U.S. patent application number 16/317141 was filed with the patent office on 2019-08-01 for metal electrodeposition cathode plate and production method therefor.
This patent application is currently assigned to SUMITOMO METAL MINING CO., LTD.. The applicant listed for this patent is SUMITOMO METAL MINING CO., LTD.. Invention is credited to Hiroshi Kobayashi, Itsumi Matsuoka, Yusuke Senba, Hiroto Watanabe.
Application Number | 20190233960 16/317141 |
Document ID | / |
Family ID | 60992989 |
Filed Date | 2019-08-01 |
![](/patent/app/20190233960/US20190233960A1-20190801-D00000.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00001.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00002.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00003.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00004.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00005.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00006.png)
![](/patent/app/20190233960/US20190233960A1-20190801-D00007.png)
United States Patent
Application |
20190233960 |
Kind Code |
A1 |
Watanabe; Hiroto ; et
al. |
August 1, 2019 |
METAL ELECTRODEPOSITION CATHODE PLATE AND PRODUCTION METHOD
THEREFOR
Abstract
Provided are a metal electrodeposition cathode plate, the
non-conductive film of which is not susceptible to failure and
which can be used repeatedly, and a production method therefor.
This cathode plate comprises a metal plate on which multiple
disc-shaped protrusions are disposed, and a non-conductive film
formed on the non-protrusion flat areas of the metal plate. The
minimum film thickness Y of the non-conductive film at positions
between the centers of adjacent protrusions is the same or greater
than the height X of the protrusions. It is preferred that the
height X of the protrusions is 50 .mu.m to 1000 .mu.m.
Inventors: |
Watanabe; Hiroto;
(Niihama-shi, JP) ; Matsuoka; Itsumi;
(Niihama-shi, JP) ; Senba; Yusuke; (Niihama-shi,
JP) ; Kobayashi; Hiroshi; (Niihama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUMITOMO METAL MINING CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
SUMITOMO METAL MINING CO.,
LTD.
Tokyo
JP
|
Family ID: |
60992989 |
Appl. No.: |
16/317141 |
Filed: |
July 10, 2017 |
PCT Filed: |
July 10, 2017 |
PCT NO: |
PCT/JP2017/025093 |
371 Date: |
January 11, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C25C 7/02 20130101; C25D
17/12 20130101; C25C 1/08 20130101; C25C 7/08 20130101 |
International
Class: |
C25C 1/08 20060101
C25C001/08; C25C 7/02 20060101 C25C007/02; C25C 7/08 20060101
C25C007/08; C25D 17/12 20060101 C25D017/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 21, 2016 |
JP |
2016-143531 |
Claims
1. A metal electrodeposition cathode plate comprising: a metal
plate having a plurality of disc-shaped protrusions disposed on at
least one surface of the metal plate; and a non-conductive film
formed on a surface of the metal plate except the protrusions,
wherein a minimum film thickness of the non-conductive film at a
position between centers of the adjacent protrusions is the same as
or greater than a height of the protrusion.
2. The metal electrodeposition cathode plate according to claim 1,
wherein the height of the protrusion is 50 .mu.m or more and 1000
.mu.m or less.
3. The metal electrodeposition cathode plate according to claim 1,
wherein a difference between the minimum film thickness of the
non-conductive film at the position between centers of the adjacent
protrusions and the height of the protrusion is 200 .mu.m or
less.
4. The metal electrodeposition cathode plate according to claim 1,
wherein the metal plate is formed of titanium or stainless
steel.
5. The metal electrodeposition cathode plate according to claim 1,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
6. A method for producing a metal electrodeposition cathode plate,
comprising: a first step of forming a plurality of disc-shaped
protrusions on at least one surface of a metal plate; and a second
step of forming a non-conductive film on a surface of the metal
plate except the protrusions, wherein a minimum film thickness of
the non-conductive film at a position between centers of the
adjacent protrusions is set to be the same as or greater than a
height of the protrusion in the second step.
7. The metal electrodeposition cathode plate according to claim 2,
wherein a difference between the minimum film thickness of the
non-conductive film at the position between centers of the adjacent
protrusions and the height of the protrusion is 200 .mu.m or
less.
8. The metal electrodeposition cathode plate according to claim 2,
wherein the metal plate is formed of titanium or stainless
steel.
9. The metal electrodeposition cathode plate according to claim 3,
wherein the metal plate is formed of titanium or stainless
steel.
10. The metal electrodeposition cathode plate according to claim 7,
wherein the metal plate is formed of titanium or stainless
steel.
11. The metal electrodeposition cathode plate according to claim 2,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
12. The metal electrodeposition cathode plate according to claim 3,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
13. The metal electrodeposition cathode plate according to claim 4,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
14. The metal electrodeposition cathode plate according to claim 7,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
15. The metal electrodeposition cathode plate according to claim 8,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
16. The metal electrodeposition cathode plate according to claim 9,
wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
17. The metal electrodeposition cathode plate according to claim
10, wherein the metal electrodeposition cathode plate is used in
production of electric nickel for plating.
Description
TECHNICAL FIELD
[0001] The present invention relates to a metal electrodeposition
cathode plate and a production method therefor.
BACKGROUND ART
[0002] Conventionally, electric nickel serving as an anode raw
material for nickel plating has been used by being placed in a
titanium basket to be an anode holding tool and hung in a nickel
plating tank. At this time, as the electric nickel of an anode raw
material, those obtained by cutting plate-shaped electric nickel
electrodeposited on a cathode plate into small pieces have been
used.
[0003] However, the corner of the small pieces of electric nickel
is sharp, and it has been thus difficult to handle the electric
nickel when charging the electric nickel into a titanium basket. In
addition, the small pieces of electric nickel cause so-called
scaffold bridging as the corner thereof is caught by the mesh of
the titanium basket after the electric nickel was charged in the
titanium basket, the filling state of electric nickel in the
titanium basket changes, and this causes plating unevenness in some
cases.
[0004] Hence, it has been proposed to use blobby (button-shaped)
electric nickel with rounded corner. The blobby electric nickel can
be produced, for example, by precipitating nickel on a conductive
portion by using a cathode plate on which a plurality of circular
conductive portions is disposed at regular intervals by
electrolysis and then peeling off the electrodeposited nickel from
the conductive portion. According to such a method, it is possible
to efficiently produce a plurality of pieces of blobby electric
nickel from one cathode plate.
[0005] FIG. 5 is a view illustrating an example of a conventional
cathode plate to be used in production of blobby electric nickel. A
cathode plate 11 is masked with a non-conductive film 13 on a flat
plate-shaped metal plate 12 except the place to be a conductive
portion 12a, and the conductive portion 12a is a concave portion
and the non-conductive film 13 is a convex portion on this cathode
plate 11. Nickel having a proper size is electrodeposited on the
conductive portion 12a and blobby electric nickel is thus produced
by using such a cathode plate 11.
[0006] As a method for forming the non-conductive film 13 on the
metal plate 12 as the cathode plate 11, for example, there is a
method for forming a non-conductive film 13 having a desired
pattern by coating a thermosetting non-conductive resin such as an
epoxy resin on the flat plate-shaped metal plate 12 by a screen
printing method and heating the thermosetting non-conductive resin
as illustrated in FIG. 6A (see Patent Documents 1 and 2).
Incidentally, FIG. 6B illustrates a state in which nickel (electric
nickel) 14 is electrodeposited and precipitated on the conductive
portion 12a by using the cathode plate 11 on which the
non-conductive film 13 is formed. In the cathode plate 11, the
nickel 14 begins to be electrodeposited and precipitated from the
conductive portion 12a, grows not only in the thickness
(longitudinal) direction but also in the planar (lateral)
direction, and is in the state of being piled on the upper portion
of the non-conductive film 13 as well.
[0007] In addition, for example, there has also been proposed a
method for forming a non-conductive film 23 having a desired
pattern by coating a photosensitive non-conductive resin on a metal
plate 22 and removing the non-conductive resin at the place
corresponding to a conductive portion 22a by exposure and
development as illustrated in FIG. 7A. Incidentally, FIG. 7B
illustrates a state in which nickel (electric nickel) 24 is
electrodeposited and precipitated on the conductive portion 22a by
using the cathode plate 21 on which the non-conductive film 23 is
formed. In the cathode plate 21 as well, the nickel 24 begins to be
electrodeposited and precipitated from the conductive portion 22a
and grows not only in the thickness direction but also in the
planar direction.
[0008] Furthermore, there has also been proposed a method for
producing a cathode plate constituting a non-conductive portion by
solidifying the periphery of a metal structure incorporated so that
a plurality of studs to be a conductive portion is disposed at
regular intervals with an insulating resin by an injection molding
method (see Patent Document 3).
Patent Document 1: Japanese Examined Patent Application Publication
No. S51-036693 Patent Document 2: Japanese Unexamined Patent
Application, Publication No. S52-152832 Patent Document 3: Japanese
Examined Patent Application Publication No. S56-029960
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0009] Meanwhile, in a case in which blobby electric nickel is
produced using a cathode plate as described above, it is required
that the non-conductive film (non-conductive portion) to be formed
on the cathode plate has a long service life and can be easily
maintained even in the case of being lost (deteriorated).
[0010] The film thickness of the non-conductive film 13 gradually
decreases toward the conductive portion 12a and is thus
significantly thin at the boundary with the conductive portion 12a
in a case in which the non-conductive film 13 is formed by coating
a non-conductive resin on the metal plate 12 by screen printing as
illustrated in FIG. 6A. Such a change in the film thickness of the
non-conductive film 13 depends on the amount of the non-conductive
resin coated, the viscosity and temperature characteristics of
viscosity of the non-conductive resin, the curing temperature of
the non-conductive resin, the surface roughness and surface free
energy of the metal surface, and the like. Hence, the film
thickness of the non-conductive film 13 is significantly thin at
the boundary with the conductive portion 12a.
[0011] As described above, the nickel 14 begins to be
electrodeposited and precipitated from the conductive portion 12a,
grows not only in the longitudinal direction but also in the
lateral direction, and thus is in the state of gradually being
piled on the non-conductive film 13 as well when blobby electric
nickel is produced by using the cathode plate 11 as illustrated in
FIG. 5 and FIG. 6. Hence, the part of the thin non-conductive film
13 to be formed in the vicinity of the boundary with the conductive
portion 12a is likely to be lost by the stress at the time of
electrodeposition of the nickel 14 and the impact at the time of
peeling off of the electric nickel as well as the adhesive property
of the part with the metal plate 12 is likely to diminish by
penetration of the electrolytic solution. In addition, the
non-conductive film 13 in the vicinity of the non-conductive film
13 lost rises from the surface of the metal plate 12 when loss of
the non-conductive film 13 once occurs, thus the electrolytic
solution is more likely to enter the gap, and as a result, the
electrolytic solution gets into the gap of the non-conductive film
13 risen from the surface of the metal plate 12 and the nickel 14
is electrodeposited when it is attempted to continuously
electrodeposit nickel. Thereafter, the non-conductive film 13 in
which the nickel 14 is bitten is further lost when it is attempted
to peel off the nickel 14 electrodeposited by being gotten into the
gap.
[0012] In this manner, in the conventional cathode plate 11, when
loss of the non-conductive film 13 occurs and the lost part expands
in a chain reaction, the nickel 14 grown from the adjacent
conductive portions 12a is likely to be connected to each other,
electric nickel having a desired shape cannot be obtained, and a
defective product is produced. Accordingly, it is required to peel
off the entire non-conductive films 13 before loss of the
non-conductive film 13 occurs, to form the non-conductive film 3
again, and thus to maintain the cathode plate 11. However, in
reality, it is required to perform maintenance of the cathode plate
11 at the stage at which the electrodeposition treatment of nickel
is conducted about from several times to at most less than 10
times, and not only the productivity decreases but the maintenance
cost also increases.
[0013] On the other hand, it is possible to form the non-conductive
film 23 having a uniform film thickness in the cathode plate 21 in
which the non-conductive film 23 is formed using a photosensitive
non-conductive resin by exposure and development as illustrated in
FIG. 7A. However, the nickel 24 is caught by the step of the
non-conductive film 23 constituting the convex portion when the
nickel 24 is peeled off after the electrodeposition, a large impact
is likely to be applied to the non-conductive film 23, and thus
loss of the non-conductive film 23 occurs in this case as well.
[0014] Incidentally, in the method for forming a non-conductive
portion by injection molding as in Patent Document 3, the
production cost of the cathode plate itself increases and it is
difficult to maintain the cathode plate in a case in which the
non-conductive portion is deteriorated although the service life of
the non-conductive portion to be formed increases.
[0015] In view of such conventional circumstances, an object of the
present invention is to provide a metal electrodeposition cathode
plate in which a non-conductive film on a metal plate is hardly
lost and which can be repeatedly used and a production method
therefor.
Means for Solving the Problems
[0016] The inventors of the present invention have carried out
intensive investigations in order to solve the problems described
above. As a result, it has been found out that the non-conductive
film is hardly lost as protrusions are provided on a metal plate to
form a conductive portion and a non-conductive film is provided on
the metal surface except the protrusions, whereby the present
invention has been completed.
[0017] (1) A first aspect of the present invention is a metal
electrodeposition cathode plate, which includes a metal plate
having a plurality of disc-shaped protrusions disposed on at least
one surface of the metal plate and a non-conductive film formed on
a surface of the metal plate except the protrusions, in which a
minimum film thickness of the non-conductive film at a position
between centers of the adjacent protrusions is the same as or
greater than a height of the protrusion.
[0018] (2) A second aspect of the present invention is the metal
electrodeposition cathode plate according to the first aspect, in
which the height of the protrusion is 50 .mu.m or more and 1000
.mu.m or less.
[0019] (3) A third aspect of the present invention is the metal
electrodeposition cathode plate according to the first or second
aspect, in which a difference between the minimum film thickness of
the non-conductive film at the position between centers of the
adjacent protrusions and the height of the protrusion is 200 .mu.m
or less.
[0020] (4) A fourth aspect of the present invention is the metal
electrodeposition cathode plate according to any one of the first
to third aspects, in which the metal plate is formed of titanium or
stainless steel.
[0021] (5) A fifth aspect of the present invention is the metal
electrodeposition cathode plate according to any one of the first
to fourth aspects, in which the metal electrodeposition cathode
plate is used in production of electric nickel for plating.
[0022] (6) A sixth aspect of the present invention is a method for
producing a metal electrodeposition cathode plate, which includes a
first step of forming a plurality of disc-shaped protrusions on at
least one surface of a metal plate and a second step of forming a
non-conductive film on a surface of the metal plate except the
protrusions, in which a minimum film thickness of the
non-conductive film at a position between centers of the adjacent
protrusions is set to be the same as or greater than a height of
the protrusion in the second step.
Effects of the Invention
[0023] According to the present invention, it is possible to
provide a metal electrodeposition cathode plate in which a
non-conductive film is hardly lost and which can be repeatedly used
and a production method therefor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a plan view illustrating a configuration of a
cathode plate.
[0025] FIG. 2 is an enlarged cross-sectional view of a main part
illustrating a configuration of a cathode plate, FIG. 2A is an
enlarged cross-sectional view of a main part for describing the
state of a cathode plate before nickel electrodeposition, and FIG.
2B is an enlarged cross-sectional view of a main part for
describing the state of a cathode plate after nickel
electrodeposition.
[0026] FIG. 3 is an enlarged cross-sectional view of a main part
illustrating a configuration of a cathode plate in a case in which
the film thickness of the non-conductive film is thin, FIG. 3A is
an enlarged cross-sectional view of a main part for describing the
state of a cathode plate before nickel electrodeposition, and FIG.
3B is an enlarged cross-sectional view of a main part for
describing the state of a cathode plate after nickel
electrodeposition.
[0027] FIG. 4 is an enlarged cross-sectional view of a main part
for describing a method for producing a cathode plate, FIG. 4A is
an enlarged cross-sectional view of a main part for describing a
first step, and FIG. 4B is an enlarged cross-sectional view of a
main part for describing a second step.
[0028] FIG. 5 is a plan view illustrating a configuration of a
conventional cathode plate.
[0029] FIG. 6 is an enlarged cross-sectional view of a main part
illustrating a configuration of a conventional cathode plate, FIG.
6A is an enlarged cross-sectional view of a main part for
describing the state of a cathode plate before nickel
electrodeposition, and FIG. 6B is an enlarged cross-sectional view
of a main part for describing the state of a cathode plate after
nickel electrodeposition.
[0030] FIG. 7 is an enlarged cross-sectional view of a main part
illustrating a configuration of a conventional cathode plate, FIG.
7A is an enlarged cross-sectional view of a main part for
describing the state of a cathode plate before nickel
electrodeposition, and FIG. 7B is an enlarged cross-sectional view
of a main part for describing the state of a cathode plate after
nickel electrodeposition.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
[0031] Hereinafter, an embodiment (hereinafter referred to as the
"present embodiment") in which the metal electrodeposition cathode
plate of the present invention is applied to a metal
electrodeposition cathode plate to be used in the production of
electric nickel will be described in detail. It should be noted
that the present invention is not limited to the following
embodiments and can be appropriately changed without changing the
gist of the present invention.
<1. Metal Electrodeposition Cathode Plate>
(1) Configuration of Cathode Plate
[0032] A cathode plate 1 according to the present embodiment
includes a metal plate 2 on which a plurality of disc-shaped
protrusions 2a is disposed and a non-conductive film 3 formed on
the surface of the metal plate 2 except the protrusions 2a as
illustrated in FIG. 1. The cathode plate 1 is used, for example, by
being hung in an electrolytic cell containing an electrolytic
solution containing nickel and an anode by a hanging member 5 and
nickel having a desired shape is electrodeposited and precipitated
on the surface of the cathode plate as to be described later.
[Metal Plate]
[0033] The metal plate 2 is a plate of a metal having a flat plate
shape and has a plurality of disc-shaped protrusions 2a as
illustrated in FIG. 1 and FIG. 2A. Here, the surface of the metal
plate 2 except the protrusion 2a is referred to as a "flat area 2b"
with respect to the protrusion 2a. In addition, the "height X of
the protrusion" is the protruding height from the surface of the
flat area 2b of the metal plate 2.
[0034] Incidentally, an example in which the protrusion 2a is
provided on one surface of the metal plate 2 is illustrated in FIG.
2, but the protrusion 2a may be provided on both surfaces of the
metal plate 2.
[0035] The size of the metal plate 2 is not particularly limited,
and it may be set according to the desired size and number of
electric nickel to be produced as appropriate. For example, the
size can be set to a rectangular size of which one side is 100 mm
or more and 2000 mm or less. In addition, the thickness of the
metal plate 2 is preferably, for example, about 1.5 mm or more and
about 5 mm or less in a case in which the protrusion 2a is provided
on one surface, and it is preferably, for example, about 3 mm or
more and about 10 mm or less in a case in which the protrusion 2a
is provided on both surfaces. There is a tendency that warpage is
likely to occur by the protrusion 2a and the flat area 2b when the
thickness of the metal plate 2 is too thin. On the other hand, the
weight of the metal plate 2 increases and it is difficult to handle
the metal plate 2 when the thickness of the metal plate 2 is too
thick.
[0036] The material for the metal plate 2 is not particularly
limited as long as it is a metal which is less susceptible to
corrosion by the electrolytic solution to be used and forms only
loose bonding with an electrodeposit such as nickel, but preferred
examples thereof may include titanium and stainless steel.
[0037] On the metal plate 2, a concave step is formed by the
adjacent protrusions 2a in order to form the non-conductive film 3
having a predetermined thickness as well as the surface of a
plurality of disc-shaped protrusions 2a is exposed from the
non-conductive film 3 to be described later and functions as a
conductive portion. Hereinafter, the surface of the protrusions 2a
to be exposed from the non-conductive film 3 is referred to as a
"conductive portion 2c" in some cases. Nickel 4 is electrodeposited
and precipitated on the conductive portion 2c by an electrolytic
treatment.
[0038] The size of the disc-shaped protrusion 2a may be set
according to the desired size of electric nickel as appropriate,
but the diameter thereof can be set to, for example, 5 mm or more
and 30 mm or less. In addition, the height X of the protrusion 2a
is preferably 50 .mu.m or more and 1000 .mu.m or less and more
preferably 100 .mu.m or more and 500 .mu.m or less. When the height
X of the protrusion 2a is too low, the film thickness of the
non-conductive film 3 to be formed on the flat area 2b of the metal
plate 2 is insufficient and the non-conductive film is likely to be
lost by the stress at the time of electrodeposition of the nickel 4
and the impact at the time of peeling off of the electric nickel.
On the other hand, when the height X of the protrusion 2a is too
high, for example, the number of coating increases and the
productivity decreases when forming a non-conductive film by screen
printing. In addition, when the height X is too high, distortion of
the metal plate 2 is likely to occur at the time of processing of
the protrusion 2a, the metal plate 2 is likely to warp, and it is
thus difficult to form the non-conductive film 3. Incidentally, it
is also possible to increase the thickness of the metal plate 2 in
order to diminish the influence of distortion of the metal plate 2,
but the weight of the metal plate 2 increases and it is difficult
to handle the metal plate.
[0039] In addition, fine concave and convex may be provided on the
surface of the metal plate 2, namely, on the surface of the
disc-shaped protrusion 2a of the metal plate 2 by sand blasting or
etching. This makes it possible to peel off the nickel 4
electrodeposited on the protrusion 2a with a proper impact without
falling off the nickel 4 during the electrolytic treatment. In this
case, it is preferable that the film thickness of the
non-conductive film 3 to be described later is two or more times
the maximum surface roughness Rz of the metal plate 2. There is
concern that pinholes and insulation failure portions are generated
on the non-conductive film 3 when the film thickness of the
non-conductive film 3 is thinner than two times the maximum surface
roughness Rz of the metal plate 2.
[Non-Conductive Film]
[0040] The non-conductive film 3 is formed on the flat area 2b,
which is the surface of the metal plate 2 except the protrusion 2a,
as illustrated in FIG. 2, and the surface of a plurality of
protrusions 2a disposed on the metal plate 2, namely, the
conductive portion 2c is put into a state of being exposed by this.
Moreover, the nickel 4 is formed by being individually divided into
a small blobby shape as the nickel 4 is electrodeposited and
precipitated on such a conductive portion 2c of the metal plate
2.
[0041] Here, in the cathode plate 1, the non-conductive film 3 is
formed on the flat area 2b having a concave step formed by the
adjacent protrusions 2a and thus the non-conductive film 3 having a
predetermined thickness is formed. In the cathode plate 1 according
to the present embodiment, the minimum film thickness Y of the
non-conductive film 3 is the same as or greater than the height X
of the protrusion 2a and it is preferably the same as the height
X.
[0042] Incidentally, the "minimum film thickness Y of the
non-conductive film" is defined as the minimum film thickness of
the non-conductive film 3 at a position between the centers of the
adjacent protrusions 2a. The non-conductive film 3 is formed as the
central portion between adjacent protrusions 2a is piled by the
surface tension as illustrated in FIG. 2A. In this case, the
minimum film thickness Y of the non-conductive film 3 is the film
thickness of the end portion in contact with the side face of the
protrusion 2a. In addition, the non-conductive film 3 may be formed
on the surface of the protrusion 2a in a case in which the film
thickness is thick. As the minimum film thickness Y of the
non-conductive film 3 at this time, not the film thickness of the
non-conductive film 3 formed on the surface of the protrusion 2a
but the minimum value among the film thicknesses of the
non-conductive films 3 formed at the position on the flat areas 2b
is taken. Incidentally, in the cathode plate 1, the film thickness
varies depending on the position of the protrusion 2a to be
selected but the minimum value among the film thicknesses is taken
as the minimum film thickness Y.
[0043] The non-conductive film 3 is formed on the flat area 2b
which is formed by the adjacent protrusions 2a and has a concave
step. Hence, the film thickness of the end portion of the
non-conductive film 3 is hardly thinned and the non-conductive film
3 is hardly lost even by the stress at the time of
electrodeposition of the nickel 4 and the impact at the time of
peeling off of the nickel 4 after electrodeposition as the
conventional non-conductive film 13 illustrated in FIG. 6. In
addition, the non-conductive film 3 does not protrude in a convex
shape and the end portion thereof is protected by the concave step
as the conventional non-conductive film 23 illustrated in FIG. 7.
Consequently, the impact to be applied to the end portion of the
non-conductive film 3 by the nickel 4 is minor and the
non-conductive film 3 is hardly lost even when the nickel 4 is
peeled off from the cathode plate 1. In this manner, in the cathode
plate 1, the non-conductive film 3 is hardly lost and it is thus
possible to repeatedly use the non-conductive film 3 in
electrodeposition without replacing the non-conductive film 3, to
decrease the maintenance cost, and to achieve improvement in the
productivity.
[0044] Furthermore, the minimum film thickness Y of the
non-conductive film 3 is the same as or greater than the height X
of the protrusion 2a, and the nickel 4 can be thus peeled off
without being caught by the peripheral portion of the protrusion 2a
when the nickel 4 is peeled off from the cathode plate 1. On the
other hand, in a case in which the minimum film thickness Y of the
non-conductive film 3 is less than the height X of the protrusion
2a as illustrated in FIG. 3, it is difficult to peel off the
electrodeposited nickel 4 since the electrodeposited nickel 4 is
caught by the peripheral portion of the protrusion 2a, for example,
at the place denoted by "A" in the drawing when the
electrodeposited nickel 4 is peeled off from the cathode plate
1.
[0045] The upper limit of the minimum film thickness Y of the
non-conductive film 3 is not particularly limited, but the
difference (Y-X) between the minimum film thickness Y and the
height X of the protrusion 2a is preferably 200 .mu.m or less, more
preferably 100 .mu.m or less, still more preferably 50 .mu.m or
less, and particularly preferably 5 .mu.m or less. Here, as
described above, the minimum film thickness Y of the non-conductive
film 3 is not particularly limited as long as it is the same as or
greater than the height X of the protrusion 2a, but it is not
required to set the minimum film thickness Y thicker than
necessary. For example, it is difficult to coat the non-conductive
film 3 so as to have a film thickness thicker than the height X of
the protrusion 2a by more than 200 .mu.m by screen printing. It is
required to conduct coating while finely adjusting the size of the
pattern of the screen plate plural times when it is attempted to
form the non-conductive film 3 having a film thickness thicker than
the height X of the protrusion 2a by more than 200 .mu.m by screen
printing, and thus the adjustment is difficult and the productivity
decreases.
[0046] Incidentally, in a case in which the non-conductive film 3
is formed on the flat area 2b on the metal plate 2 by the screen
printing method, the material for the non-conductive film 3 is
coated on the surface of the protrusion 2a as well, thus the
surface area of the conductive portion 2c decreases and the initial
current density increases in some cases, but there is no problem as
long as troubles are not caused in the characteristics of the
electrodeposited nickel 4. In addition, the non-conductive film 3
attached on the surface of the protrusion 2a is likely to be lost
since the film thickness thereof is extremely thin, but the
non-conductive film 3 to be formed on the flat area 2b has no
problem since the film thickness thereof is thick and the loss
thereof is suppressed.
[0047] The non-conductive film 3 is not particularly limited as
long as it is formed from a material which is non-conductive and is
less susceptible to corrosion by the electrolytic solution to be
used. For example, it is preferable that the non-conductive film 3
is composed of a thermosetting resin or a photocuring (ultraviolet
curing and the like) resin from the viewpoint of being easy to form
the film. Specific examples thereof may include an insulating resin
such as an epoxy-based resin, a phenol-based resin, a
polyamide-based resin, or a polyimide-based resin.
(2) Production of Electric Nickel Using Cathode Plate
[0048] In the cathode plate 1 having the configuration described
above, the surface of the protrusion 2a to be exposed from the
non-conductive film 3 is the conductive portion 2c and the nickel 4
is electrodeposited and precipitated thereon as illustrated in FIG.
2B. In the cathode plate 1, the nickel 4 grows not only in the
thickness direction but also in the planar direction and is thus in
the state of being piled on the upper part of the non-conductive
film 3. For this reason, it is preferable to terminate the
electrodeposition before the nickel 4 grown from the conductive
portion 2c of the surface of the adjacent protrusion 2a comes into
contact with each other.
[0049] Thereafter, a plurality of pieces of blobby electric nickel
can be obtained from one cathode plate 1 by peeling off the nickel
4 from the cathode plate 1 after the electrodeposition of nickel is
terminated. As described above, in the cathode plate 1 according to
the present embodiment, the non-conductive film 3 is hardly lost
and it is thus possible to repeatedly use the non-conductive film 3
without replacing the non-conductive film 3, to decrease the
maintenance cost, and to achieve improvement in the
productivity.
[0050] Incidentally, in the cathode plate 1 according to the
present embodiment, the nickel 4 is electrodeposited but silver,
gold, zinc, tin, chromium, cobalt, or any alloy thereof may be
electrodeposited without being limited to nickel.
<2. Method for Producing Metal Electrodeposition Cathode
Plate>
[0051] The method for producing a cathode plate 1 according to the
present embodiment includes a first step (FIG. 4A) of forming a
plurality of disc-shaped protrusions 2a on at least one surface of
a metal plate 2 and a second step (FIG. 4B) of forming a
non-conductive film 3 on the surface of the metal plate 2 except
the protrusions 2a as illustrated in FIG. 4.
[First Step]
[0052] In the first step, a plurality of disc-shaped protrusions 2a
is formed on the surface of the metal plate 2. For example, the
parts of the flat plate-shaped metal plate 2 except the protrusions
2a are scraped, the protrusions 2a having a height X are left, and
flat areas 2b are thus formed. The processing method is not
particularly limited, and the formation of flat areas 2b can be
conducted by, for example, wet etching processing, end mill
processing, and laser processing.
[0053] For example, in the case of processing a flat plate-shaped
stainless steel plate by wet etching, a photosensitive etching
resist is coated on the surface of a stainless steel plate and is
then exposed by passing through a film or glass on which a desired
pattern is drawn and the etching resist of the part to be etched is
removed by a development treatment. Thereafter, the stainless steel
plate developed is dipped in an etching solution (for example, a
ferric chloride solution), a part of the stainless steel plate from
which the etching resist has been removed is removed, and finally,
the etching resist is peeled off, whereby a plurality of
disc-shaped protrusions 2a matching with a desired pattern can be
formed.
[0054] Incidentally, the protrusions 2a may be formed only on one
surface of the metal plate 2 or on both surfaces of the metal plate
2.
[Second Step]
[0055] In the second step, the non-conductive film 3 is formed on
the flat areas 2b to be the surface of the metal plate 2 except the
protrusions 2a. The method for forming the non-conductive film 3 is
not particularly limited, and the formation of the non-conductive
film 3 can be conducted by screen printing. In a case in which the
material for the non-conductive film 3 is a thermosetting resin or
a photocurable resin, heat curing or photocuring may be conducted
if necessary.
[0056] At this time, the non-conductive film 3 is formed so that
the minimum film thickness Y of the non-conductive film 3 at the
position between the centers of adjacent protrusions 2a is the same
as or greater than the height X of the protrusion 2a. In a case in
which a desired film thickness cannot be obtained by one time of
screen printing, the above-described screen printing and heat
curing or photocuring may be repeated until the desired film
thickness is obtained.
[0057] According to the method for producing a cathode plate
according to the present embodiment, it is possible to obtain the
cathode plate 1 in which the non-conductive film on the metal plate
is hardly lost and which can be repeatedly used.
EXAMPLES
[0058] Hereinafter, the present invention will be described more
specifically with reference to Examples, but the present invention
is not limited by these Examples at all. It should be noted that
members having the same functions as the members illustrated in
FIG. 1 to FIG. 6 are denoted by the same reference numerals for the
sake of convenience.
<Fabrication of Cathode Plate>
Example 1
[0059] A cathode plate 1 as illustrated in FIG. 1 and FIG. 2 was
fabricated. Specifically, first, a metal plate 2 which was made of
stainless steel and had a size of 200 mm.times.100 mm.times.4 mm
was subjected to wet etching to form disc-shaped protrusions 2a (18
pieces). At this time, the size of the protrusion 2a was set to a
diameter of 14 mm and a height X of 300 .mu.m, and the minimum
center-distance between adjacent protrusions 2a was set to 21
mm.
[0060] Next, a thermosetting epoxy resin was coated on flat areas
2b of the metal plate 2 by a screen printing method and cured by
heating at 150.degree. C. for 60 minutes to form a non-conductive
film 3. In the cathode plate 1 fabricated in this manner, the
difference between the minimum film thickness Y of the
non-conductive film 3 and the height X of the protrusion at a
position between the centers of adjacent protrusions 2a was
measured at arbitrary 10 places by using a laser displacement
meter, and the results were in a range of from 40 to 70 .mu.m and
the minimum film thickness Y of the non-conductive film 3 was thus
340 .mu.m.
Example 2
[0061] A cathode plate 1 was fabricated in the same manner as in
Example 1 except that the height X of the protrusion 2a of the
metal plate 2 was set to 500 .mu.m and the non-conductive film 3
was formed on the flat area 2b so as to have a predetermined
thickness. In the cathode plate 1 fabricated in this manner, the
difference between the minimum film thickness Y of the
non-conductive film 3 and the height X of the protrusion 2a was
measured at arbitrary 10 places by using a laser displacement
meter, and the results were in a range of from 10 to 50 .mu.m and
the minimum film thickness Y of the non-conductive film 3 was thus
510 .mu.m.
Example 3
[0062] A cathode plate 1 was fabricated in the same manner as in
Example 1 except that the height X of the protrusion 2a of the
metal plate 2 was set to 60 .mu.m and the non-conductive film 3 was
formed on the flat area 2b so as to have a predetermined thickness.
In the cathode plate 1 fabricated in this manner, the difference
between the minimum film thickness Y of the non-conductive film 3
and the height X of the protrusion was measured at arbitrary 10
places by using a laser displacement meter, and the results were in
a range of from 60 to 90 .mu.m and the minimum film thickness Y of
the non-conductive film 3 was thus 120 .mu.m.
Example 4
[0063] A cathode plate 1 was fabricated in the same manner as in
Example 1 except that the height X of the protrusion 2a of the
metal plate 2 was set to 100 .mu.m and the non-conductive film 3
was formed on the flat area 2b so as to have a predetermined
thickness. In the cathode plate 1 fabricated in this manner, the
difference between the minimum film thickness Y of the
non-conductive film 3 and the height X of the protrusion was
measured at arbitrary 10 places by using a laser displacement
meter, and the results were in a range of from 100 to 150 .mu.m and
the minimum film thickness Y of the non-conductive film 3 was thus
200 .mu.m.
Example 5
[0064] A cathode plate 1 was fabricated in the same manner as in
Example 1 except that the height X of the protrusion 2a of the
metal plate 2 was set to 40 .mu.m and the non-conductive film 3 was
formed on the flat area 2b so as to have a predetermined thickness.
In the cathode plate 1 fabricated in this manner, the difference
between the minimum film thickness Y of the non-conductive film 3
and the height X of the protrusion 2a was measured at arbitrary 10
places by using a laser displacement meter, and the results were in
a range of from 10 to 40 .mu.m and the minimum film thickness Y of
the non-conductive film 3 was thus 50 .mu.m.
Comparative Example 1
[0065] In Comparative Example 1, a conventional cathode plate 11 as
illustrated in FIG. 5 and FIG. 6 was fabricated.
[0066] Specifically, a thermosetting epoxy resin was coated on a
flat plate-shaped metal plate 12 which was made of stainless steel
and had a size of 200 mm.times.100 mm.times.4 mm except conductive
portions 12a (18 pieces) having a diameter of 14 mm by a screen
printing method and cured by heating at 150.degree. C. for 60
minutes to form a non-conductive film 13, whereby the cathode plate
11 was fabricated. In the cathode plate 11 fabricated in this
manner, the maximum film thickness of the non-conductive film 13
was measured at arbitrary 10 places by using a laser displacement
meter, and the results were in a range of from 90 to 110 .mu.m.
Comparative Example 2
[0067] A cathode plate was fabricated in the same manner as in
Example 1 except that the height X of the protrusion of the metal
plate was set to 500 .mu.m and the non-conductive film was formed
on the flat area so as to have a predetermined thickness. In the
cathode plate fabricated in this manner, the difference between the
minimum film thickness of the non-conductive film and the height of
the protrusion was measured at arbitrary 10 places by using a laser
displacement meter, and the results were in a range of from -200 to
-150 .mu.m and the minimum film thickness Y of the non-conductive
film 3 was thus 300 .mu.m. Incidentally, the minimum film thickness
Y of the non-conductive film 3 is thinner than 500 .mu.m of the
height of the protrusion.
Comparative Example 3
[0068] A metal plate which was made of stainless steel and had a
size of 200 mm.times.100 mm.times.4 mm was subjected to wet etching
to form protrusions (18 pieces) having a height of 2000 .mu.m.
However, warpage of the metal plate was severe and it was difficult
to form a non-conductive film by screen printing.
<Production of Electric Nickel>
[0069] Electric nickel was produced by an electrolytic treatment
using the cathode plates fabricated in the respective Examples and
Comparative Examples. Specifically, the cathode plate and an anode
plate which was composed of electric nickel and had a size of 200
mm.times.100 mm.times.10 mm were dipped in an electrolytic tank
containing a nickel chloride electrolytic solution so as to face
each other. Thereafter, nickel was electrodeposited on the surface
of the cathode plate under the conditions of an initial current
density of 710 A/m.sup.2 and an electrolysis time of 3 days. After
the electrolysis, the electric nickel precipitated on the cathode
plate was peeled off to obtain blobby electric nickel for
plating.
<Evaluation>
[0070] The number of times, by which the cathode plate used in the
electrolysis treatment was able to be repeatedly utilized as it
was, was evaluated. Nickel electrodeposited at the adjacent
protrusions and conductive portions are connected to each other and
electric nickel having a desired shape cannot be obtained in some
cases when the loss of the non-conductive film expands. Hence, the
use was stopped and the number of repetitions up to this time point
was evaluated in a case in which the non-conductive film was lost
from the boundary with the protrusion in the direction of the flat
area by 1 mm or more. In addition, the use was stopped and the
number of repetitions up to this time point was evaluated in a case
in which the non-conductive film was lost and the diameter of the
conductive portion increased by 1 mm or more as well.
[0071] The evaluation results are presented in the following Table
1 together with the configuration of the cathode plate.
TABLE-US-00001 TABLE 1 Height Minimum Maximum X of film film
protrusion thickness thickness Y - X Number of (.mu.m) Y (.mu.m)
(.mu.m) (.mu.m) repeated use Example 1 300 340 -- 40 20 or more
Example 2 500 510 -- 10 20 or more Example 3 60 120 -- 60 16
Example 4 100 200 -- 100 20 or more Example 5 40 50 -- 10 9
Comparative -- -- 90~110 -- 7 Example 1 Comparative 500 300 -- -200
(Difficult Example 2 to peel off)
[0072] As presented in Table 1, in Examples 1 to 5 using the
cathode plates 1 in which the non-conductive film 3 was formed on
the flat area 2b of the metal plate 2 and the minimum film
thickness Y of the non-conductive film 3 was the same as or greater
than the height X of the protrusion 2a, loss of the non-conductive
film 3 was suppressed and it was possible to sufficiently
repeatedly use the cathode plates 1. Particularly, in Examples 1 to
4 in which the height X of the protrusion 2a was 50 .mu.m or more,
the number of repeated use was more than 10 times.
[0073] On the other hand, in Comparative Example 1 in which the
non-conductive film 13 was formed in a convex shape on the flat
plate-shaped metal plate 12, the non-conductive film was lost and
it was not possible to sufficiently repeatedly use the cathode
plate. In addition, in Comparative Example 2 in which the minimum
film thickness Y of the non-conductive film was less than the
height X of the protrusion, nickel was caught by the peripheral
portion of the protrusion at the time of peeling off of nickel and
it was difficult to peel off nickel.
EXPLANATION OF REFERENCE NUMERALS
[0074] 1 CATHODE PLATE [0075] 2 METAL PLATE [0076] 2a PROTRUSION
[0077] 2b FLAT AREA [0078] 2c CONDUCTIVE PORTION [0079] 3
NON-CONDUCTIVE FILM [0080] 4 NICKEL
* * * * *