U.S. patent application number 12/077429 was filed with the patent office on 2008-09-25 for metal surface treatment liquid for cation electrodeposition coating.
Invention is credited to Toshio Inbe, Hiroshi Kameda, Thomas Kolberg.
Application Number | 20080230394 12/077429 |
Document ID | / |
Family ID | 39536365 |
Filed Date | 2008-09-25 |
United States Patent
Application |
20080230394 |
Kind Code |
A1 |
Inbe; Toshio ; et
al. |
September 25, 2008 |
Metal surface treatment liquid for cation electrodeposition
coating
Abstract
A surface treatment with a zirconium ion that enables sufficient
throwing power, and superior anti-corrosion properties to be
exhibited when thus surface treated metal base material is
subjected to cation electrodeposition coating is provided. A metal
surface treatment liquid for cation electrodeposition coating
includes zirconium ions and tin ions, and has a pH of 1.5 to 6.5,
in which: the concentration of zirconium ions is in the range of 10
to 10,000 ppm; and the content of the tin ions to the zirconium
ions is 0.005 to 1 on a mass basis. Furthermore, a polyamine
compound, copper ions, fluorine ions, and a chelate compound may
also be included.
Inventors: |
Inbe; Toshio; (Tokyo,
JP) ; Kameda; Hiroshi; (Tokyo, JP) ; Kolberg;
Thomas; (Heppenheim, DE) |
Correspondence
Address: |
DILWORTH & BARRESE, LLP
333 EARLE OVINGTON BLVD., SUITE 702
UNIONDALE
NY
11553
US
|
Family ID: |
39536365 |
Appl. No.: |
12/077429 |
Filed: |
March 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2007/074536 |
Dec 20, 2007 |
|
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12077429 |
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Current U.S.
Class: |
205/241 ;
205/238 |
Current CPC
Class: |
C25D 13/04 20130101;
C25D 13/20 20130101; C23C 2222/20 20130101; C25D 3/56 20130101;
C25D 3/60 20130101; C23C 22/34 20130101 |
Class at
Publication: |
205/241 ;
205/238 |
International
Class: |
C25D 3/56 20060101
C25D003/56 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2006 |
JP |
2006-343621 |
Apr 27, 2007 |
JP |
2007-119665 |
Nov 22, 2007 |
JP |
2007-303746 |
Claims
1-13. (canceled)
14. A metal surface treatment liquid for cation electrodeposition
coating comprising zirconium ions and tin ions, and having a pH of
1.5 to 6.5, wherein: a concentration of zirconium ions is in the
range of 10 to 10,000 ppm; and a concentration ratio of the tin
ions to the zirconium ions is in the range of 0.005 to 1 on a mass
basis.
15. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14 further comprising a polyamine
compound.
16. A metal surface treatment liquid for cation electrodeposition
coating according to claim 15 wherein said polyamine compound is a
condensate of aminosilane hydrolysate.
17. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further comprising copper ions.
18. A metal surface treatment liquid for cation electrodeposition
coating according to claim 15, further comprising copper ions.
19. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further comprising fluorine ions,
wherein the amount of free fluorine ions at a pH of 3.0 is in the
range of 0.1 to 50 ppm.
20. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further comprising a chelate
compound.
21. A metal surface treatment liquid for cation electrodeposition
coating according to claim 20, wherein the chelate compound is
sulfonic acid.
22. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further comprising an oxidizing
agent.
23. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further containing nitric acid,
wherein the concentration of said nitric acid is in the range of
100 ppm to 100000 ppm.
24. A metal surface treatment liquid for cation electrodeposition
coating according to claim 14, further comprising at least one ion
selected from the group consisting of aluminum ions and indium
ions.
25. A metal surface treatment liquid for cation electrodeposition
coating according to claim 15, further comprising at least one ion
selected from the group consisting of aluminum ions and indium
ions.
26. A metal surface treatment liquid for cation electrodeposition
coating according to claim 16, further comprising at least one ion
selected from the group consisting of aluminum ions and indium
ions.
27. A metal surface treatment liquid for cation electrodeposition
coating according to claim 23, further comprising at least one ion
selected from the group consisting of aluminum ions and indium
ions.
28. A method of metal surface treatment comprising a step of
subjecting a metal base material to a surface treatment with the
metal surface treatment liquid for cation electrodeposition coating
according to claim 14.
29. A metal base material comprising a coating film formed by a
surface treatment obtained by the method according to claim 28.
30. A metal base material according to claim 29, wherein an element
ratio of zirconium/tin on a mass basis in the coating film is in
the range of 1/10 to 10/1.
31. A method of cation electrodeposition coating comprising steps
of: subjecting a metal base material to a surface treatment with
the metal surface treatment liquid according to claim 14, and to
washing with water; and subjecting the surface treated metal base
material to cation electrodeposition coating.
32. A metal base material coated by the cation electrodeposition
obtained with the method according to claim 31.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] The present application is a continuation of PCT application
no. PCT/JP2007/074536 filed Dec. 20, 2007.
TECHNICAL FIELD
[0002] The present invention relates to a metal surface treatment
liquid, particularly to a metal surface treatment liquid suited for
cation electrodeposition coating, and a method of metal surface
treatment.
BACKGROUND ART
[0003] In order to impart anti-corrosion properties to various
metal base materials, surface treatments have thus far been
performed. Particularly, a zinc phosphate treatment has been
generally employed on metal base materials which constitute
automobiles. However, this zinc phosphate treatment has a problem
of sludge generation as a by-product. Accordingly, a surface
treatment without use of zinc phosphate for a next generation has
been demanded, and a surface treatment with zirconium ions is one
of such treatments (see, for example, Patent Document 1).
[0004] Meanwhile, metal base materials which constitute automobiles
and necessitate high anti-corrosion properties are subjected to
cation electrodeposition coating following the surface treatment.
The cation electrodeposition coating is carried out on the grounds
that the coated film obtained by cation electrodeposition coating
has superior anti-corrosion properties, and it has "throwing
power", generally referred to, that is a property of allowing
automobile bodies having a complicated shape to be completely
coated.
[0005] However, it has been recently proven that when a metal base
material which had been surface treated with the zirconium ions is
subjected to the cation electrodeposition coating, there may be a
case in which no significant effect in terms of the throwing power
is achieved, for example, the throwing power may not be sufficient
for cold-rolled steel plates in some cases. Accordingly, when the
cation electrodeposition coating is carried out, sufficient
anti-corrosion properties cannot be achieved if the throwing power
is insufficient.
[0006] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2004-218070
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0007] An object of the present invention is to provide a surface
treatment with zirconium ions that enables sufficient throwing
power and exhibit superior anti-corrosion properties to be
exhibited, when thus surface treated metal base material is
subjected to cation electrodeposition coating.
Means for Solving the Problems
[0008] Aspects of the present invention are as follows. In a first
aspect of the present invention, a metal surface treatment liquid
for cation electrodeposition coating contains zirconium ions, and
tin ions, and has a pH of in the range of 1.5 to 6.5, in which: the
concentration of the zirconium ions is in the range of 10 to 10,000
ppm; and the concentration ratio of the tin ions to the zirconium
ions is 0.005 to 1 on a mass basis.
[0009] In a second aspect of the present invention, a metal surface
treatment liquid for cation electrodeposition coating according to
the first aspect further includes a polyamine compound.
[0010] In a third aspect of the present invention, a metal surface
treatment liquid for cation electrodeposition coating according to
the first or second aspect further includes copper ions.
[0011] In a forth aspect of the present invention, a metal surface
treatment liquid for cation electrodeposition coating according to
any one of the first to third aspects further includes fluorine
ions, in which the amount of free fluorine ions at a pH of 3.0 is
the range of 0.1 to 50 ppm.
[0012] In a fifth aspect of the present invention, a metal surface
treatment liquid for cation electrodeposition coating according to
any one of the first to forth aspects further includes a chelate
compound.
[0013] In a sixth aspect of the metal surface treatment liquid for
cation electrodeposition coating according to the fifth aspect of
the present invention, the chelate compound is sulfonic acid.
[0014] In a seventh aspect of the present invention, a metal
surface treatment liquid for cation electrodeposition coating
according to any one of the first to sixth aspects further includes
an oxidizing agent.
[0015] In an eighth aspect of the present invention, a metal
surface treatment liquid for cation electrodeposition coating
according to any one of the first to seventh aspects further
includes at least one ions selected from the group consisting of
aluminum ions and indium ions.
[0016] In a ninth aspect of the present invention, a method of
metal surface treatment includes a step of subjecting a metal base
material to a surface treatment with the metal surface treatment
liquid for cation electrodeposition coating according to any one of
the first to eighth aspects.
[0017] In a tenth aspect of the present invention, a metal base
material includes a coating film formed by a surface treatment
obtained by the method of metal surface treatment according to the
ninth aspect.
[0018] In an eleventh aspect of the present invention, a metal base
material including a coating film having an element ratio of
zirconium/tin on a mass basis being 1/10 to 10/1 formed on the
metal base material according to the tenth aspect.
[0019] In a twelfth aspect of the present invention, a method of
cation electrodeposition coating includes: the step of subjecting a
metal base material to a surface treatment with the metal surface
treatment liquid for cation electrodeposition coating according to
any one of the first to eighth aspects; and a step of subjecting
the surface treated metal base material to cation electrodeposition
coating.
[0020] In a thirteenth aspect of the present invention, a metal
base material coated by the cation electrodeposition is obtained
with the method of cation electrodeposition coating according to
the twelfth aspect.
[0021] Accordingly, the metal surface treatment liquid for cation
electrodeposition coating of the present invention is a chemical
conversion treatment liquid containing zirconium ions and tin ions,
and having a pH in the range of 1.5 to 6.5, in which the
concentration of zirconium ions in the range of 10 to 10,000 ppm,
and the content of the tin ions with respect to the zirconium ions
is 0.005 to 1 on a mass basis. Moreover, the metal surface
treatment liquid for cation electrodeposition coating may further
contain a polyamine compound, copper ions, fluorine ions, a chelate
compound, an oxidizing agent, and a rust-preventive agent. When the
fluorine ions are included, the amount of free fluorine ions at a
pH of 3.0 may be 0.1 to 50 ppm.
[0022] The method of metal surface treatment of the present
invention includes the step of subjecting a metal base material to
a surface treatment with the abovementioned metal surface treatment
liquid.
[0023] A coating film obtained by the surface treatment is formed
on the surface treated metal base material of the present
invention. The element ratio of zirconium/tin on mass basis in the
coating film may be 1/10 to 10/1.
[0024] The method of cation electrodeposition coating of the
present invention includes a step of subjecting a metal base
material to a surface treatment with the abovementioned metal
surface treatment liquid, and a step of subjecting the surface
treated metal base material to cation electrodeposition
coating.
[0025] The metal base material coated by the cation
electrodeposition of the present invention is obtained by the
abovementioned method of coating.
EFFECTS OF THE INVENTION
[0026] It is believed that the throwing power attained by the metal
surface treatment liquid for cation electrodeposition coating of
the present invention can be improved by including tin ions in
addition to zirconium ions when the cation electrodeposition
coating is carried out after forming a conversion coating film with
this treatment liquid. Although not clarified, the grounds are
conceived as follows.
[0027] When zirconium ions are used alone, formation of their oxide
coating film is believed to be executed simultaneously with etching
of the metal base material in an acidic medium. However, since
segregation materials and the like of compounds containing silicon
or carbon in addition to silica may be present on cold-rolled steel
plates, such parts are not susceptible to etching. Therefore, the
coating film cannot be uniformly formed with zirconium oxide,
whereby portions without coating film formation can be present.
Since a difference in electric current flow is believed to be
generated between the parts with and without formation of the
coating film, the electrodeposition is not uniformly executed, and
consequently, the throwing power cannot be sufficiently
attained.
[0028] When tin ions are additionally present, it is further
considered as in the following. Since the tin ions are less likely
to be affected on the steel plate as compared with the zirconium
ions, their oxide coating film can be more easily formed on the
base material. Although formation of the coating film of the tin
ions is not specific to the parts where the zirconium ions are not
significantly deposited, formation of the oxide coating film of the
tin ions is not restricted to a specific part while having another
part remain without formation of the film. As a result, the tin
ions would form the coating film such that it covers the part where
the zirconium ion could not form the coating film.
[0029] The metal surface treatment liquid for cation
electrodeposition coating of the present invention can improve
adhesiveness to the coated film by cation electrodeposition through
including the polyamine compound, and consequently, it can pass SDT
test under more stringent conditions. In addition, the metal
surface treatment liquid for cation electrodeposition coating of
the present invention can improve anti-corrosion properties by
including the copper ion. Although the grounds are not clarified,
it is believed that some interaction may be caused between copper
and zirconium in forming the coating film. Furthermore, the metal
surface treatment liquid for cation electrodeposition coating of
the present invention can form a zirconium oxide coating film in a
stable manner by including a chelate compound when a metal other
than zirconium is included in large quantity. This occurrence is
believed to result from capture by the chelate compound of metal
ions that are more likely to be deposited than zirconium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 shows a perspective view illustrating one example of
the box for use in evaluating the throwing power; and
[0031] FIG. 2 shows a view schematically illustrating evaluation of
the throwing power.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
[0032] The metal surface treatment liquid for cation
electrodeposition coating of the present invention is a chemical
conversion treatment liquid that contains zirconium ions and tin
ions, and has a pH in the range of 1.5 to 6.5.
[0033] The zirconium ions are included at a concentration in a
range of 10 to 10,000 ppm. When the concentration is less than 10
ppm, sufficient anti-corrosion properties cannot be achieved since
deposition of the zirconium coating film is not enough. In
addition, even though the concentration may exceed 10,000 ppm, an
effect to justify the amount cannot be exhibited since the
deposition amount of the zirconium coated film is not increased,
and adhesiveness of the coated film may be deteriorated, thereby
leading to inferior anticorrosion performance such as those in SDT.
The lower limit and the upper limit of the concentration are
preferably 100 ppm and 500 ppm, respectively.
[0034] The concentration of the metal ions herein, when a complex
or oxide thereof was formed, is represented by the concentration
based on the metal element, taking into account only of the metal
atom in the complex or oxide. For example, the concentration based
on the metal element of zirconium of 100 ppm complex ions
ZrF.sub.6.sup.2- (molecular weight: 205) is calculated to be 44 ppm
by the formula of 100.times.(91/205). In the metal surface
treatment liquid for cation electrodeposition coating of the
present invention, the metal compound (zirconium compound, tin
compound, copper compound and other metal compounds) is included at
just a slight proportion, if present, in the state of a nonionic
state such as an oxide portion, and is believed to be present
almost in the form of the metal ion. Therefore, the metal ion
concentration referred to herein is, irrespective of the presence
in the form of the nonionic portion, the metal ion concentration
when it is assumed to be present as the metal ion dissociated at a
level of 100%.
[0035] The tin ion included in the metal surface treatment liquid
for cation electrodeposition coating of the present invention is
preferably a bivalent cation. When the tin ion has other valence,
the intended effect may not be exhibited. However, the tin ion is
not limited to the bivalent cation, but can be used in the present
invention as long as it can be deposited on the metal base
material. For example, when the tin ions form a complex, it may be
a quadrivalent cation, which can also be used in the present
invention. The concentration of the tin ions is 0.005 to 1 on a
mass basis with respect to the concentration of the zirconium ions.
When the ratio is less than 0.005, the effect by addition is not
exhibited, while zirconium may not be significantly deposited when
the ratio exceeds 1. The lower limit and the upper limit of the
concentration are preferably 0.02 and 0.2, respectively. However,
when the total amount of the zirconium ion and tin ion is too
small, the effect of the present invention may not be exhibited.
Therefore, the total concentration of the zirconium ion and the tin
ion in the metal surface treatment liquid of the present invention
is preferably no less than 15 ppm.
[0036] The content of the tin ions in the metal surface treatment
liquid of the present invention is preferably is preferably 1 to
100 ppm. When the content is less than 1 ppm, deposition of tin at
the portion where zirconium could not form the coating film may be
insufficient, and the anti-corrosion properties such as those in
SDT are likely to be inferior. When the content exceeds 100 ppm,
deposition of the zirconium coating film may be difficult, whereby
the anti-corrosion properties and the coating appearance are likely
to be inferior. The concentration is more preferably 5 to 100 ppm,
and still more preferably 5 to 50 ppm.
[0037] The metal surface treatment liquid for cation
electrodeposition coating of the present invention has a pH in the
range of 1.5 to 6.5. When the pH is less than 1.5, the metal base
material cannot be sufficiently etched to decrease the coating film
amount, and sufficient anti-corrosion properties cannot be
achieved. In addition, the stability of the treatment liquid may
not be sufficient. In contrast, when the pH is higher than 6.5,
excessive etching may lead to failure in formation of sufficient
coating film, or an un-uniform adhesion amount and film thickness
of the coating film may adversely affect the coating appearance and
the like. The lower limit and the upper limit of pH are preferably
2.0 and 5.5, and still more preferably 2.5 and 5.0,
respectively.
[0038] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may further
include a polyamine compound for improving adhesiveness to the
coated film by cation electrodeposition which is formed after the
surface treatment. The polyamine compound used in the present
invention is believed to be fundamentally significant in being an
organic molecule having an amino group. Although speculative, the
amino group is believed to be incorporated in the coating film by a
chemical action with zirconium oxide deposited as a coating film on
the metal base plate, or with the metal base plate. In addition,
the polyamine compound that is an organic molecule is believed to
be responsible for adhesiveness with the coated film provided on
the metal base plate having the coating film formed thereon.
Therefore, when the polyamine compound that is an organic molecule
having an amino group is used, adhesiveness between the metal base
plate and the coated film is significantly improved, and superior
corrosion resistance can be attained. Examples of the polyamine
compound include hydrolysis condensates of aminosilane,
polyvinylamine, polyallylamine, water soluble phenolic resins
having an amino group, and the like. Since the amount of amine can
be freely adjusted, the hydrolysis condensate of aminosilane is
preferred. Therefore, exemplary metal surface treatment liquids for
cation electrodeposition coating of the present invention include,
for example, the metal surface treatment liquids for cation
electrodeposition coating which contain zirconium ions, tin ions,
and a hydrolysis condensate of aminosilane; the metal surface
treatment liquids for cation electrodeposition coating which
contain zirconium ions, tin ions, and polyallylamine; and the metal
surface treatment liquids for cation electrodeposition coating
which contain zirconium ions, tin ions, and a water soluble
phenolic resin having an amino group. In addition, these metal
surface treatment liquids for cation electrodeposition coating may
contain fluorine as described later.
[0039] The hydrolysis condensate of aminosilane is obtained by
carrying out hydrolysis condensation of an aminosilane compound.
Examples of the aminosilane compound include vinyltrichlorosilane,
vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4
epoxycyclohexyl)-ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropylmethyldiethoxysilane,
3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane,
3-methacryloxypropylmethyldimethoxysilane,
3-methacryloxypropyltrimethoxysilane,
3-methacryloxypropylmethyldiethoxysilane,
3-methacryloxypropyltriethoxysilane,
3-acryloxypropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropyltriethoxysilane,
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
3-triethoxysilyl-N-(1,3-dimethyl-butylidene)-propylamine,
N-phenyl-3-aminopropyltrimethoxysilane,
N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane
hydrochloride, 3-ureidepropyltriethoxysilane,
3-chloropropyltrimethoxysilane,
3-mercaptopropylmethyldimethoxysilane,
3-mercaptopropyltrimethoxysilane,
bis(triethoxysilylpropyl)tetrasulfide, and 3-isocyanate
propyltriethoxysilane, which are silane coupling agents having an
amino group. In addition, examples of commercially available
products which can be used include "KBM-403", "KBM-602", "KBM-603",
"KBE-603", "KBM-903", "KBE-903", "KBE-9103", "KBM-573", "KBP-90"
(all trade names, manufactured by Shin-Etsu Chemical Co.,),
"XS1003" (trade name, manufactured by Chisso Corporation), and the
like.
[0040] The hydrolytic condensation of the aforementioned
aminosilane can be carried out by a method well known to persons
skilled in the art. Specifically, the hydrolytic condensation can
be carried out by adding water required for hydrolysis of the
alkoxysilyl group to at least one kind of aminosilane compound, and
stirring the mixture while heating as needed. The degree of
condensation can be regulated with the amount of water used.
[0041] A higher degree of condensation of aminosilane hydrolysis
condensate is preferred, since in this case where zirconium is
deposited as an oxide, the above aminosilane hydrolysis condensate
tends to be easily incorporated therein. For example, the portion
on a mass basis of dimer or higher-order multimers of aminosilane
in the total amount of the aminosilane is preferably no less than
40%, more preferably no less than 50%, still more preferably no
less than 70%, and even more preferably no less than 80%.
Therefore, when aminosilane is allowed to react in a hydrolytic
condensation reaction, it is preferred to permit the reaction under
conditions in which aminosilane is more likely to be hydrolysed and
condensed such as those in which an aqueous solvent containing a
catalyst such as acetic acid and alcohol is used as the solvent. In
addition, by allowing for a reaction under conditions with a
comparatively high aminosilane concentration, a hydrolysis
condensate having a high degree of condensation is obtained.
Specifically, it is preferred to allow for the hydrolytic
condensation at an aminosilane concentration falling within the
range of 5% by mass to 50% by mass. The degree of condensation can
be determined by .sup.29Si--NMR measurement.
[0042] As the polyvinylamine and polyallylamine, commercially
available products can be used. Examples of polyvinylamine include
"PVAM-0595B" (trade name, manufactured by Mitsubishi Chemical
Corporation) and the like, and examples of the polyallylamine
include "PAA-01", "PAA-10C", "PAA-H-10C", "PAA-D-41HCl" (all trade
names, manufactured by Nitto Boseki Co., Ltd.) and the like.
[0043] The molecular weight of the polyamine compound is preferably
in the range of 150 to 500,000. When the molecular weight is less
than 150, a conversion coating film having sufficient adhesiveness
may not be obtained. When the molecular weight exceeds 500,000,
formation of the coating film may be inhibited. The lower limit and
the upper limit are more preferably 5,000 and 70,000, respectively.
When the polyamine compound has the amino group in too large an
amount, it may adversely influence the coating film, while the
effect to improve the adhesiveness with the coating film provided
by the amino group is not significantly achieved when the amount is
too small. Therefore, the polyamine compound preferably has a
primary and/or secondary amino group of no less than 0.1 mmol and
no more than 17 mmol per gram of the solid content, and more
preferably a primary and/or secondary amino group of no less than 3
mmol and no more than 15 mmol per gram of the solid content.
[0044] The number of moles of the primary and/or secondary amino
group per gram of the solid content of the polyamine compound can
be determined according to the following formula (I).
Amount of Amino Group=(mX-nY)/(m+n) Formula (1)
[0045] in which the mass ratio of solid contents of the polyamine
compound and the compound having a functional group A and/or a
functional group B is defined as m:n; the number of mmoles of the
functional group A and/or the functional group B per gram of the
compound having the functional group A and/or the functional group
B is defined as Y; and the number of mmoles of the primary and/or
secondary amino group included per gram of the polyamine compound
when the compound having the functional group A and/or the
functional group B is not included in the composition for the metal
surface treatment is defined as X.
[0046] The content of the polyamine compound in the metal surface
treatment liquid for cation electrodeposition coating of the
present invention can be in the range of 1 to 200% based on mass of
the zirconium metal included in the surface treatment liquid. When
the content is less than 1%, the intended effect cannot be
exhibited, while the content exceeding 200% may lead to failure in
sufficient formation of the coating film. The upper limit of the
content is more preferably 120%, more preferably 100%, still more
preferably 80%, and even more preferably 60%.
[0047] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may further
contain a copper ion for improving the anti-corrosion properties.
With respect to the amount of the copper ions, the concentration
preferably accounts for 10 to 100% with respect to the
concentration of the tin ions. When the concentration is less than
10%, the intended effect may not be exhibited, while deposition of
zirconium may be difficult, similarly to the case of the tin ions
when it exceeds the concentration of the tin ions. Exemplary metal
surface treatment liquids for cation electrodeposition coating of
the present invention include, for example, the metal surface
treatment liquids for cation electrodeposition coating which
contain zirconium ions, tin ions and copper ions. In this case, the
fluorine ions described later can be further included and the
aforementioned polyamine compound can be included.
[0048] It is preferred that the metal surface treatment liquid for
cation electrodeposition coating of the present invention contains
fluorine ions. Since the concentration of the fluorine ions varies
depending on the pH, the amount of free fluorine ions is defined at
a specified pH. In the present invention, the amount of the free
fluorine ions at a pH of 3.0 is in the range of 0.1 to 50 ppm. When
the amount is less than 0.1 ppm, the metal base material cannot be
sufficiently etched so that the coating film amount is decreased,
and sufficient anticorrosion properties cannot be achieved. In
addition, the treatment liquid may not have enough stability. In
contrast, when the amount is above 50 ppm, excessive etching may
lead to failure in formation of sufficient coating film, or an
un-uniform adhesion amount and film thickness of the coating film
may adversely affect the coating appearance and the like. The lower
limit and the upper limit are preferably 0.5 ppm and 10 ppm,
respectively. Exemplary metal surface treatment liquids for cation
electrodeposition coating of the present invention include, for
example, the metal surface treatment liquids for cation
electrodeposition coating which contain zirconium ions, tin ions,
and fluorine ions.
[0049] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may include a
chelate compound. By including the chelate compound, deposition of
metals other than zirconium can be suppressed in the treatment
liquid, and the coating film of zirconium oxide can be stably
formed. As the chelate compound, amino acid, aminocarboxylic acid,
a phenolic compound, aromatic carboxylic acid, sulfonic acid,
ascorbic acid and the like can be exemplified. Carboxylic acid
having a hydroxyl group such as citric acid and gluconic acid,
conventionally known as chelating agents, cannot exert their
function enough in the present invention.
[0050] As the amino acid, a variety of naturally occurring amino
acids and synthetic amino acids, as well as amino acids having at
least one amino group and at least one acid group (carboxyl group,
sulfonic acid group or the like) in one molecule, can be
extensively utilized. Among these, at least one selected from the
group consisting of alanine, glycine, glutamic acid, aspartic acid,
histidine, phenylalanine, asparagine, arginine, glutamine,
cysteine, leucine, lysine, proline, serine, tryptophan, valine and
tyrosine, and a salt thereof can be preferably used. Furthermore,
when there is an optical isomer of the amino acid, any one can be
suitably used irrespective of the forms, i.e., L-form, D-form, or
racemic bodies.
[0051] In addition, as the aminocarboxylic acid, a compound having
both functional groups, an amino group and a carboxyl group in one
molecule other than the amino acid described above can be
extensively used. Among these, at least one selected from the group
consisting of diethylenetriamine pentaacetic acid (DTPA),
hydroxyethylethylenediamine triacetic acid (HEDTA),
triethylenetetraamine hexaacetic acid (TTHA), 1,3-propanediamine
tetraacetic acid (PDTA), 1,3-diamino-6-hydroxypropane tetraacetic
acid (DPTA-OH), hydroxyethylimino diacetic acid (HIDA),
dihydroxyethylglycine (DHEG), glycolether diamine tetraacetic acid
(GEDTA), dicarboxymethyl glutamic acid (CMGA),
(S,S)-ethylenediamine disuccinic acid (EDDS), ethylenediamine
tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and a salt
thereof can be preferably used.
[0052] Furthermore, examples of the phenolic compound include
compounds having two or more phenolic hydroxyl groups, and phenolic
compounds including the same as a basic skeleton. Examples of the
former include catechol, gallic acid, pyrogallol, tannic acid, and
the like. Meanwhile, examples of the latter include flavonoids such
as flavone, isoflavone, flavonol, flavanone, flavanol,
anthocyanidin, aurone, chalcone, epigallocatechin gallate,
gallocatechin, theaflavin, daidzin, genistin, rutin, and
myricitrin, polyphenolic compounds including tannin, catechin and
the like, polyvinylphenol, water soluble resol, novolak resins,
lignin, and the like. Among them, tannin, gallic acid, catechin and
pyrogallol are particularly preferred.
[0053] As the sulfonic acid, at least one selected from the group
consisting of methanesulfonic acid, isethionic acid, taurine,
naphthalenedisulfonic acid, aminonaphthalenedisulfonic acid,
sulfosalicylic acid, a naphthalenesulfonic acid-formaldehyde
condensate, alkylnaphthalenesulfonic acid and the like, and a salt
thereof can be preferably used.
[0054] When sulfonic acid is used, coating performance and
corrosion resistance of the object following the chemical
conversion treatment can be improved. Although the mechanism is not
clarified, the following grounds are conceived.
[0055] First, since there exist silica segregation products and the
like on the surface of the object such as steel plates to yield an
un-uniform surface composition, a portion not susceptible to
etching in the chemical conversion treatment may be present.
However, it is speculated that such a portion not susceptible to
etching can be particularly etched by adding sulfonic acid, and
consequently, a uniform metal oxide film is likely to be formed on
the object surface. In other words, sulfonic acid is believed to
act as an etching accelerator.
[0056] Second, it is possible that in chemical conversion
treatment, hydrogen gas which can be generated by the chemical
conversion reaction inhibits the reaction at the interface, and
sulfonic acid is speculated to remove the hydrogen gas through a
depolarizing action thereby accelerating the reaction.
[0057] Of these, use of taurine is preferred since it has both an
amino group and a sulfone group. The content of sulfonic acid is
preferably in the range of 0.1 to 10,000 ppm, and more preferably
in the range of 1 to 1,000 ppm. When the content is less than 0.1
ppm, the effect is not significantly exhibited, while deposition of
zirconium can be inhibited when the content exceeds 10,000 ppm.
[0058] Use of ascorbic acid leads to uniform formation of the metal
oxide film such as zirconium oxide, tin oxide and the like on the
object surface by the chemical conversion treatment, and the
coating performance and corrosion resistance can be improved.
Although the mechanism is not clarified, the etching action in the
chemical conversion treatment is uniformly executed on the object
such as steel plates, and consequently, it is speculated that
zirconium oxide and/or tin oxide is deposited on the etched part to
form an entirely uniform metal oxide film. In addition, tin is
speculated to become apt to be deposited in the form of the tin
metal at the metal interface due to some influence, and as a
consequence, zirconium oxide is deposited at the part where the tin
metal deposited, whereby surface concealability on the object may
be improved as a whole. The content of ascorbic acid is preferably
in the range of 5 to 5,000 ppm, and more preferably in the range of
20 to 200 ppm. When the content is less than 5 ppm, the effect is
not significantly exhibited, while deposition of zirconium can be
inhibited when the content exceeds 5,000 ppm.
[0059] When the chelating agent is included, its content is
preferably 0.5 to 10 times the concentration of the total
concentration of other metal ions except for zirconium such as tin
ion and copper ion. When the concentration is less than 0.5 times,
the intended effect cannot be exhibited, while a concentration
exceeding 10 times may adversely influence on formation of the
coating film.
[0060] The metal surface treatment liquid for cation
electrodeposition coating of the present invention can further
contain a nitrogenous, sulfur and/or a phenolic rust-preventive
agent. The rust-preventive agent can inhibit corrosion through
forming an anti-corrosion coating film on the metal surface. As the
nitrogenous, sulfurous, phenolic rust-preventive agent, at least
one selected from the group consisting of hydroquinone,
ethyleneurea, quinolinol, thioures, benzotriazole and the like, and
a salt thereof can be used. Use of the nitrogenous, sulfurous,
phenolic rust-preventive agent in the metal surface treatment
liquid for cation electrodeposition coating of the present
invention leads to uniform formation of the metal oxide film such
as zirconium oxide, tin oxide and the like on the object surface by
the chemical conversion treatment, whereby the coating performance,
corrosion resistance can be improved. Although the mechanism is not
clarified, the followings are conceived.
[0061] That is, since there exist silica segregation products and
the like on the steel plate surface to yield an un-uniform surface
composition, a portion having the conversion coating film formed by
etching in the chemical conversion treatment, and a portion without
formation of the conversion coating film due to different etching
behavior thereby having iron oxide may be present. The nitrogenous,
sulfurous, phenolic rust-preventive agent improves primary
rust-preventive properties through adsorbing to the portion without
formation of the conversion coating film in the chemical conversion
treatment to cover the metal interface. It is speculated that the
coating performance, corrosion resistance of the object following
the chemical conversion treatment can be consequently improved.
[0062] In addition, when copper is excessively deposited on the
conversion coating film, this copper may serve as a cathode base
point to form an electrically un-uniform conversion coating film.
However, by allowing the rust-preventive agent to be adsorbed to
the portion where an excessive amount of copper deposited,
improvement of the corrosion resistance is expected to be enabled
by attaining a uniform electrodeposition coating property on the
object following the chemical conversion treatment.
[0063] The content of the nitrogenous, sulfurous and/or phenolic
rust-preventive agent is preferably in the range of 0.1 to 10,000
ppm, and more preferably in the range of 1 to 1,000 ppm. When the
content is less than 0.1 ppm, the effect is not significantly
exhibited, while deposition of zirconium can be inhibited when the
content exceeds 10,000 ppm.
[0064] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may further
contain aluminum ions and/or indium ions. Since these cations have
similar functions to the tin ions, they can be used in combination
when the use of the tin ions alone cannot exhibit the effect. Of
these, aluminum is more preferred. The content of the aluminum ions
and/or the indium ions is preferably in the range of 10 to 1,000
ppm, more preferably in the range of 50 to 500 ppm, and still more
preferably in the range of 100 to 300 ppm. The amount of the
aluminum ions and indium ions can be a concentration accounting
for, for example, 2 to 1,000% of the zirconium ion concentration.
Exemplary metal surface treatment liquids for cation
electrodeposition coating of the present invention include, for
example, the metal surface treatment liquids for cation
electrodeposition coating which contain zirconium ions, tin ions
and aluminum ions. These can further contain fluorine as described
later, and can also contain the polyamine compound described
later.
[0065] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may contain
various cations in addition to the aforementioned components.
Examples of the cation include magnesium, zinc, calcium, gallium,
iron, manganese, nickel, cobalt, silver, and the like. In addition,
there exist cations and anions that are derived from a base or an
acid added for adjusting the pH, or are included as the counter ion
of the aforementioned components.
[0066] The metal surface treatment liquid for cation
electrodeposition coating of the present invention can be produced
by placing each of the components thereof, and/or compound
containing the same into water, followed by mixing.
[0067] Examples of the compound for supplying the zirconium ions
include fluorozirconic acid, salts of fluorozirconic acid such as
potassium fluorozirconate and ammonium fluorozirconate, zirconium
fluoride, zirconium oxide, zirconium oxide colloid, zirconyl
nitrate, zirconium carbonate, and the like.
[0068] Examples of the compound that supplies the tin ions include
tin sulfate, tin acetate, tin fluoride, tin chloride, tin nitrate,
and the like. On the other hand, as the compound that supplies the
fluorine ions, for example, fluorides such as hydrofluoric acid,
ammonium fluoride, fluoboric acid, ammonium hydrogen fluoride,
sodium fluoride, sodium hydrogen fluoride, and the like can be
exemplified.
[0069] Additionally, a complex fluoride can also be used as the
source, and examples thereof include hexafluorosilicic acid salts,
specifically, hydrofluosilicic acid, zinc hydrofluosilicicate,
manganese hydrofluosilicate, magnesium hydrofluosilicate, nickel
hydrofluosilicate, iron hydrofluosilicate, calcium
hydrofluosilicate, and the like. Furthermore, a compound that
supplies zirconium ions, and is a complex fluoride is also
acceptable. Moreover, copper acetate, copper nitrate, copper
sulfate, copper chloride and the like as the compound that supplies
copper ions; aluminum nitrate, aluminum fluoride and the like as
the compound that supplies aluminum ions; and indium nitrate,
indium chloride and the like as the compound that supplies indium
ions can be exemplified, respectively.
[0070] After mixing these components, the metal surface treatment
liquid for cation electrodeposition coating of the present
invention can be regulated to have a predetermined value of pH
using an acidic compound such as nitric acid or sulfuric acid, and
a basic compound such as sodium hydroxide, potassium hydroxide or
ammonia.
[0071] The metal surface treatment liquid for cation
electrodeposition coating of the present invention may contain an
oxidizing agent. The oxidizing agent is particularly preferably at
least one selected from the group consisting of nitric acid,
nitrous acid, hydrogen peroxide, bromic acid, and salts of the
same. The oxidizing agent allows a metal oxide film to be uniformly
formed on the surface of an object, whereby coatability and
corrosion resistance of the object can be improved.
[0072] Although the mechanism is not clarified, it is speculated
that use of the oxidizing agent in a specified amount allows the
etching action in the chemical conversion treatment to be uniformly
executed on an object such as a steel plate, whereby zirconium
oxide and/or tin oxide is deposited at the etched part to form an
entirely uniform metal oxide film. It is also speculated that the
oxidizing agent in the specified amount renders tin readily
deposited as a tin metal at the metal interface, and thus zirconium
oxide is deposited at the portions of deposition of the tin metal,
whereby the surface concealability on the entire object is
improved.
[0073] In order to affect such an action, the content of each
oxidizing agent is as in the following. Accordingly, the content of
nitric acid is preferably in the range of 100 to 100,000 ppm, more
preferably in the range of 1,000 to 20,000 ppm, and still more
preferably in the range of 2,000 to 10,000 ppm. The content of
nitrous acid and bromic acid is preferably in the range of 5 to
5,000 ppm, and more preferably in the range of 20 to 200 ppm. The
content of nitrous acid and bromic acid is preferably in the range
of 5 to 5,000 ppm, and more preferably in the range of 20 to 200
ppm. The content of hydrogen peroxide is preferably in the range of
1 to 1,000 ppm, and more preferably in the range of 5 to 100 ppm.
When content of each is less than the lower limit, the
aforementioned effect is not significantly exhibited, while the
deposition of zirconium can be inhibited when the content exceeds
the upper limit.
[0074] The method of the metal surface treatment of the present
invention includes a step of subjecting a metal base material to a
surface treatment using the metal surface treatment liquid
described above.
[0075] The metal base material is not particularly limited as long
as it can be cation electrodeposited, and for example, an
iron-based metal base material, aluminum-based metal base material,
zinc-based metal base material and the like can be exemplified.
[0076] Examples of the iron-based metal base material include
cold-rolled steel plates, hot-rolled steel plates, soft steel
plates, high-tensile steel plates, and the like. Moreover, examples
of the aluminum-based metal base material include 5,000 series
aluminum alloys, 6,000 series aluminum alloys, and aluminum-coated
steel plates treated by aluminum-based electroplating, hot dipping,
or vapor deposition plating. Furthermore, examples of the
zinc-based metal base material include zinc or zinc-based alloy
coated steel plates treated by zinc-based electroplating, hot
dipping, or vapor deposition plating such as zinc coated steel
plate, zinc-nickel coated steel plate, zinc-titanium coated steel
plate, zinc-magnesium coated steel plate, zinc-manganese coated
steel plate, and the like. There are a variety of grades of the
high-tensile steel plate depending on the strength and manufacture
method, and examples thereof include JSC400J, JSC440P, JSC440W,
JSC590R, JSC590T, JSC590Y, JSC780T, JSC780Y, JSC980Y, JSC1180Y, and
the like.
[0077] Metal base materials including a combination of multiple
kinds of metals such as iron-based, aluminum-based, zinc-based
metals and the like (including joint area and contact area of
different kinds of metals) can be simultaneously applied as the
metal base material.
[0078] The surface treatment step may be carried out by bringing
the metal surface treatment liquid into contact with the metal base
material. Specific examples of the method include a dipping method,
a spraying method, a roll coating method, a pouring method, and the
like.
[0079] The treatment temperature in the surface treatment step
preferably falls within the range of 20 to 70.degree. C. When the
temperature is lower than 20.degree. C., it is possible to cause
failure in formation of a sufficient coating film, while a
corresponding effect cannot be expected at a temperature above
70.degree. C. The lower limit and the upper limit are more
preferably 30.degree. C. and 50.degree. C., respectively.
[0080] The treatment time period in the surface treatment step is
preferably 2 to 1100 seconds. When the time period is less than 2
seconds, a sufficient coating film amount may not be attained,
while a corresponding effect cannot be expected even though it is
longer than 1100 seconds. The lower limit and the upper limit are
still more preferably 30 seconds and 120 seconds, respectively.
Accordingly, a coating film is formed on the metal base
material.
[0081] The surface treated metal base material of the present
invention is obtained by the surface treatment method described
above. On the surface of the metal base material is formed a
coating film that contains zirconium and tin. The element ratio of
zirconium/tin in the coating film is preferably in the range of
1/10 to 10/1 on a mass basis. When the ratio is out of this range,
the intended performance may not be attained.
[0082] The content of zirconium in the coating film is preferably
no less than 10 mg/m.sup.2 in the case of iron-based metal base
materials. When the content is less than 10 mg/m.sup.2, sufficient
anti-corrosion properties may not be achieved. The content is more
preferably no less than 20 mg/m.sup.2, and still more preferably no
less than 30 mg/m.sup.2. Although the upper limit is not
specifically defined, too large an amount of the coating film may
lead to an increased likelihood of crack generation of the
rust-preventive coating film, and may make it difficult to obtain a
uniform coating film. In this respect, the content of zirconium in
the coating film is preferably no greater than 1 g/m.sup.2, and
more preferably no greater than 800 mg/m.sup.2.
[0083] When the coating film is formed using the metal surface
treatment liquid which contains copper ions, the content of copper
in the coating film is preferably no less than 0.5 mg/m.sup.2 in
order to achieve the intended effect.
[0084] The method of cation electrodeposition coating of the
present invention includes a step of subjecting a metal base
material to a surface treatment using the metal surface treatment
liquid described above, and a step of subjecting the surface
treated metal base material to cation electrodeposition
coating.
[0085] The surface treatment step in the aforementioned cation
electrodeposition coating is same as the surface treatment step in
the surface treatment method described above. The surface treated
metal base material obtained in the surface treatment step may be
subjected to the cation electrodeposition coating step directly or
after washing.
[0086] In the cation electrodeposition coating step, the surface
treated metal base material is subjected to the cation
electrodeposition coating. In the cation electrodeposition coating,
the surface treated metal base material is dipped in cation
electrodeposition coating solution, and a voltage of 50 to 450 V is
applied thereto using the same as a cathode for a certain period of
time. Although the application time period of voltage may vary
depending on the conditions of the electrodeposition, it is
generally 2 to 4 minutes.
[0087] As the cation electrodeposition coating solution, a
generally well known one can be used. Specifically, such general
coating solutions are prepared by blending: a binder cationized
through adding amine or sulfide to an epoxy group carried by an
epoxy resin or an acrylic resin, followed by adding thereto a
neutralizing acid such as acetic acid; block isocyanate as a curing
agent; and a pigment dispersing paste including a rust-preventive
pigment dispersed in a resin.
[0088] After completing the cation electrodeposition coating step,
a hardened coated film can be obtained by baking at a predetermined
temperature directly, or after washing with water. Although the
baking conditions may vary depending on the type of the cation
electrodeposition coating solution used, usually the baking may be
conducted in the range of 120 to 260.degree. C., and preferably in
the range of 140 to 220.degree. C. The baking time period can be 10
to 30 minutes. The resulting metal base material coated by the
cation electrodeposition is also involved as an aspect of the
present invention.
EXAMPLES
Production Example 1
Production of Hydrolysis Condensate of Aminosilane, Part 1
[0089] As aminosilane, 5 parts by mass of KBE603
(3-aminopropyl-triethoxysilane, effective concentration: 100%,
manufactured by Shin-Etsu Chemical Co., Ltd.) was added dropwise
using a dropping funnel to a mixed solvent (solvent temperature:
25.degree. C.) containing 47.5 parts by mass of deionized water and
47.5 parts by mass of isopropyl alcohol over 60 minutes to a
homogenous state, followed by allowing for reaction under a
nitrogen atmosphere at 25.degree. C. for 24 hours. Then, the
reaction solution was subjected to a reduced pressure to allow for
evaporation of isopropyl alcohol, and deionized water was further
added thereto, whereby a hydrolysis condensate of aminosilane
including 5% of the active ingredient was obtained.
Production Example 2
Production of Hydrolysis Condensate of Aminosilane, Part 2
[0090] In a similar manner to Production Example 1, except that the
amounts were changed to 20 parts by mass of KBE603, 40 parts by
mass of deionized water, and 40 parts by mass of isopropyl alcohol,
a hydrolysis condensate of aminosilane including 20% of the active
ingredient was obtained.
Example 1
[0091] A metal surface treatment liquid for cation
electrodeposition coating was obtained by: mixing a 40% aqueous
zircon acid solution as a zirconium ion source, tin sulfate as a
tin ion source, and hydrofluoric acid; diluting the mixture so as
to give a zirconium ion concentration of 500 ppm, and a tin ion
concentration of 30 ppm; and adjusting the pH to 3.5 using nitric
acid and sodium hydroxide. Measurement of free fluorine ion
concentration using a fluorine ion meter after adjusting the pH of
this treatment liquid to 3.0 revealed a value of 5 ppm.
Example 2
[0092] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 1 except that: the hydrolysis condensate of aminosilane
obtained in Production Example 1 was further added to be 200 ppm;
tin sulfate was changed to tin acetate so as to give the tin ion
concentration of 10 ppm; and the pH was adjusted to 2.75.
Measurement of the free fluorine ion concentration using a fluorine
ion meter after adjusting the pH of this treatment liquid to 3.0
revealed a value of 5 ppm.
Example 3
[0093] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 1 except that: polyallylamine "PAA-H-10C" (trade name,
manufactured by Nitto Boseki Co., Ltd.) was further added to be 25
ppm; zirconium ion concentration was changed to 250 ppm; and the pH
was adjusted to 3.0. Measurement of the free fluorine ion
concentration using a fluorine ion meter on this treatment liquid
revealed a value of 5 ppm.
Example 4
[0094] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 1, except that: copper nitrate was further added so as to
give a copper ion concentration of 10 ppm; the tin ion
concentration was changed to 10 ppm; and the pH was adjusted to
3.0. Measurement of the free fluorine ion concentration using a
fluorine ion meter on this treatment liquid revealed a value of 5
ppm.
Example 5
[0095] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 4, except that: the hydrolysis condensate of aminosilane
obtained in Production Example 2 was further added to be 200 ppm;
and the tin ion concentration was changed to 30 ppm. Measurement of
the free fluorine ion concentration using a fluorine ion meter on
this treatment liquid revealed a value of 5 ppm.
Example 6
[0096] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 2, except that: aluminum nitrate was further added so as to
give an aluminum ion concentration of 200 ppm; and tin sulfate was
changed to tin acetate so as to give the tin ion concentration of
30 ppm. Measurement of the free fluorine ion concentration using a
fluorine ion meter after adjusting the pH of this treatment liquid
to 3.0 revealed a value of 5 ppm.
Examples 7 and 8
[0097] Metal surface treatment liquids for cation electrodeposition
coating were obtained in a similar manner to Example 6, except that
the pH was adjusted to 3.5 and 4.0. The free fluorine ion
concentration measured using a fluorine ion meter after adjusting
the pH of this treatment liquid to 3.0 is shown in Table 1.
Examples 9 to 16
[0098] Metal surface treatment liquids for cation electrodeposition
coating were obtained in a similar manner to Example 7, except that
the amount of added 40% aqueous zirconic acid solution, tin
sulfate, and aluminum nitrate was changed so as to give a zirconium
ion concentration, a tin ion concentration, and an aluminum ion
concentration as shown in Table 1. The free fluorine ion
concentration measured using a fluorine ion meter after adjusting
the pH of this treatment liquid to 3.0 is shown in Table 1.
Example 17
[0099] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 2, except that: indium nitrate was further added so as to
give an indium ion concentration of 200 ppm; tin sulfate was
changed to tin fluoride so as to give a tin ion concentration of 30
ppm; and the pH was adjusted to 3.5. Measurement of the free
fluorine ion concentration using a fluorine ion meter after
adjusting the pH of this treatment liquid to 3.0 revealed a value
of 5 ppm.
Example 18
[0100] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 2, except that: diethylenetriamine pentaacetic acid (DTPA)
was further added as a chelating agent to give a concentration of
100 ppm; tin acetate was changed to tin sulfate, thereby changing
the tin ion concentration to 30 ppm; and further, the zirconium ion
concentration was changed to 1,000 ppm. Measurement of the free
fluorine ion concentration using a fluorine ion meter after
adjusting the pH of this treatment liquid to 3.0 revealed a value
of 10 ppm.
Example 19
[0101] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 2, except that: sodium nitrate was further added so as to
give a sodium ion concentration of 5,000 ppm; and the tin ion
concentration was changed to 30 ppm. Measurement of the free
fluorine ion concentration using a fluorine ion meter after
adjusting the pH of this treatment liquid to) 3.0 revealed a value
of 5 ppm.
Example 20
[0102] A metal surface treatment liquid for cation
electrodeposition coating was obtained in a similar manner to
Example 5, except that: glycine as chelating agents and copper
nitrate further added so as to give a concentration of 50 ppm and
copper ion concentration of 10 ppm, respectively; and the
concentration of polyamine was changed to 100 ppm. Measurement of
the free fluorine ion concentration using a fluorine ion meter on
this treatment liquid revealed a value of 5 ppm.
Examples 21 to 31
[0103] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: polyamine as described in Table 1 was added in a
specified amount; and the concentration of the other component was
changed as shown in Table 1. The free fluorine ion concentrations
measured using a fluorine ion meter on these treatment liquids
under a condition of pH 3.0 are shown together in Table 1.
Examples 32 to 50
[0104] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: sulfonic acid described in Table 2 was added in a
specified amount; and polyamine and the other component were
changed as shown in Table 2. The free fluorine ion concentrations
measured using a fluorine ion meter on these treatment liquids
under a condition of pH 3.0 are shown together in Table 2. In Table
2, the used naphthalenesulfonic acid-formaldehyde condensate was
DEMOL NL manufactured by Kao Corporation; sodium
alkylnaphthalenesulfonate was PELEX NBL manufactured by Kao
Corporation; and sodium polystyrenesulfonate was P-NASS-1
manufactured by Tosoh Corporation.
Examples 51
[0105] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: ascorbic acid as described in Table 3 was added in
a specified amount; and polyamine and the other component were
changed as shown in Table 3. The free fluorine ion concentrations
measured using a fluorine ion meter on these treatment liquids
under a condition of pH 3.0 are shown together in Table 3.
Examples 52 to 59
[0106] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: the oxidizing agent described in Table 3 was added
in a specified amount; and polyamine and the other component were
changed as shown in Table 3. The free fluorine ion concentrations
measured using a fluorine ion meter on these treatment liquids
under a condition of pH 3.0 are shown together in Table 3.
Examples 60 to 74
[0107] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: the nitrogen-based rust-preventive agent, the
sulfur-based rust-preventive agent, or the phenol-based
rust-preventive agent described in Table 3 was added in a specified
amount; and polyamine and the other component were changed as shown
in Table 3. The free fluorine ion concentrations measured using a
fluorine ion meter on these treatment liquids under a condition of
pH 3.0 are shown together in Table 3.
Examples 75 to 77
[0108] Metal surface treatment liquids for cation electrodeposition
coating were respectively obtained in a similar manner to Example
1, except that: instead of a cold-rolled steel plate (SPC) a
high-tensile steel plate was used as the base plate that is the
object; and polyamine and the other component described in Table 3
were changed as shown in Table 3. The free fluorine ion
concentrations measured using a fluorine ion meter on these
treatment liquids under a condition of pH 3.0 are shown together in
Table 3.
Examples 78 to 106
[0109] With respect to Examples 2, 3, and 5 to 31, metal surface
treatment liquids for cation electrodeposition coating were
obtained in a similar manner to each Example, except that polyamine
was not added. The free fluorine ion concentrations measured using
a fluorine ion meter after adjusting the pH of the treatment
liquids to 3.0 are shown in Table 4.
Comparative Examples 1 to 6
Preparation of Comparative Metal Surface Treatment Liquid
[0110] According to the description in Table 1 and Table 3,
comparative metal surface treatment liquids were obtained,
respectively, based on the aforementioned Examples. Thus resulting
metal surface treatment liquids are summarized in Table 1 and Table
3.
TABLE-US-00001 TABLE 1 Added Component Zr Tin ion Sn (Concentraion
in Parenthesis (ppm)) Free Fluorine Concentration supplying
Concentration Sn/Zr Polyamine ion (ppm) compound (ppm) ratio pH
Compound Others Concentration Example 1 500 tin sulfate 30 0.06 3.5
absent 5 Example 2 500 tin sulfate 10 0.02 2.75 Production 5
Exapmle 1 (200) Example 3 250 tin sulfate 30 0.12 3 poly 5
allylamine (25) Example 4 500 tin sulfate 10 0.02 3 absent copper
nitrate (10) 5 Example 5 500 tin sulfate 30 0.06 3 Production
copper nitrate (10) 5 Exapmle 2 (200) Example 6 500 tin acetate 30
0.06 2.75 Production aluminum nitrate (200) 5 Exapmle 1 (200)
Example 7 500 tin acetate 30 0.06 3.5 Production aluminum nitrate
(200) 5 Exapmle 1 (200) aluminum nitrate (200) 5 Example 8 500 tin
acetate 30 0.06 4 Production aluminum nitrate (200) 7 Exapmle 1
(200) Example 9 1000 tin acetate 30 0.03 3.5 Production aluminum
nitrate (200) 7 Exapmle 1 (200) Example 10 500 tin acetate 30 0.06
3.5 Production aluminum nitrate (500) 5 Exapmle 1 (200) Example 11
500 tin acetate 30 0.06 3.5 Production aluminum 5 Exapmle 1 (200)
nitrate (1000) Example 12 500 tin acetate 10 0.02 3.5 Production
aluminum nitrate (500) 5 Exapmle 1 (200) Example 13 500 tin acetate
200 0.4 3.5 Production aluminum nitrate (500) 5 Exapmle 1 (200)
Example 14 200 tin acetate 10 0.05 3.5 Production aluminum nitrate
(200) 7 Exapmle 1 (200) Example 15 200 tin acetate 30 0.15 3.5
Production aluminum nitrate (200) 5 Exapmle 1 (200) Example 16 200
tin acetate 70 0.35 3.5 Production aluminum nitrate (200) 5 Exapmle
1 (200) Example 17 500 tin 30 0.06 3.5 Production indium nitrate
(50) 5 fluoride Exapmle 1 (200) Example 18 1000 tin sulfate 30 0.03
2.75 Production DTPA (100) 10 Exapmle 1 (200) Example 19 500 tin
sulfate 30 0.06 2.75 Production sodium nitrate (5000) 5 Exapmle 1
(200) Example 20 500 tin sulfate 30 0.06 3 Production coppoer
sulfate (10), 5 Exapmle 2 (100) glycine (50) Example 21 20 tin
sulfate 5 0.25 3 Production Exapmle 2 1 (10) Example 22 500 tin
sulfate 20 0.04 2 Production Exapmle 1 1 (200) Example 23 500 tin
sulfate 30 0.06 5.5 Production Exapmle 20 1 (200) Example 24 5000
tin sulfate 25 0.005 3 Production Exapmle 10 1 (2000) Example 25 50
tin sulfate 10 0.2 3 Production Exapmle 3 2 (50) Example 26 50 tin
sulfate 50 1 3 Production Exapmle 1 2 (25) Example 27 500 tin
sulfate 30 0.06 3 Production Exapmle 0 1 (50) Example 28 500 tin
sulfate 30 0.06 2.75 Production Exapmle 0.1 2 (50) Example 29 500
tin sulfate 30 0.06 2.75 Production Exapmle 0.6 2 (50) Example 30
500 tin sulfate 30 0.06 4 Production Exapmle 20 1 (200) Example 31
500 tin sulfate 30 0.06 4.5 Production Exapmle 50 1 (200)
Comparative 500 absent 0 0 3.5 Production Exapmle 7 Example 1 1
(200) Comparative 500 absent 0 0 3 Production Exapmle aluminum
nitrate (500) 5 Example 2 1 (200) Comparative 50 absent 0 0 3.5
Production Exapmle 5 Example 3 1 (200) Comparative 500 tin sulfate
250 0.5 1 Production Exapmle 5 Example 4 1 (200) Comparative 500
tin sulfate 250 0.5 8 Production Exapmle 5 Example 5 1 (200)
TABLE-US-00002 TABLE 2 Added Component Zr Tin ion Sn (Concentraion
in Parenthesis (ppm)) Concentration supplying Concentration
Polyamine Free Fluorine ion (ppm) compounds (ppm) Sn/Zr ratio pH
Compound Other Metal Others Concentration Example 500 tin sulfate
30 0.06 3.5 Production taurine (100) 5 32 Exapmple 1 (200) Example
500 tin sulfate 30 0.06 3.5 Production methan sulfonic 5 33
Exapmple acid (100) 1 (200) Example 500 tin sulfate 30 0.06 3.5
Production isethionic 5 34 Exapmple acid (100) 1 (200) Example 500
tin sulfate 30 0.06 3.5 Production sodium 5 35 Exapmple
naphthalenedisulfonate 1 (200) (100) Example 500 tin sulfate 30
0.06 3.5 Production sodium 5 36 Exapmple aminonaphthalene 1 (200)
disulfonate (100) Example 500 tin sulfate 30 0.06 3.5 Production
sulfosalicylic 5 37 Exapmple acid (100) 1 (200) Example 500 tin
sulfate 30 0.06 3.5 Production naphthalene 5 38 Exapmple sulfonic
acid- 1 (200) formaldehyde condensate (100) Example 500 tin sulfate
30 0.06 3.5 Production sodium 5 39 Exapmple alkylnaphthalene 1
(200) sulfonate (100) Example 500 tin sulfate 30 0.06 3.5
Production copper taurine (100) 5 40 Exapmple nitrate (10) 1 (200)
Example 500 tin sulfate 30 0.06 3.5 -- copper taurine (100) 5 41
nitrate (10) Example 500 tin sulfate 30 0.06 3.5 -- aluminum methan
sulfonic 5 42 nitrate (200) acid (100) Example 500 tin sulfate 30
0.06 3.5 -- copper isethionic 5 43 nitrate (10) acid (100) Example
500 tin sulfate 30 0.06 3.5 -- aluminum sodium 5 44 nitrate
naphthalenedisulfonate (200) (100) Example 500 tin sulfate 30 0.06
3.5 -- copper sodium 5 45 nitrate (10) aminonaphthalene disulfonate
(100) Example 500 tin sulfate 30 0.06 3.5 -- aluminum
sulfosalicylic 5 46 nitrate acid (100) (200) Example 500 tin
sulfate 30 0.06 3.5 -- copper naphthalene 5 47 nitrate (10)
sulfonic acid- formaldehyde condensate (100) Example 500 tin
sulfate 30 0.06 3.5 -- aluminum sodium 5 48 nitrate
alkylnaphthalene (200) sulfonate (100) Example 500 tin sulfate 30
0.06 3.5 -- copper sodium 5 49 nitrate (10) styrenesulfonate (100)
Example 500 tin sulfate 30 0.06 3.5 -- aluminum sodium 5 50 nitrate
polystyrene (200) sulfonate (100)
TABLE-US-00003 TABLE 3 Added Component (Concentration in Zr Tin ion
Sn Parenthesis (ppm)) Concentration Supplying Concentration
Polyamine Other Free Fluorine ion (ppm) Compounds (ppm) Sn/Zr ratio
pH Compounds Metal Others Concentration Example 51 500 tin 30 0.06
3.5 Production -- sodium 5 sulfate Example ascorbate 1 (200) (50)
Example 52 500 tin 30 0.06 3.5 Production -- as sodium 5 sulfate
Example nitrate 1 (200) (10000) Example 53 500 tin 30 0.06 3.5
Production -- hydrogen 5 sulfate Example peroxide (10) 1 (200)
Example 54 500 tin 30 0.06 3.5 Production -- sodium 5 sulfate
Example nitrite (50) 1 (200) Example 55 500 tin 30 0.06 3.5
Production -- sodium 5 sulfate Example bromate (100) 1 (200)
Example 56 500 tin 30 0.06 3.5 -- copper as sodium 5 sulfate
nitrate (10) nitrate (10000) Example 57 500 tin 30 0.06 3.5 --
aluminum hydrogen 5 sulfate nitrate peroxide (10) (200) Example 58
500 tin 30 0.06 3.5 -- copper sodium 5 sulfate nitrate (10) nitrite
(50) Example 59 500 tin 30 0.06 3.5 -- aluminum sodium 5 sulfate
nitrate bromate (100) (200) Example 60 500 tin 30 0.06 3.5
Production -- hydroquinone 5 sulfate Example (100) 1 (200) Example
61 500 tin 30 0.06 3.5 Production -- ethylene 5 sulfate Example
urea (100) 1 (200) Example 62 500 tin 30 0.06 3.5 Production --
quinolinol (100) 5 sulfate Example 1 (200) Example 63 500 tin 30
0.06 3.5 Production -- thiourea (100) 5 sulfate Example 1 (200)
Example 64 500 tin 30 0.06 3.5 Production -- benzotriazole 5
sulfate Example (100) 1 (200) Example 65 500 tin 30 0.06 3.5
Production -- mercaptobenzothiazole 5 sulfate Example (100) 1 (200)
Example 66 500 tin 30 0.06 3.5 Production -- KBM803 (100) 5 sulfate
Example 1 (200) Example 67 500 tin 30 0.06 3.5 Production copper
benzotriazole 5 sulfate Example nitrate (10) (100) 1 (200) Example
68 500 tin 30 0.06 3.5 -- copper hydroquinone 5 sulfate nitrate
(10) (100) Example 69 500 tin sulfate 30 0.06 3.5 -- copper
ethylene urea (100) 5 nitrate (10) Example 70 500 tin sulfate 30
0.06 3.5 -- copper quinolinol (100) 5 nitrate (10) Example 71 500
tin sulfate 30 0.06 3.5 -- copper thiourea (100) 5 nitrate (10)
Example 72 500 tin sulfate 30 0.06 3.5 -- copper benzotriazole
(100) 5 nitrate (10) Example 73 500 tin sulfate 30 0.06 3.5 --
copper mercaptobenzothiazole 5 nitrate (10) (100) Example 74 500
tin sulfate 30 0.06 3.5 -- copper KBM803 (100) 5 nitrate (10)
Example 75 500 tin sulfate 30 0.06 3.5 Production copper as sodium
nitrate 5 Example nitrate (10) (10000) 1 (200) Example 76 500 tin
sulfate 30 0.06 3.5 Production copper taurine (100) 5 Example
nitrate (10) 1 (200) Example 77 500 tin sulfate 30 0.06 3.5
Production copper benzotriazole (100) 5 Example nitrate (10) 1
(200) Comparative 500 -- -- -- 3.5 Production -- 5 Example 6
Example 1 (200)
TABLE-US-00004 TABLE 4 Added Component (Concentration in Zr Tin ion
Sn Parenthesis (ppm)) Free Fluorine Concentration Supplying
Concentration Sn/Zr Polyamine ion (ppm) Compounds (ppm) ratio pH
Compounds Others Concentration Example 78 500 tin sulfate 10 0.02
2.75 -- 5 Example 79 250 tin sulfate 30 0.12 3 -- 5 Example 80 500
tin sulfate 30 0.06 3 -- copper 5 nitrate (10) Example 81 500 tin
sulfate 30 0.06 2.75 -- aluminum 5 nitarte (200) Example 82 500 tin
acetate 30 0.06 3.5 -- aluminum 5 nitarte (200) Example 83 500 tin
acetate 30 0.06 4 -- aluminum 5 nitarte (200) Example 84 1000 tin
acetate 30 0.03 3.5 -- aluminum 7 nitarte (200) Example 85 500 tin
acetate 30 0.06 3.5 -- aluminum 5 nitrate (500) Example 86 500 tin
acetate 30 0.06 3.5 -- aluminum 5 nitrate (1000) Example 87 500 tin
acetate 10 0.02 3.5 -- aluminum 5 nitrate (500) Example 88 500 tin
acetate 200 0.4 3.5 -- aluminum 5 nitrate (500) Example 89 200 tin
acetate 10 0.05 3.5 -- aluminum 7 nitarte (200) Example 90 200 tin
acetate 30 0.15 3.5 -- aluminum 5 nitarte (200) Example 91 200 tin
acetate 70 0.35 3.5 -- aluminum 5 nitarte (200) Example 92 500 tin
fluoride 30 0.06 3.5 -- indium 5 nitrate (50) Example 93 1000 tin
sulfate 30 0.03 2.75 -- DTPA (100) 10 Example 94 500 tin sulfate 30
0.06 2.75 -- sodium 5 nitrate (5000) Example 95 500 tin sulfate 30
0.06 3 -- copper 5 nitrate (10), glycine (50) Example 96 20 tin
sulfate 5 0.25 3 -- 2 Example 97 500 tin sulfate 20 0.04 2 -- 1
Example 98 500 tin sulfate 30 0.06 5.5 -- 20 Example 99 5000 tin
sulfate 25 0.005 3 -- 10 Example 50 tin sulfate 10 0.2 3 -- 3 100
Example 50 tin sulfate 50 1 3 -- 1 101 Example 500 tin sulfate 30
0.06 3 -- 0 102 Example 500 tin sulfate 30 0.06 2.75 -- 0.1 103
Example 500 tin sulfate 30 0.06 2.75 -- 0.6 104 Example 500 tin
sulfate 30 0.06 4 -- 20 105 Example 500 tin sulfate 30 0.06 4.5 --
50 106
Surface Treatment
[0111] As metal base materials, a commercially available
cold-rolled steel plate (SPC, manufactured by Nippon Testpanel Co.,
Ltd., 70 mm.times.150 mm.times.0.8 mm) was provided for Examples 1
to 74, Examples 78 to 106, and Comparative Examples 1 to 5, and a
high-tensile steel plate (70 mm.times.150 mm.times.1.0 mm) was
provided for Examples 75 to 77, and Comparative Example 6. These
plates were subjected to a degreasing treatment using "SURFCLEANER
EC92" (trade name, manufactured by Nippon Paint Co., Ltd.) as an
alkali degreasing treatment agent at 40.degree. C. for 2 minutes.
This plate was dipped and washed in a water washing bath, and then
washed by spraying tap water thereon for approximately 30
seconds.
[0112] The metal base material following the degreasing treatment
was subjected to a surface treatment by dipping thereof in the
metal surface treatment liquid prepared in Examples and Comparative
Examples at 40.degree. C. for 90 seconds. However, the treatment
time period was 240 seconds and 15 seconds, respectively, in
Examples 21 and 22. After completing the surface treatment, the
plate was dried at 40.degree. C. for 5 minutes, and the thus
surface treated metal base material was obtained. Unless
specifically stated, this surface treated metal base material was
used as a test plate in the following evaluation.
Measurement of Element Content in Coating Film
[0113] The content of each element included in the coating film was
measured using an X-ray fluorescence spectrometer "XRF1700"
manufactured by Shimadzu Corporation.
Primary Rust Prevention
[0114] After immersing the test plate in pure water at 25.degree.
C. for 5 hours, the generation state of rust was visually
observed.
A: no rust generation observed B: slightly generated rust observed
C: rust generation clearly identified
Observation of Sludge
[0115] With 10 L of the surface treatment liquids of the Examples
and Comparative Examples, 200 test panels were subjected to the
surface treatment and evaluation was made according to the
following standards through visual observation as to whether the
surface treatment liquid became turbid due to generation of sludge
following the lapse of 30 days at room temperature.
A: transparent liquid B: slightly turbid C: turbid D: precipitate
(sludge) generated
Evaluation of Throwing Power
[0116] The throwing power was evaluated according to a "four-plate
box method" described in Japanese Unexamined Patent Application,
First Publication No. 2000-038525. More specifically, as shown in
FIG. 1, test plates 1 to 4 were arranged to stand up in parallel
with intervals of 20 mm to produce a box 10 sealed with an
insulator such as cloth adhesive tape at the underneath of both
side faces and the bottom face. Through-holes 5 having a diameter
of 8 mm were provided underneath the metal materials 1, 2 and 3,
except for metal material 4.
[0117] This box 10 was dipped into an electrodeposition coating
vessel 20 filled with a cation electrodeposition coating solution
"POWERNICS 110" (trade name, manufactured by Nippon Paint Co.,
Ltd.). In this case, the cation electrodeposition coating solution
entered inside the box 10 only from each through-hole 5.
[0118] Each of the test plates 1 to 4 was electrically connected
while stirring the cation electrodeposition coating solution with a
magnetic stirrer, and a counter electrode 21 was arranged such that
the distance from the test plate 1 became 150 mm. Voltage was
applied with each of the test plates 1 to 4 as cathodes, and the
counter electrode 21 as an anode to execute cation
electrodeposition coating. The coating was carried out by elevating
to the intended voltage (210 V and 160 V) over 30 seconds from
initiation of the application, and thereafter maintaining the
voltage for 150 seconds. The bath temperature in this process was
regulated to 30.degree. C.
[0119] After washing each of the test plates 1 to 4 with water
after coating, they were baked at 170.degree. C. for 25 minutes,
followed by air cooling. The throwing power was then evaluated by
measuring the film thickness of the coated film formed on side A of
the test plate 1 that is the closest to the counter electrode 21,
and the film thickness of the coated film formed on side G of the
test plate 4 that is the farthest from the counter electrode 21 to
determine a ratio of the film thickness (side G)/film thickness
(side A). As this value becomes greater, better evaluation of the
throwing power can be decided. The acceptable level was no less
than 40%.
Coating Voltage
[0120] Using the surface treatment liquids of Examples and
Comparative Examples, cold-rolled steel plates and zinc coated
steel plates were subjected to a surface treatment, whereby test
plates were obtained. Using the cation electrodeposition coating
solution "POWERNICS 110" described above on these test plates, the
voltage required for obtaining a 20 .mu.m electrodeposition coated
film was determined. The difference in coating voltage required for
obtaining the 20 .mu.m electrodeposition coated film was then
determined between the case in which the metal base material was a
zinc coated steel plate, and the case of the cold-rolled steel
plate. As the difference becomes smaller, superiority as a surface
treated coating film is suggested. A difference of no greater than
40 V is acceptable.
[0121] The voltage required for obtaining a 20 .mu.m
electrodeposition coated film was determined as in the following
manner. Under the electrodeposition condition, the voltage was
elevated to a specified voltage over 30 seconds, and thereafter
maintaining for 150 seconds. The resulting film thickness was
measured. Such a procedure was conducted for 150 V, 200 V, and 250
V. Thus, a voltage to give a 20 .mu.m film thickness was derived
from the formula of relationship between the determined voltage and
the film thickness.
Appearance of Coating
[0122] The test plate was subjected to cation electrodeposition
coating, and the appearance of the resulting electrodeposition
coated film was evaluated according to the following standards. The
results are shown in Tables 5 to 8.
A: uniform coated film obtained B: nearly uniform coated film
obtained C: some non-uniformity of the coated film found D:
non-uniformity of the coated film found
Secondary Adhesion Test (SDT)
[0123] After forming a 20 .mu.m electrodeposition coated film, the
test plates were incised to provide two parallel cut lines that ran
longitudinally, with the depth to reach to the metal basis
material, and then immersed in a 5% aqueous sodium chloride
solution at 55.degree. C. for 240 hours. After water washing and
air drying, an adhesive tape "L-PACK LP-24" (trade name,
manufactured by Nichiban Co., Ltd.) was adhered to the portion
including the cuts. Then, the adhesive tape was peeled off
abruptly. The maximum width (one side) of the coating adhered to
the stripped adhesive tape was measured.
A: 0 mm
[0124] B: less than 2 mm C: at least 2 mm to less than 5 mm D: no
less than 5 mm
Cycle Corrosion Test (CCT)
[0125] After forming the 20 .mu.m electrodeposition coated film on
the test plate, the edge and back face was sealed with a tape,
thereby providing cross cuttings that reached to the metal basis
material. A 5% aqueous sodium chloride solution incubated at
35.degree. C. was continuously sprayed for 2 hours onto this sample
in a salt spray tester kept at 35.degree. C., and with a humidity
of 95%. Subsequently, it was dried under conditions of 60.degree.
C. and with a humidity of 20 to 30% for 4 hours. Such a sequence of
procedures repeated three times in 24 hours was defined as one
cycle, and 200 cycles were carried out. Thereafter, the width of
the swelling portion of the coated film (both sides) was
measured.
A: less than 6 mm B: at least 6 mm to less than 8 mm C: at least 8
mm to less than 10 mm D: no less than 10 mm
Salt Spray Test (SST)
[0126] After forming the 20 .mu.m electrodeposition coated film on
the test plate, the edge and the back face were sealed with a tape,
thereby providing cross cuttings that reached to the metal basis
material. A 5% aqueous sodium chloride solution incubated at
35.degree. C. was continuously sprayed for 840 hours to this sample
in a salt spray tester kept at 35.degree. C., and with a humidity
of 95%. After washing with water and air drying, an adhesive tape
"L-PACK LP-24" (trade name, manufactured by Nichiban Co., Ltd.) was
adhered on the portion including the cuts. Then, the adhesive tape
was peeled off quickly. The maximum width (one side) of the coating
adhered to the stripped adhesive tape was measured.
A: less than 2 mm B: at least 2 mm to less than 5 mm C: no less
than 5 mm
[0127] The evaluation results are summarized in Tables 5 to 8.
TABLE-US-00005 TABLE 5 Content Primary Throwing Difference
Appearance of Element Rust Observation Power (%) in Coating of Zr
Si Sn Cu Prevention of sludge 210 V 160 V Voltage (V) Coating SDT
CCT SST Example 1 45 22 A B 60% 52% 30 A -- B A Example 2 51 3.3 13
A B 57% 25% 40 B A B A Example 3 44 24 A B 57% 44% 40 A B B A
Example 4 55 16 8 A B 58% 51% 40 A A A A Example 5 46 6.2 27 11 A B
61% 55% 20 A A A A Example 6 42 3.5 19 A B 57% 47% 40 A A B A
Example 7 56 3.7 15 -- A B 53% 42% 30 B A B A Example 8 62 4.1 12
-- A C 51% 39% 30 B A B A Example 9 41 2.3 16 -- A B 53% 41% 30 B B
B A Example 10 72 2.4 15 -- A C 54% 43% 30 B A B A Example 11 62
2.4 15 -- A C 53% 43% 30 B B B A Example 12 75 3.2 10 -- A C 49%
40% 30 B A A A Example 13 32 2.1 31 -- A B 59% 51% 20 B B B A
Example 14 52 2.5 12 -- A B 58% 30% 40 B A B A Example 15 38 2.3 18
A B 59% 48% 20 B B B A Example 16 31 2.1 23 A B 62% 50% 20 B B B A
Example 17 55 3 22 A B 59% 50% 20 A A B A Example 18 51 3.3 19 A A
56% 51% 30 A B B A Example 19 44 2.5 23 A B 56% 49% 30 A A B A
Example 20 48 4.8 22 6 A A 58% 52% 20 A B A A Example 21 28 1.8 21
A B 52% 44% 30 B B B A Example 22 63 4.2 28 A B 55% 49% 30 B B B A
Example 23 44 2.9 26 A B 60% 43% 30 B B B A Example 24 77 5.1 31 A
B 52% 52% 20 B A A A Example 25 34 2.6 26 A B 51% 41% 30 B B B A
Example 26 42 2.6 27 A B 62% 48% 20 B B B A Example 27 38 2.7 18 A
B 52% 29% 40 B B B A Example 28 38 3.5 21 A B 53% 36% 30 B B B A
Example 29 41 3 26 A B 55% 42% 30 B B B A Example 30 44 3 22 A B
58% 41% 30 B A A A Example 31 47 3.5 25 A B 57% 48% 20 B A A A
Comparative 52 3.5 B B 21% 12% 80 C B C A Example 1 Comparative 55
3.3 B B 36% 15% 50 B D C B Example 2 Comparative 5.2 0.1 38 A B 60%
55% 30 B D D C Example 3 Comparative 1.2 0.1 0.2 C D 57% 45% 30 B D
D C Example 4 Comparative 0 0 0 C -- 38% -- -- B D D C Example
5
TABLE-US-00006 TABLE 6 Content Primary Throwing Difference of
Element Rust Observation Power (%) in Coating Appearance Zr Si Sn
Cu Prevention of sludge 210 V 160 V Voltage (V) of Coating SDT CCT
SST Example 32 42 3.2 18 A B 6900% 6100% 10 A A A A Example 33 45
3.3 16 A B 6200% 5700% 20 A A A A Example 34 41 3 15 A B 6200%
5500% 20 A A A A Example 35 38 2.9 16 A B 6400% 5100% 30 A A A A
Example 36 44 3.1 19 A B 6100% 5300% 30 A A A A Example 37 51 3.6
21 A B 5900% 5200% 30 A A A A Example 38 48 3.5 16 A B 6000% 4700%
30 A A A A Example 39 42 32 22 A B 6000% 4600% 20 A A A A Example
40 55 3.8 18 8 A B 6900% 6200% 10 A A A A Example 41 48 18 8 A B
6800% 6500% 10 A A A A Example 42 41 16 A B 6500% 6000% 20 A B B A
Example 43 52 17 7 A B 6500% 6000% 20 A B A A Example 44 43 18 A B
6200% 5500% 30 A B B A Example 45 55 18 9 A B 6000% 5600% 30 A B A
A Example 46 43 16 A B 5900% 5300% 30 A B B A Example 47 58 20 6 A
B 6100% 4900% 30 A B A A Example 48 45 19 A B 6200% 4700% 30 A B B
A Example 49 56 17 7 A B 5800% 4400% 40 A B A A Example 50 41 16 A
B 5800% 4500% 40 A B B A
TABLE-US-00007 TABLE 7 Primary Throwing Difference Appearance
Content of Element Rust Observation Power (%) in Coating of Zr Si
Sn Cu Prevention of sludge 210 V 160 V Voltage (V) Coating SDT CCT
SST Example 51 91 5.7 19 A B 6200% 5500% 30 A A A A Example 52 75
5.1 21 A B 5700% 5000% 30 A A A A Example 53 81 5.3 18 A B 5600%
5100% 30 A A A A Example 54 88 5.7 14 A B 5900% 4700% 30 A A A A
Example 55 72 4.8 17 A B 6000% 5000% 30 A A A A Example 56 72 18 6
A B 5900% 5100% 20 A B B A Example 57 85 21 A B 5700% 4800% 30 A B
B A Example 58 91 20 7 A B 5900% 5100% 20 A B B A Example 59 94 18
A B 6000% 5200% 30 A B B A Example 60 44 3.2 15 A B 6200% 5500% 30
A A A A Example 61 46 3.1 19 A B 6100% 5100% 30 A A A A Example 62
49 3.6 18 A B 6000% 5300% 30 A A A A Example 63 38 3 20 A B 6500%
5700% 20 A A A A Example 64 44 3.2 16 A B 6600% 5500% 20 A A A A
Example 65 41 3.5 17 A B 6100% 5800% 20 A A A A Example 66 49 3.2
16 A B 6200% 5500% 30 A A A A Example 67 41 3.2 15 7 A B 6800%
5900% 20 A A A A Example 68 51 18 7 A B 5900% 5300% 30 A B A A
Example 69 52 18 5 A B 6300% 5100% 30 A B A A Example 70 48 19 9 A
B 6100% 5300% 30 A B A A Example 71 55 17 6 A B 6500% 5500% 30 A B
A A Example 72 43 16 10 A B 6200% 5800% 20 A B A A Example 73 49 20
7 A B 6600% 5400% 20 A B A A Example 74 52 17 5 A B 6200% 5200% 30
A B A A Example 75 67 4.7 18 A B 5900% 5200% 30 A A A A Example 76
54 3.2 16 A B 6200% 5800% 20 A A A A Example 77 48 2.8 17 A B 5900%
5000% 30 A A A A Comparative 58 4.2 B B 2200% 1000% 80 C B D B
Example 6
TABLE-US-00008 TABLE 8 Content of Primary Throwing Difference
Appearance Element Rust Observation Power (%) in Coating of Zr Si
Sn Cu Prevention of sludge 210 V 160 V Voltage (V) Coating SDT CCT
SST Example 78 55 13 A B 5800% 5000% 40 B C B B Example 79 44 24 A
B 5800% 2500% 40 B C B B Example 80 49 21 A B 6900% 5500% 30 A C A
B Example 81 45 18 A B 5900% 5000% 20 A C A B Example 82 38 26 A B
6000% 5000% 20 A C A B Example 83 45 9 A B 5900% 5100% 20 A C A B
Example 84 51 18 A B 5800% 5200% 20 A C A B Example 85 43 21 A B
6000% 5400% 20 A C A B Example 86 36 18 A B 6100% 5300% 10 A C A B
Example 87 47 23 A B 5900% 5100% 10 A C A B Example 88 32 33 A B
6000% 5300% 20 A C A B Example 89 52 12 A B 6100% 5300% 20 A C A B
Example 90 42 21 A B 6000% 5100% 20 A C A B Example 91 36 28 A B
5900% 5300% 20 A C A B Example 92 50 22 A B 6000% 5100% 30 A C B B
Example 93 50 24 A A 5500% 4800% 30 B C B B Example 94 46 26 A B
5800% 4900% 30 B C B B Example 95 46 15 A A 6000% 5100% 20 A C A B
Example 96 30 21 A B 5600% 4800% 40 B C B B Example 97 65 26 A B
5700% 4700% 30 A C B B Example 98 42 19 A B 5300% 5000% 30 A C B B
Example 99 72 21 A B 5200% 4900% 30 A C B B Example 100 33 10 A B
5600% 3200% 40 B C B B Example 101 43 22 A B 5200% 5200% 20 A C B B
Example 102 40 24 A B 5800% 4200% 20 A C B B Example 103 43 16 A B
5700% 4800% 30 B C B B Example 104 41 17 A B 5400% 3400% 30 A C B B
Example 105 40 21 A B 5700% 3300% 30 A C B B Example 106 40 11 A B
5500% 4500% 30 A C B B
INDUSTRIAL APPLICABILITY
[0128] The metal surface treatment liquid for cation
electrodeposition coating of the present invention is applicable to
metal base materials, such as automobile bodies and parts to be
subjected to cation electrodeposition.
* * * * *