/CRS None >4B 231-I, 1-I 2,2
D2000 NA/G60 None >4B ~230-3gS VF4, 1-4 VF6 1,1
NA/A60Vely few 2B <230-2 F8, 0-235 F8 1, I
blisters
NA/CRS None >4B <231-2,1-2 3,2
...Table continued on next page ...
14
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Precoat BYth/Pinhol~ Uial Im- S04 Hr SS Scribe/
Dcsig- P~nelingtBlis- Adhe- p~lCt Scab
nation TypeJtering sion Creep~ Mm
D2000B NA/G60 None SB c23 0-4'~sF6, 1-3VF8 <1,1
NA/A60 Very few 2B <23 0-45 F8, 0-45 F6 1, I
blisters
NA/CRS None ~4B <46 I l2s l l2s 2,2
D2000 C NA/G60 None >4B <23 1 -4~5 F6, 1 -455 F6 1, I
NA/A60 F~,..M~i. 4B c23 0-3sVF8,0-lsVF8 <I,cl
pinholes
NA/CRS None 5B 69 1-2, 1-2 2,3
H3PO~A NA/G60 Veryfew IB ~23 0-26sF6,0-46sF6 1,1 (VF9,
pinholes VF9)
NA/A60 Mediu~n
pinholes
NA/CRS None >4B 46 1-125, 1-125 1,1
H3PO4 B NA/G60 Very few I B c23 0-3 F6, o-365 F6 1, I (VFg, VFg)
pinholes
NA/A60 Medium
~J".1...1;i-~
NA/CRS None >4B 46 1-2, 1-2 2,3
H3PO4C NA/G60 Veryfew IB <23 o 35sF6~o-3F6 1,1 (VF8,VF8)
pinholes
NA/A60 Medium
olil~g
NA/CRS None >4B 46 1 I I 1 2S 4,2
HF+ NA/G60 Few- 3-4B <~!3 1-235, 1-2 1,1 (FM8,
H2O2 medium FM8)
pinholes
NA/A60 Medium
oL~g
few blisters
NA/CRS None SB 46 1-2, 1-235 2,2
DI NA/G60 Few 3B <23 1 365F6,1-3F4 1,I
piIlholes
NA/A60 Medium IB <23
pinholes
few blisters
NA/CRS None >4B c69 1-2, 1-2 2,2
...Table conhnued on next page ...
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Precoat B~th/ Pinhol-InUial Im- S04 HrSS Scribe/
De~ig- P~neling/Blis-Adhe- pact Scab
nation Types tering ~ion Creep, Mm
D2060/ NA/G60 None >4B '23 o-36S, 0-2'~S <1,1
2A0 NA/A60 None >4B <23 0-45 F8, 0-25 F8 1,1
NA/CRS None >4B >23 1 -2,1 - I 2,2
N- t~ for Table 1-3
"Comp. A" is a ~ ;co" example in which no precoat L~ was used and the rinse after
autoJ~ ition was an aqueous solution of n~ dtt;~ but other process steps were the
same as for "normal activation" autodeposition acc~l~li-lg to the invention.
"Comp. B" is a culll~ example in which the metal ~ul.~l-..Le was coated with an ~ d.,~os-
ited paint (I~u..~ unTM 500) that is generally ~ù ~id~,.~ very high in quality, instead of any auto-
deposited coating.
activation baths were not signific~nt
Coatings after DEQIlESTIM 2000 C.J..~ g pl~ nl ~~-P.nt compositions had com-
parable salt spray and scribe/scab p~lrulll~lce to those after DEQUESI~M 2060. Howev-
er, DEQUESI~M 2000 COI~IA;~ Ig precoat 11'eAI~ ; were less effective at pinhole pre-
5 vention over galv~nne~led A60 panels under "normal activation" bath conditions (101
Meter reading = 250 ,uA), and appeared to require at least twice as high a concentration
as with DEQUEST~ 2060 co..l ~ compo~ilions to provide the most corrosion resist-ance on the more ~lifficl-lt to protect galv~nnP~lPd substrates.
H3PO4 co~ g con~itinning rinses were unable to produce pinhole-free co~tings
over galvannealed A60 steel at all precoat conce.. l.~lions and ACC-866 bath activation
levels tested. Salt spray and scribe/scab pelru~ allce results were slightly lower than for
the DEQUESTTM arninophosphonic acid c~-."~ g BIPTC's.
H~ - H2O2 nlixl~llts were not effective in çl;,~ g pinholes and blisters on gal-v~nne~led steel.
Salt spray (ASTM B117-90) tests resulted in some field blistering and cathodic de-
l~min~tion spots on both G60 and A60 panels for all precoat conditioning rinses tried
here. Such results are always or almost always observed during this type of testing of
samples with ~.ncire.olls surfaces, even when these surfaces are protected with coatings
known to give çxcP.llP.nt corrosion l~ .e under practical use conditions. However, the
precoat contlitioning rinses do appear to reduce the severity of the salt spray in~lced field
blislelillg and dPl~min~finn, which are much less severe for A60 panels than for G60 pan-
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.}
els in general.
GM 951 lP, 20-cycle scribe/scab data were excellent for all DEQUESTTM amino-
pho~ ~h --- acid co.~ BIPTC's and both ACC-866 bath activation levels tried. Typi-
cal creep widths for all A60 and G60 panels were 1 mm or less in total creep. Total creep
5 widths over CRS were typically 2 mm, comp~ble to those now achieved with the best
prior art autodeposition teçhnolQgy, in(1ie~ting that autodeposition coatings applied after
a BIPT accc Idil,g to the invention are at least as s~ti.~f~ctory as other autodeposition coat-
ings on CRS and therefore may be used on composite objects co~ il-il-g both CRS and
z inc coated ~rf~s without deterioration of the best pel r~,llllance now achieved by auto-
10 deposition coating of CRS alone.
Impact test results were somewhat erratic as is normal for autodeposition coatedCRS ~ubsll~les~ but there is no evidence that the aminophosphonic acid CO..~ g BIPT
nifc~ntly afffects impact test pe.rollllance either adversely or positively.
Group 2
A major objective of this group of examples was to establish consumption levels
ofthe BIPTC active i.l~enl~ during prolonged use. Unless otherwise stated below, op-
erating conditions were the sarne as for Group 1.
General Conditions of Operation
In plGIJalillg the a llode~o~lion baths, 0.94 rather than 0.99 kg of AUTOPHORET-IC~ Starter 300 and 2.45 kg instead of 2.96 kg of water were used. The 101 Meterfluoride sensing reading was 150 instead of 240 ~lamps.
A BIPTC concentrate was pl~aled as follows: In an adequate size HDPE jug
were mixed 54.00~0.01 g of Dequest 2060, 4.41 ~0.01 g of Dowfax 2Al and sufficient
DI water to produce a total conc~ e mass of 3000+ 1 g. To prepare a WOlhillg BIPTC,
150.0+0.1 g ofthe ~l~n~.l;oned BIPTC co~ le was then diluted to 3000~ 1 g with
DI water and stirred. 1300 l l g of this solution was added to a narrow stainless steel
panel coating tank designed to accommodate the rect~n~ r test panels, which were 10
by 30 cm in size, with minim~l solution volume.
Phosphonate concentrations in the working BIPTC's were monitored and main-
tained at intervals after use of the BIPTC by removing a 250 11 g sample of the BIPTC
(while no substrates were being processed) and titrating this sample with a thorium nitrate
solution as already described above. The l~ ;llg 1050~1 g of the used working
17
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BIPTC was then mixed with an amount of the BIPTC conce~ e described above that
was calc~ ted, based on the results of the titrated sample, to result in a mixture having
the origirial phosphonate conce~ lion ofthe working BIPTC in a total mass of 1550+ 1
g ofthe mixture, and sllfficient DI water to bring the total mass ofthis mixture to 1550 l 3
1 g was then added and well mixed. A second 250+ 1 g sample was then taken from this
mixture and titrated as described above, to d~Lel ll~ine whelllel the col-ce~ Lion of phos-
phon~te in the mixture had been restored to at least the value originally present in the
freshly made BIPTC. If it had, the r~ 1300+1 g ofthe mixture was usually con-
tinued in use as l~r ' ~ used BIPTC to pretreat more substrate panels, as noted in spe-
cific in~t~nces below.
The general process sequence used for this group is shown in Table 2-1 below.
The substrate materials used, with the abbreviations for them used in the following de-
s~ription shown within quotation marks in par~ .es;~ after each substrate type name be-
low, were as follows:
Cold Rolled Steel ("CRS"), Code APR 11721, 6.6 mm thick, clean, unpolished, Batch
31216414.
Hot-dipped Galvanized ("G60"), Code APR 10260, 8.9 mm thick, clean, unpolished,
Batch 20109516.
Galv~nne~led ("A60"), Code APR 16966, 7.6 mm thick, clean, unpolished, Batch
31004416.
Hot-dipped Galvanized/Cold Rolled Steel, Bimet~llic, end-to-end lap joint ("G60/CRS"),
Code 10270, Batch 21214416, Panel A: ACTCRS, Panel B: ACT G60.
Galvannealed/Cold Rolled Steel, Bimet~llic, end-to-end lap joint ("A60/CRS"), Code
10270, Batch 21214416, Panel A: ACTCRS, Panel B: ACT A60.
Cured coating ~peal~ce data as a function of substrate and use or non-use of theacid cleaning and subsequent rinse steps are shown in Table 2-2 below. "Comparison I"
in this table was a commercial product, AUTOPHORETIC~ Conditioning Rinse 3180.
Panels in this processing sequence were processed one at a time, with the sub-
strates being processed in the following sequence: First, six each of G60/CRS and A60/
CRS type panels were processed in alternating sequence. Secondly, nine CRS, nine A60
and nine G60 panels were processed, one of each type being processed before a second
one of any type was processed, etc. Thirdly, six G60/CRS and six A60/CRS panels were
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Table 2-1
PROCESSING STEPS USED IN GROUP 2
Process Step Fluid Used Fluid Temper- Colltact
ature,~C Time,
Min
Spray ~ Clean 60 g/L of RDL 1007 77 2.0
Dip Rinse Tap water 20 - 25 1.0
Dip Acid Cleanl2 % by volume of AC 7150 66 1.0
Dip Rinsel Tap water 20 - 2S 1.0
Dip BIPTC See Table 2-2 20 - 2S 1.0
Dip Rinse DI water 20 - 25 1.0
Dip ~ ' I r 6 - 7 % solids; see detailed 20 - 25 See Note2
C~J~ ~ cl~... G
Dip Rinse Tap water 20 - 25 1.0
Dip Rinse Solution made by mixing 49.6 20 - 25 1.0
parts of CoCO3, 330.3 parts of
a solution in water of 20 %
lluo~ilwluc acid and 2.1 % HF,
and 638.5 parts of DI water3
Cure Hot air 110 30
General Notes for Table 2-1
"RDL" is an ~l,.ciYi~ion for "RlDOLrNE~) Cleaner"; RDL 1007 is a solid, puvvd~ ,d, ~ t~l
strongly alkaline cleaner cullce~ ..t~. "AC 7150" is an ~I-eY;aljO - for AUTOPHORETIC(~9 7150
Acid Cleaner, a liquid C~ GIIh ~ for ~ ~i..g a spray cleaning solution APC;gl1~d to remove light
rust and r~Yi~l~ti~n from oil- and grease-free iron and steel surfaces before applying an ~nto~
coating.
Footnotes for Table 2-1
IThis step was used only on ~ .~;. that included some wld rolled steel, and not on all such
su~ dlG~, ~ r~ c are noted in the following tables.
2The immersion time, along with the solids COII~II1d~iUII of the ~lto~ x~ g c~ n~ ion (within
the 6 - 7 % range sperified), was adjusted to produce a dry autodGposiLtd wating ~ LIIeCC of 25.4
+ 2.5 ~lliGl~UUGI~
3The solute in this solution is believed to consist ~ ly of cobalt fluu~uwlldlG after mixing
and Gvululiull of gas, IJ-G~u uably carbon dioxide, which occurs after mixing.
19
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TABLE2-2
Sub~ g Rin~ing C~
~tr~te
Type ,~ ~ gtotheIh.~ '- C~, ~ I DIW~ter
With Acld Clean No Acid Cle~m
CRSNo blistering and/orNo blistering and/or Blistering and/orBlistering and/or
,~.. "llolillg ~,illl.olillg pinholing pinholin~
G60No hli~ing and/orNo blistering and/or Trace of ~.;.. l~f~l;.l~ Slight to moderate
~ lhollllg ~ blistering at edges
A60Tracepinholing,trace Trace~.;... 1.,-1;.. ~ trace Severe~,...... ,lloLIg Severepish~olirlg
blistering blistering and blistering and blistering
G60/ Trace ~.;l~nl;~ in spots Trace ~ in spots Coating missing in Coating missing in
CRSat joint interface. Coating at joint interface. spots near joint spots near joint
missing in spots near joint inte~face. Rlict~rin~ interface
interface. and pinholing at lap
joint and welds.
A60/ Coating missing in spot~,Trace blict~in~ alongDen~,e to severe ---
CRSnear joint interface. Trace joint interface edges.blistering on A60
rinhr~lin~ on A60 panel Trace l.;.. h- I;... g on A60 panel half.
half. panel half. Rli~t~rin~ at
interface joint.
again processed in allel-~Lillg sequence. Fourthly, another eleven each of CRS, A60, and
G60 panels were processed in the same sequence as before, followed by three each of
G60/CRS and A60/CRS panels in ~ I ;Ol~ with each other. Finally, various control and
other test panels were processed as needed.
Table 2-3 shows data relevant to the co~ ;on of phosphonate during a process
accc,ld;ng to the invention. The average con,ulnplion calculated from the values in Table
2-3 is 7.6 g of the BITC concentrate per square meter of substrate surface processed.
The working BIPTC was analyzed for various el~ment~ at the beginning and end
of use as described above. Results are shown in Table 2-4. They indicate that zinc is the
primary metal dissolved from the substrates during BIPT of galvanized steel according
to the invention and that the phosphonate active ingredient is converted to some other sol-
uble phosphorus cont~ining compound, at least part of which remains in solution in the
BIPTC.
Physical testing results for Group 2 are shown in Tables 2-5, 2-6, and 2-7 below.
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TABLE 2-3
Square Titration O~re.~ ~ ~~ and D~ Actions
Meters of ~ ~ t,
Substrate mL of 0.025
~r.,ce~s~d ArThorium
per Liter of Mtrate
BIPI C Solution
o 10.2 . Titration value for freshly made unused working BIPTC
1.19 6.5 . Pillllolillg increase ol~ ~ on A60 panel coated.
. Added BIPTC co~ lLI~t~, to bring to 10.3 ml titration
for the working collll,o~;Lioll, and c~ ~ S';-'.
3.09 - . Observed coating w~hoffin areas on G60 panel during tap
water rinse after ~.. lod~,~osilion step.
. Added 130 mL of ~ viou~l~/ unused working BIPTC and
.u~d p~
3.38 5.3 . Observed .~ ~lo(~ o~it~ coating washoffin areas during tap
water rinse step.
. Adjusted c~ m with BIPTC c..ll~..L.~te to 10.6 ml
titration value for the working cc,l..~o~ilion and c~
5.46 3.8 . Autodci~,o~iled coating washoff in areas obs~ d on G60
panel.
. Adjusted col~c~,l-L.~.~ion with BIPTC C~ lale to 11.7 ml
titration value for the working c~ )o~ilion. C~ i until
a total of 5.85 square meters per liter had been ~l~S .~l.
The results of Group 2 led to the follovving conclusions:
The D2060/2A1 type BIPTC gave superior coating panel appearance compared
s to the best previous commercial BIPTC, AUTOPHORETIC~) 3180 Conditioning Rinse.Tre~ ..l accolding to the invention described herein gave co~ting~ with no blistering
and/or pinhr~ling over CRS and G60 ~ul~sll~le~ and only trace pinholing over A60 galvan-
nealed steel was observed.
F.limin~tion of the 7150 acid cleaning step improves coating coverage over a zinc
10 coated steel-to-steel lap joint region with the best example of a BIPT according to the in-
vention.
- The initial consumption rate of active ingredient from the BIPTC was calculated
to be 39.8 g of phrsphon~te per 1000 m2 of substrate processed. Consumption rate dimin-
ished to a~p~ alely 23.7 g of phosphonate per 1000 m2 between 3.4 and 5.5 m2 of
21
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TABLE 2-4
Element Concentration of Element in the BIPTC
For Before UseAfter r~ ocessing 5.85 m2/L
Fe C 1 ppm 4 ppm
Zn <lppm 0.16%
Si < 1 ppm 4 ppm
Al < 1 ppm < 1 ppm
P 0.013 % 0.12 %
Abbreviations for Table 2-4
"ppm" = "parts per million"; "m2/L" = square meters of substrate per liter of BIPTC.
TABLE 2-5
Substrate M2~ Initial ~(ll: ~r Values T~p-~t Test Values
Previously
Treatedl Zn Coated CRS Lap Joint Zn Coated CRS
Portion Portion Interface Portion Portion
A60/CRS 0.24 >4B >4B 4B >40 >160
A60 1.34 >4B >140
A60 1.90 >4B >120
A60/CRS 2.37 >4B >4B >4B 120 >160
A60 3.80 >4B >120
A60/CRS 4.51 >4B >4B 4B >120 >160
A60 5.24 4B >120
A60/CRS2 5.71 3-4B 4B 3-4B >80 >160
G60/CRS 0.29 >4B >4B 4B >80 >160
G60 1.38 >4B >140
G60 1.81 >4B 120
...Table cont~nued on next page ...
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Substrate M2/LInitial Adhesion Values Impact Test V~lues
Previously
Treated' Zn Coated CRS L~p Joint Zn Coated CRS
Portion Portion Interface Portion Portion
G60/CRS 2.43 >4B >4B >4B >120 >160
G60 3.85 >4B >100
G60 4.56 >4B >4B 2B >120 >160
G60/CRS2 4 66 >4B >4B 4B >100 >160
G60/CRS2 5.27 4B >20
G60/CRS -3 >4B >4B 4B >100 >160
G60 -3 4B >100
G60/CRS -4 4B >4B 3~B >80 > 160
CRS 1.28 >4B >160
CRS 1.85 >4B >160
CRS 3.75 >4B >160
CRS2 5.19 4B >160
CRS -3 4B > 160
CRS -4 >4B >160
CRS -5 >4B >160
CRS _6 >4B <20
Footnotes for Table 2-5
'With the same batch of BIPTC, except for repleni~hm~nt 2The acid çle~ning step and immedi-
ately following rinse step were omitted for this substrate in this in~t~nce. 3Comparison example
with AUTOPHORETIC~) Conditioning Rinse 3180 rather than a BIPT according to this inven-
tion. 4Co...~ ;con PY~mrle with no BIPT other than rinsing with DI water. 5Comparison examp-
le with no BIPT and with a di~t;lelll reactive rinse, AUTOPHORETIC~ Reaction Rinse 2150.
6Comparison example with electrophoretic paint coating rather than autodeposited coating.
substrate processed per liter of starting BIPTC. This may be due to build up of soluble
metal phosphonate byproducts in the used BIPTC.
A miniml-m con~ lion of about 83 ppm of phosphonate in the BIPTC is neces-
sary for cured co~tingc to have the best appearance obtained. The nature of the failure or
defects depended on the amount of substrate processed through the precoat bath. Lower
CA 02230278 1998-02-24
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TABLE2-6
Substrate M2/LP~ c- ~ Scribe-Scab TestResult, mm
Treatedl Zn Coated Portion CRS Portion
A60/CRS 0.14 <1, F-M9 3, Field ~st
A60/CRS 0.33 <1, F-M9 2, Field ~st
A60 0.76 <1, F-M9
A60 1.05 <1, F-M8
A60/CRS 2.09 1, F-M9 2, Field ~st
A60/CRS 2.28 1, F-M9 2, Field ~st
A60 2.62 l,F-M8
A60 2.92 1, F-M9
A60 3.68 <1, F-M'
A60 3.94 l,F-M6
A60/CRS 4.34 <l,F-M8 2, Field ~st
A60/CRS 4.43 l,F-M8 2, Field ~st
A60/CRS2 4.61 1, F-M9 2, Field ~st
G60/CRS 0.19 <1, F-M9 2, Field ~st
G60/CRS 0.58 <1, F-M9 2, Field ~st
G60 0.81 <l,F-M8
G60 1.10 1, F-M9
G60/CRS 2.14 <l,F-M8 2, Field ~st
G60/CRS 2.33 <l,F-M8 2, Field ~st
G60 2.67 <l,F-M8
G60 2.96 <l,F-M8
G60 3 .58 1, F-M4
G60 3.99 <1, F-M6 2, Field rust
G60/CRS 4.29 <1, F-M9 2, Field ~st
...Table contfnued on next page ...
24
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W O 97/09127 PCT~US96/13480
SubstrateM~ G- C ~IY S~--' Z Scab Test Result, mm
Treatedl Zn Coated Portion CRS Portion
G60/CRS 4.39 <1, F-M9 2, Field rust
G60/CRS 4.70 <1, F-M9 2, Field rust
~ G60/CRS 4.75 <1, F-M9 2, Field rust
G60/CRS -3 <1, F-M9 2, Field rust
G60/CRS -3 <1, F-M9 2, Field rust
G60 _4 <1, F-M4
G60 4 1, F-M4 ---
CRS 0.71 --- 2, Field rust
CRS 1.00 --- 2, Field rust
CRS 2.S7 --- 2, Field rust
CRS 2.87 --- 2, Field rust
CRS 3.63 --- 2, Field rust
CRS 3.90 --- 2, Fieldrust
CRS 3 2
CRS -3 --- 2
CRS 4 2, Field rust
CRS -4 --- 2, Field rust
CRS _5 3,4,3,36, Field rust
CRS _7 1,1,1,
Footnotes for Table 2-6
IWith the same batch of BIPTC, except for replPni.~hmP-nt 2The acid cleaning step and immedi-
ately following rinse step were omitted for this substrate in this in~t~nce. 3Comparison example
with AUTOPHORETIC~ Conditioning Rinse 3180 rather than a BIPT accol dh-g to this inven-
tion. 4Comparison c;x~llpl~ with no BIPT other than rinsing with DI water. 5Comparison examp-
le with no BIPT and with a diLrerellL reactive rinse, AUTOPHORETIC~ Reaction Rinse 2150.
6Individual results from four replicate samples. 7Comparison example with electrophoretic paint
coating rather than autodeposited coating.
concentrations of phosphonate appea~ed to be adequate to produce cured coating with
good appearance as phosphorus co,.~ il-g byproducts built up in the BIPTC.
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TABLE2-7
Substrate M2/L Previousb R~lting after 504 Hours of Salt Spray
TreatedlZn Coated Portion, Field CRS Portion, Field
A60/CRS 0.43 0-15S,Fx,7 ol2s 7
A60/CRS 0.52 o-23S 6 Ol~ 7
A60 0.90 0-2S,FM8,8
A60 1.19 0-4S,F8,8
A60 1.47 ol3s Fs 7
A60 1.61 0-12S, FM8,7
A60/CRS 1.99 0lss Fs 7 0-1,7
A60/CRS 2.19 0-l~,FM9,7 0-1,7
A60 2.74 0_13S 7
A60 3.04 0l3s 7
A60 3.33 0-4S,F2,8
A60/CRS 4.04 ol3s Ft 7 0-1,7
A60/CRS 4.24 o-35S,FM8,5 0-1,7
A60/CRS 5.81 0-l,F8,7 Ol~ 7
A602 4.95 0-2,MD8,6
A602 5.10 0-2S,F~,8
A60/CRS2 5.76 0-l,F8,7 ol2s 7
G60/CRS 0.48 0 36S,D9,5 O_l~s 7
G60/CRS 0.67 0 34s VF6 5 0-1,6
G60 0.96 0-2,D9,7
G60 1.23 0 1 2S D9 7
G60 1.52 0-2,D9,6
G60 1.66 0-2,MD9,6
G60/CRS 2.05 o-3,~8,5 0l2s 7
G60/CRS 2.23 0 3s,~8,5 0-1.7
... Table continued on next p~ge ...
26
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W O 97/09127 PCT~US96/13480
SubstrateM2/L Previously Rating after 504 Hours of Salt Spray
Treated'Zn Coated Portion, FieldCRS Po _:, Field
G60 2.82 ol2s 7
G60 3.38 o-36s, M D8,5
G60 3.85 0-l,D6,7
G60/CRS 4.09 0-2,MD8, 5 0-1,7
G60/CRS 4.19 0-3,MD8, 5 0-1,7
G602 500 0-2,D3,6
G6o2 5.14 o_38s D9 5
G603 - 0-2,MD8, 6
G603 - o34s ~DD8 5
G6O4 - ol4s,7
G604 - 0_13S 7
CRS 0.85 0-1,7
CRS 1.14 0-1,7
CRS 1.57 ol2s 7
CRS 1.72 0-l,VFg,7
CRS 2.72 01,7
CRS 2.99 0-l,VF3, 7
CRS 3.14 0-1,7
CRS 3.28 0-1,7
CRS 3.48 0-l,VF8, 7
CRS 5.05 0-1,7
CRS 5.19 0-1,7
CRS3 - 0-1,7
CRS3 - 0-1,7
CRS4 0-1,7
CRS4 - 0-1,7
... Table continued on next page ...
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W O 97/09127 PCTrUS96/13480
Substrate M2/L Previously RAting after 504 Elours of Salt Spray
Treatedl Zn Coated Portion, Field CRS Portion, Field
CRS5 - 0-1, VF6? 7
CRS5 - 0-1, 7
CRS5 - 1-1, VF8, 7
CRS5 - 0-1, 7
CRS6 - o-lS~ g
CRS6 - 0 ls 7
CRS6 - 0-1 s, 9
CRS6 - O-lS~ 9
Footnotes for Table 2-7
'With the same batch of BIPTC, except for replç~ 2The acid cle~ning step and immedi-
ately following rinse step were omitted for this substrate in this i.lsl~lce. 3Comparison example
with AUTOPHORETIC~ Conditioning Rinse 3180 rather than a BIPT according to this inven-
tion. 4Co...~ on ~ ..pl~ with no BIPT other than rinsing with DI water. 5Comparison examp-
le with no BIPT and with a di~elell~ reactive rinse, AUTOPHORETIC~ Reaction Rinse 2150.
6Colllp~isol1 example with elc~,~lophoretic paint coating rather than autodeposited coating.
Initial adhesion and impact coating test results for co~ting~ over G60 and A60
s~sLl~es were undrrel;led by the amount of sub~ e processed in the best BIPTC ac-
cording to the invention, until at least about 3.7 m2/L of original BIPTC had been pro-
cessed. Confinl-ed use of replenished used BIPTC after that extent of processing resulted
5 in somewhat lower adhesion and impact test values. Coating pelr~ ce for co~ting~
over a CRS substrate did not ~limini~h with continued use of replçni~hed used BIPTC.
Salt spray tests resulted in some field blistering and cathodic del~min~tion spots
for coatings after Lle~ according to the invention on both G60 and A60 substrates.
Variable field blistering was also observed but blister size and/or frequency had no con-
1C sistent trend. All ofthese results are normal for almost any organic coating over zinc-rich
metal surfaces, even for coatings known to give good practical performance. Ratings
showed variability with no appalell~ trend as the area of substrate processed was in-
creased. Coating pelro....~ e was slightly better for coatings over the A60 substrate than
the G60. Salt spray results over CRS were typically 0-1, colll,ual~ble to all the types of
5 co...l-A.;~:oll examples tested, indicating that BIPT according to the invention is not detri-
28
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W O 97/09127 PCT~US96/13480
mental to the quality of autodeposited coatings over CRS, which already give fully satis-
factory coating pelrul-n~lce.
Sclibe/sc~ test results were excell~nt for coating~ aflcer BIPT accordillg to the in-
vention over G60 and A60 substrates: Typical total creep widths for all A60 and G60
s panels were 1 mm or less. Typical creep widths over CRS were 2 mm, closely co-llp~b-
le to those achieved with ~,ullcll~ly prGrellGd coll,-llelcial autodeposition coatings from the
same autodeposition compositions as used here.
