Composition and method for treatment of phosphated metal surfaces

A rinse solution for the treatment of conversion-coated metal substrates for improving the adhesion and corrosion resistance of siccative coatings, comprising an aqueous solution of a Group IVA metal ion, namely, zirconium, titanium, hafnium, and mixtures thereof, and a phenol polymer, with the pH of the total solution about 3.5 to 5.1. A method for treating such materials by applying the rinse solution to the substrate.

BACKGROUND OF THE INVENTION 
This invention relates to the treatment of metal surfaces prior to a 
finishing operation, such as the application of a siccative organic 
coating (also known as an "organic coating", "organic finish", or simply, 
"paint"). Specifically, this invention relates to the treatment of 
conversion-coated metal with an aqueous solution comprising a phenolic 
resin and a Group IVA metal ion, namely zirconium, titanium, hafnium, and 
mixtures thereof. Treatment of conversion-coated metal with such a 
solution improves paint adhesion and corrosion resistance. 
The primary purposes of applying siccative coatings to metal substrates 
(e.g., steel, aluminum, zinc and their alloys) are protection of the metal 
surface from corrosion and for aesthetic reasons. It is well-known, 
however, that many organic coatings adhere poorly to metals in their 
normal state. As a result, corrosion-resistance characteristics of the 
siccative coating are substantially diminished. It is therefore a typical 
procedure in the metal finishing industry to subject metals to a 
pretreatment process whereby a conversion coating is formed on the metal 
surface. This conversion coating acts as a protective layer, slowing the 
onset of the degradation of the base metal, owing to the conversion 
coating being less soluble in a corrosive environment than is the base 
metal. The conversion coating is also effective by serving as a recipient 
for a subsequent siccative coating. The conversion coating has a greater 
surface area than does the base metal and thus provides for a greater 
number of adhesion sites for the interaction between the conversion 
coating and the organic finish. Typical examples of such conversion 
coatings include, but are not limited to, iron phosphate coatings, zinc 
phosphate coatings, and chromate conversion coatings. These conversion 
coatings and others are well-known in the art and will not be described in 
any further detail. 
Normally, the application of an organic finish to a conversion-coated metal 
surface is not sufficient to provide the highest levels of paint adhesion 
and corrosion resistance. Painted metal surfaces are able to reach maximum 
performance levels when the conversion-coated metal surface is treated 
with a "final rinse", also referred to in the art as a "post-rinse" or a 
"seal rinse", prior to the painting operation. Final rinses are typically 
aqueous solutions containing organic or inorganic entities designed to 
improve paint adhesion and corrosion resistance. The purpose of any final 
rinse, regardless of its composition, is to form a system with the 
conversion coating in order to maximize paint adhesion and corrosion 
resistance. This may be accomplished by altering the electrochemical state 
of the conversion-coated substrate by rendering it more passive or it may 
be accomplished by forming a barrier film which prevents a corrosive 
medium from reaching the metal surface. The most effective final rinses in 
general use today are aqueous solutions containing chromic acid, partially 
reduced to render a solution comprising a combination of hexavalent and 
trivalent chromium. Final rinses of this type have long been known to 
provide the highest levels of paint adhesion and corrosion resistance. 
Chromium-containing final rinses, however, have a serious drawback due to 
their inherent toxicity and their hazardous nature. These concerns make 
chromium-containing final rinses less desirable from a practical 
standpoint, when one considers such issues as safe handling of chemicals 
and the environmental problems associated with the discharge of such 
solutions into municipal water streams. Thus, it has been a goal of the 
industry to find chromium-free alternatives which are less toxic and more 
environmentally benign than chromium-containing final rinses. It has also 
been desirous to develop chromium-free final rinses which are as effective 
as chromium-containing final rinses in terms of paint adhesion and 
corrosion resistance properties. 
Much work has already been done in the area of chromium-free final rinses. 
Some of these have utilized either Group IVA chemistry or phenolic 
polymers. U.S. Pat. No. 3,695,942 describes a method of treating 
conversion-coated metal with an aqueous solution containing soluble 
zirconium compounds. U.S. Pat. No. 4,650,526 describes a method of 
treating phosphated metal surfaces with an aqueous mixture of an aluminum 
zirconium complex, an organofunctional ligand and a zirconium oxyhalide. 
The treated metal could be optionally rinsed with deionized water prior to 
painting. U.S. Pat. No. 4,457,790 describes a treatment composition 
utilizing titanium, zirconium and hafnium in aqueous solutions containing 
polymers with chain length from 1 to 5 carbon atoms. U.S. Pat. No. 
4,656,097 describes a method for treating phosphated metal surfaces with 
organic titanium chelates. The treated metal surface can optionally be 
rinsed with water prior to the application of a siccative organic coating. 
U.S. Pat. No. 4,497,656 details a process for treating phosphated metal 
surfaces with solutions containing trivalent titanium and having a pH of 2 
to 7. U.S. Pat. No. 4,457,790 and U.S. Pat. No. 4,517,028 describe a final 
rinse composition comprising a polyalkylphenol and Group IVA metal ion. In 
all of the above examples, the treatment method described claimed to 
improve paint adhesion and corrosion resistance. 
The levels of paint adhesion and corrosion resistance afforded by the 
treatment solutions in the above examples do not reach the levels desired 
by the metal finishing industry, namely the performance characteristics of 
chromium-containing final rinses. I have found that aqueous solutions 
containing a phenolic resin and Group IVA metal ions, namely, zirconium, 
titanium, hafnium, and mixtures thereof, provide paint adhesion and 
corrosion resistance characteristics comparable to those attained with 
chromium-containing final rinses. In many cases, the performance of 
conversion-coated metal surfaces treated with phenolic resin-Group IVA 
metal ion solutions in accelerated corrosion tests exceeds that of 
conversion-coated metal treated with chromium-containing solutions. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a method and composition of an 
aqueous rinse which will impart an improved level of paint adhesion and 
corrosion resistance on painted, conversion-coated metal. The composition 
comprises an aqueous solution containing a phenolic resin and a Group IVA 
metal ion, namely, zirconium, titanium, hafnium, and mixtures thereof, and 
provides levels of paint adhesion and corrosion resistance comparable to 
or exceeding those provided by chromium-containing final rinses. 
It is a further object of the invention to provide a method and rinse 
composition which contains no chromium. 
The presently preferred embodiment of the invention includes a rinse 
solution for the treatment of conversion-coated metal substrates for 
improving the adhesion and corrosion resistance of siccative coatings, 
comprising an aqueous solution of a Group IVA metal ion, namely, 
zirconium, titanium, hafnium, and mixtures thereof, and a phenolic resin, 
with the solution having a pH of about 3.5 to 5.1. 
The invention also includes a method for treating such materials by 
applying the rinse solution to the substrate. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The rinse solution of the invention is an aqueous solution containing a 
phenolic resin and Group IVA metal ion, namely, zirconium, titanium, 
hafnium, and mixtures thereof. It is intended that the rinse solution be 
applied to conversion-coated metal. The formation of conversion coatings 
on metal substrates is well-known within the metal finishing industry. In 
general, this process is usually described as a process requiring several 
pretreatment stages. The actual number of stages is typically dependent on 
the final use of the painted metal article. The number of pretreatment 
steps normally varies anywhere from two to nine stages. A representative 
example of a pretreatment process involves a five-stage operation where 
the metal which will ultimately be painted goes through a cleaning stage, 
a water rinse, a conversion coating stage, a water rinse and a final rinse 
stage. Modifications to the pretreatment process can be made according to 
specific needs. As an example, surfactants can be incorporated into some 
conversion coating baths so that cleaning and the formation of the 
conversion coating can be achieved simultaneously. In other cases it may 
be necessary to increase the number of pretreatment stages so as to 
accommodate more pretreatment steps. Examples of the types of conversion 
coatings that can be formed on metal substrates are iron phosphates and 
zinc phosphates. Iron phosphating is usually accomplished in no more than 
five pretreatment stages, while zinc phosphating usually requires a 
minimum of six pretreatment stages. The number of rinse stages between the 
actual pretreatment steps can be adjusted to ensure that rinsing is 
complete and effective and so that the chemical pretreatment from one 
stage is not carried on the metal surface to subsequent stages, thereby 
possibly contaminating them. It is typical to increase the number of rinse 
stages when the metal parts to be treated have unusual geometries or areas 
that are difficult for the rinse water to contact. The method of 
application of the pretreatment operation can be either an immersion or a 
spray operation. In immersion operations, the metal articles are submersed 
in the various pretreatment baths for defined intervals before moving on 
to the next pretreatment stage. A spray operation is one where the 
pretreatment solutions and rinses are circulated by means of a pump 
through risers fashioned with spray nozzles. The metal articles to be 
treated normally proceed through the pretreatment operation by means of a 
continuous conveyor. Virtually all pretreatment processes can be modified 
to run in spray mode or immersion mode, and the choice is usually made 
based on the final requirements of the painted metal article. It is to be 
understood that the invention described here can be applied to any 
conversion-coated metal surface and can be applied either as a spray 
process or an immersion process. 
The rinse solution of the invention comprises an aqueous solution of a 
phenolic resin and Group IVA metal ion. Specifically, the rinse solution 
is an aqueous solution containing zirconium, titanium, or hafnium ions, 
and mixtures thereof, whose source can be hexafluorozirconic acid, 
hexafluorotitanic acid, hafnium oxide, titanium oxysulfate, titanium 
tetrafluoride, zirconium sulfate and mixtures thereof, and a phenolic 
resin which is a phenol polymer with formaldehyde. The phenolic resin is a 
water soluble base catalyzed condensation product of the reaction between 
phenol and formaldehyde. A present source for such resin is Schenectady 
International, Inc. SP-6877. The resin is typically a mixture of 
substituted phenol compounds, namely: 2-hydroxybenzyl alcohol, 
4-hydroxybenzyl alcohol, 2,6-dimethylol phenol, 2,4-dimethylol phenol and 
2,4,6-trimethylol phenol. 
The rinse solution is prepared by making an aqueous solution using 
deionized water. The solution contains: a Group IVA metal ion, namely, 
zirconium, titanium, hafnium, and mixtures thereof, such that the metal 
ion concentration is about 0.00035% w/w to about 0.005% w/w and that of 
the phenol polymer is about 0.01% w/w to about 0.4% w/w. The aqueous 
solution also contains a water-soluble solvent such as tripropylene glycol 
monomethyl ether to make the solution homogeneous. The pH of the resulting 
solution is adjusted to about 3.5 to 5.1 using sodium hydroxide. 
A preferred version of the invention is an aqueous solution containing 
0.00035 to 0.0016% w/w titanium ion and 0.01 to 0.40% w/w of phenol 
polymer. The resulting solution can be effectively operated at pH 3.5 to 
5.1. 
Another preferred version of the invention is an aqueous solution 
containing 0.00065 to 0.0050% w/w zirconium ion and 0.01 to 0.40% w/w of 
phenol polymer. The resulting solution can be effectively operated at pH 
3.5 to 5.1. 
Another preferred version of the invention is an aqueous solution 
containing 0.00035 to 0.0050% w/w hafnium ion and 0.01 to 0.40% w/w of 
phenol polymer. The resulting solution can be effectively operated at pH 
3.5 to 5.1. 
An especially preferred version of the invention is an aqueous solution 
containing 0.00035 to 0.0010% w/w titanium ion and 0.01 to 0.077% w/w of 
phenol polymer. The resulting solution can be effectively operated at pH 
4.0 to 5.1. 
Another especially preferred version of the invention is an aqueous 
solution containing 0.00065 to 0.0011% w/w zirconium ion and 0.01 to 
0.077% w/w of phenol polymer. The resulting solution can be effectively 
operated at pH 4.0 to 5.1. 
Another especially preferred version of the invention is an aqueous 
solution containing 0.0008 to 0.0010% w/w hafnium ion and 0.01 to 0.077% 
w/w of phenol polymer. The resulting solution can be effectively operated 
at pH 4.0 to 5.1. 
The rinse solution of the invention can be applied by various means, so 
long as contact between the rinse solution and the conversion-coated 
substrate is effected. The preferred methods of application of the rinse 
solution of the invention are by immersion or by spray. In an immersion 
operation, the conversion-coated metal article is submersed in the rinse 
solution of the invention for a time interval from about 5 sec to 5 min, 
preferably 45 sec to 1 min. In a spray operation, the conversion-coated 
metal article comes in contact with the rinse solution of the invention by 
means of pumping the rinse solution through risers fashioned with spray 
nozzles. The application interval for the spray operation is about 5 sec 
to 5 min, preferably 45 sec to 1 min. The rinse solution of the invention 
can be applied at temperatures from about 70.degree. F. to 150.degree. F., 
preferably 70.degree. F. to 90.degree. F. Following treatment in the rinse 
solution, the treated metal article can be optionally post-rinsed with 
deionized water. The use of such a post-rinse is common in many industrial 
electrocoating operations. The conversion-coated metal article treated 
with the rinse solution of the invention can be dried by various means, 
preferably oven drying at about 350.degree. F. for about 5 min. The 
conversion-coated metal article, now treated with the rinse solution of 
the invention, is ready for application of the siccative coating.

EXAMPLES 
The following examples demonstrate the utility of the rinse solution of the 
invention. Comparative examples include conversion-coated metal substrates 
treated with a chromium-containing rinse and conversion-coated metal 
substrates treated with a final rinse solution as described in U.S. Pat. 
No. 4,517,028, which is a final rinse composition comprising a 
polyalkylphenol and Group IVA metal ion. Another comparative example was 
to treat conversion-coated metal substrates with a deionized-water final 
rinse. Throughout the examples, specific parameters for the pretreatment 
process, for the rinse solution of the invention, for the comparative 
rinses and the nature of the substrate and the type of siccative coating 
are described. 
Some of the panels described in the various examples were painted with 
three different electrocoatings, all applied anodically. These were: 
Vectrocoat 300 Gray and Vectrocoat 300 Red, both acrylics, and both 
manufactured by the Valspar Corporation, Garland, Tex. The third 
electrocoat was Unichem E-2000, manufactured by Universal Chemicals & 
Coatings, Elgin Ill. Two other organic coatings that were applied to some 
of the panels were a melamine-modified polyester and a water-based 
coating, both manufactured by the Sheboygan Paint Company, Sheboygan, Wis. 
All treated and painted metal samples were subjected to accelerated 
corrosion testing. In general, the testing was performed according to the 
guidelines specified in ASTM B-117-90. Specifically, three identical 
specimens were prepared for each pretreatment system. The painted metal 
samples received a single, diagonal scribe which broke through the organic 
finish and penetrated to bare metal. All unpainted edges were covered with 
electrical tape. The specimens remained in the salt spray cabinet for an 
interval that was commensurate with the type of siccative coating that was 
being tested. Once removed from the salt spray cabinet, the metal samples 
were rinsed with tap water, dried by blotting with paper towels and 
evaluated. The evaluation was performed by scraping away the loose paint 
and corrosion products from the scribe area with the flat end of a 
spatula. The scraping was performed in such a manner so as only to remove 
loose paint and leave adhering paint intact. In the case of some organic 
finishes, removal of the loose paint and corrosion products from the 
scribe was accomplished by means of a tape pull as specified in ASTM 
B-117-90. Once the loose paint was removed, the scribe areas on the 
specimens were then measured to determine the amount of paint lost due to 
corrosion creepage. Each scribe line was measured at eight intervals, 
approximately 1 mm apart, measured across the entire width of the scribe 
area. The eight values were averaged for each specimen and the averages of 
the three identical specimens were averaged to arrive at the final result. 
The creepage values reported in the following tables reflect these final 
results. 
Example 1 
Cold-rolled steel test panels from Advanced Coating Technologies, 
Hillsdale, Mich. were processed through a five-stage pretreatment 
operation. The panels were cleaned with Brent America, Inc. Chem Clean 
1303, a commercially available alkaline cleaning compound. Once rendered 
water-break-free, the test panels were rinsed in tap water and phosphated 
with Brent America, Inc. Chem Cote 3011, a commercially available iron 
phosphate. The phosphating bath was operated at about 6.2 points, 
140.degree. F., 3 min contact time, pH 4.8. After phosphating, the panels 
were rinsed in tap water and treated with various final rinse solutions 
for 1 min. The panels were given a deionized-water post-rinse prior to 
dry-off. The comparative chromium-containing rinse was Brent America, Inc. 
Chem Seal 3603, a commercially available product. This bath was run at 
0.25% w/w. In accordance with normal practice in the metal finishing 
industry, panels treated with the chromium-containing final rinse (1) were 
rinsed with deionized water prior to dry-off. Panels treated with the 
comparative chromium-free final rinse(2) were obtained from Advanced 
Coating Technologies, Hillsdale, Mich. identified by Code APR20809. All 
panels treated in the laboratory were then dried in an oven at 350.degree. 
F. for 5 min. The panels were painted with Vectrocoat 300 Gray, Vectrocoat 
300 Red, Unichem E-2000, the water-based coating, and the 
melamine-modified polyester. The various rinses studied are summarized as 
follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
2. Comparative chromium-free final rinse. 
3. Phenol polymer, 0.01% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
4. Phenol polymer, 0.50% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
5. Phenol polymer, 0.30% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
6. Phenol polymer, 0.40% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
The salt spray results are described in Tables I and II and III. The values 
represent total creepage about the scribe area in mm. The numbers in 
parentheses represent the exposure interval for that particular organic 
finish. 
Example 2 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with Vectrocoat 300 Gray, Vectrocoat 300 Red, and the water-based 
coating. The various final rinses are summarized as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
2. Comparative chromium-free final rinse. 
7. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
8. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00060% w/w. 
9. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00085% w/w. 
10. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00110% w/w. 
11. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00135% w/w. 
12. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00160% w/w. 
13. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00185% w/w. 
The salt spray results are described in Table IV. The values represent 
total creepage about the scribe area in mm. The numbers in parentheses 
represent the exposure interval for that particular organic finish. 
Example 3 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with Vectrocoat 300 Gray, Vectrocoat 300 Red, Unichem E-2000, and 
the melamine-modified polyester. The various final rinses are summarized 
as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
2. Comparative chromium-free final rinse. 
14. Phenol polymer, 0.077% w/w, pH 3.50, Ti concentration, 0.00035% w/w. 
15. Phenol polymer, 0.077% w/w, pH 5.10, Ti concentration, 0.00035% w/w. 
16. Phenol polymer, 0.077% w/w, pH 3.00, Ti concentration, 0.00035% w/w. 
17. Phenol polymer, 0.077% w/w, pH 5.40, Ti concentration, 0.00035% w/w. 
The salt spray results are described in Tables V and VI. The values 
represent total creepage about the scribe area in mm. The numbers in 
parentheses represent the exposure interval for that particular organic 
finish. 
Example 4 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The final rinse was applied by an 
immersion technique on some conversion-coated panels and was applied by 
means of a recirculating spray on others. The conversion-coated test 
panels were painted with Vectrocoat 300 Gray, Vectrocoat 300 Red, Unichem 
E-2000, and the melamine-modified polyester. The various final rinses are 
summarized as follows. 
7. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, 
spray application. 
18. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, 
immersion application. 
The salt spray results are described in Table VII. The values represent 
total creepage about the scribe area in mm. The numbers in parentheses 
represent the exposure interval for that particular organic finish. 
Example 5 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with Vectrocoat 300 Red and the water-based coating. The various 
final rinses are summarized as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
19. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, Zr 
concentration, 0.00066% w/w. 
20. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, Hf 
concentration, 0.00035% w/w. 
21. Phenol polymer, 0.077% w/w, pH 4.00, Zr concentration, 0.00066% w/w, Hf 
concentration, 0.00035% w/w. 
22. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, Zr 
concentration, 0.00066% w/w, Hf concentration, 0.00035% w/w. 
The salt spray results are described in Table VIII. The values represent 
total creepage about the scribe area in mm. The numbers in parentheses 
represent the exposure interval for that particular organic finish. 
Example 6 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with Vectrocoat 300 Red, Vectrocoat Gray, Unichem E-2000, the 
melamine-modified polyester and the water-based coating. The various final 
rinses are summarized as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
23. Phenol polymer, 0.077% w/w, pH 4.00, Zr concentration, 0.00065% w/w. 
24. Phenol polymer, 0.077% w/w, pH 4.00, Zr concentration, 0.0050% w/w. 
25. Phenol polymer, 0.077% w/w, pH 4.00, Zr concentration, 0,0011% w/w. 
26. Phenol polymer, 0.077% w/w, pH 4.00, Hf concentration, 0.0010% w/w. 
27. Phenol polymer, 0.077% w/w, pH 4.00, Hf concentration, 0.0008% w/w. 
28. Phenol polymer, 0.077% w/w, pH 4.00, Hf concentration, 0.0050% w/w. 
The salt spray results are described in Tables IX, X, XI and XII. The 
values represent total creepage about the scribe area in mm. The numbers 
in parentheses represent the exposure interval for that particular organic 
finish. 
Example 7 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with Vectrocoat 300 Red and Veotrocoat 300 Gray. The various final 
rinses are summarized as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
29. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w. 
30. Phenol polymer, 0.077% w/w, pH 4.00, Zr concentration, 0.00065% w/w. 
The salt spray results are described in Table XIII. The values represent 
total creepage about the scribe area in mm. The numbers in parentheses 
represent the exposure interval for that particular organic finish. 
Example 8 
Another set of cold-rolled steel test panels was prepared using the 
parameters described in Example 1. The conversion-coated test panels were 
painted with the melamine-modified polyester. The various final rinses are 
summarized as follows. 
1. Chem Seal 3603, chromium-containing final rinse. 
31. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, 
followed by a deionized water post-rinse. 
32. Phenol polymer, 0.077% w/w, pH 4.00, Ti concentration, 0.00035% w/w, 
without a deionized water post-rinse. 
The salt spray results are described in Table XIV. The values represent 
total creepage about the scribe area in mm. The numbers in parentheses 
represent the exposure interval for that particular organic finish. 
The results from accelerated corrosion testing demonstrated in Examples 1 
to 8 show that rinse solutions containing a phenolic resin and a Group IVA 
metal ion provided substantially better performance than the comparative 
chromium-free rinse, Rinse No. 2. The results demonstrated in Examples 1 
to 8 also show that rinse solutions containing a phenolic resin and Group 
IVA metal ion, namely zirconium, titanium, hafnium and mixtures thereof, 
provided, in many cases, corrosion resistance comparable to that of a 
chromium-containing rinse, such as Final Rinse No. 1. In several 
instances, rinse solutions containing a phenolic resin and Group IVA metal 
ion, namely, zirconium, titanium, hafnium, and mixtures thereof, provided 
significantly higher levels of corrosion resistance than that achieved 
with a chromium-containing rinse. 
The terms and expressions which have been employed are used as terms of 
description and not of limitation, and there is no intention in the use of 
such terms and expressions of excluding any equivalents of the features 
shown and described, or portions thereof, but it is recognized that 
various modifications are possible within the scope of the invention 
claimed. 
TABLE I 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 7.8 9 7.3 8.3 
2 10.5 14.7 4.2 8.8 
3 7.9 9.4 4.3 14.8 
__________________________________________________________________________ 
TABLE II 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 15.5 11.2 14.3 6.1 
4 16.8 21.9 14.9 32.7 
__________________________________________________________________________ 
TABLE III 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (120 hr) 
Water-based (168 hr) 
__________________________________________________________________________ 
1 14.7 16 7 
5 19.1 17 6.3 
6 10.4 10.2 6.1 
__________________________________________________________________________ 
TABLE IV 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (120 hr) 
Water-based (168 hr) 
__________________________________________________________________________ 
1 12.1 11.5 5.7 
7 8.4 12.4 2.2 
8 3.5 6.7 2 
9 5.5 6.4 1.9 
10 5.8 7.5 2.4 
11 6.6 9.9 3 
12 9.2 11 3.3 
13 9.5 12.9 22.9 
__________________________________________________________________________ 
TABLE V 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 7.8 9 7.3 8.3 
2 10.5 14.7 4.2 8.8 
14 8.8 9.5 5.1 10.3 
15 6.2 5.8 6.5 3.9 
__________________________________________________________________________ 
TABLE VI 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 15.5 11.2 14.3 6.1 
16 23.2 13.8 10.6 16.4 
17 18.1 29.4 18.1 41.8 
__________________________________________________________________________ 
TABLE VII 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
7 4.3 4.7 4.7 4.5 
18 7.1 3.3 9.4 3.5 
__________________________________________________________________________ 
TABLE VIII 
______________________________________ 
Final Rinse No. 
Water-based (216 hr) 
300 Red (120 hr) 
______________________________________ 
1 4.1 7.2 
19 3.5 6.2 
20 2.7 6.3 
21 2.6 3.9 
22 3.6 6.6 
______________________________________ 
TABLE IX 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Unichem (504 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 7.8 9 7.3 8.3 
23 5.5 4.7 5.9 4 
__________________________________________________________________________ 
TABLE X 
__________________________________________________________________________ 
Final Rinse No. 
300 Red (96 hr) 
300 Gray (120 hr) 
Unichem (336 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 15.9 24 20.4 28.9 
25 7.3 10.9 2.6 38.6 
26 5.3 6.5 1.6 5.5 
__________________________________________________________________________ 
TABLE XI 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Melamine (144 hr) 
__________________________________________________________________________ 
1 56.7 17.2 30.5 
27 11.7 5.8 1.9 
__________________________________________________________________________ 
TABLE XII 
__________________________________________________________________________ 
Final Rinse No. 
300 Gray (120 hr) 
300 Red (96 hr) 
Water-based (120 hr) 
__________________________________________________________________________ 
1 24.7 20.8 24.5 
24 22.1 19.8 10.8 
28 9.3 12.9 10.7 
__________________________________________________________________________ 
TABLE XIII 
______________________________________ 
Final Rinse No. 
300 Gray (96 hr) 
300 Red (96 hr) 
______________________________________ 
1 9 9.6 
29 5.1 8.3 
30 9.2 N/A 
______________________________________ 
TABLE XIV 
______________________________________ 
Final Rinse No. 
Melamine (168 hr) 
______________________________________ 
1 8.8 
31 6.1 
32 2.4 
______________________________________ 
The rinses numbers 3 through 32 provided results at least as good as the 
results for the conventional chromium rinse number 1, and are considered 
acceptable examples of the present invention. Rinses with compositions 
outside the ranges of rinses 3-32 were also tested but provided 
unacceptable results.