U.S. patent application number 11/322220 was filed with the patent office on 2006-07-27 for method of manufacturing abs resin molded part and abs resin molded part.
This patent application is currently assigned to NIKON CORPORATION. Invention is credited to Koji Hirade, Hidenori Miyamoto.
Application Number | 20060163777 11/322220 |
Document ID | / |
Family ID | 36695958 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060163777 |
Kind Code |
A1 |
Hirade; Koji ; et
al. |
July 27, 2006 |
Method of manufacturing ABS resin molded part and ABS resin molded
part
Abstract
An ABS resin molded part is manufactured by forming a molded
part of an ABS resin into which a particulate filler is mixed,
eluting butadiene particles from the surface of the molded part by
etching, and forming a plating coat on the surface after the
etching.
Inventors: |
Hirade; Koji; (Yokohama-shi,
JP) ; Miyamoto; Hidenori; (Urayasu-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
NIKON CORPORATION
TOKYO
JP
|
Family ID: |
36695958 |
Appl. No.: |
11/322220 |
Filed: |
January 3, 2006 |
Current U.S.
Class: |
264/331.13 ;
205/80; 216/83; 264/105; 264/328.18; 428/457 |
Current CPC
Class: |
B29C 45/0053 20130101;
Y10T 428/31855 20150401; B29B 7/90 20130101; B29C 2045/0079
20130101; B29C 45/0055 20130101; Y10T 428/254 20150115; C08K 3/04
20130101; B29C 59/00 20130101; Y10T 428/26 20150115; Y10T 428/25
20150115; B29C 45/0013 20130101; B29K 2055/02 20130101; Y10T
428/31678 20150401; Y10T 428/265 20150115; B29C 2045/0058 20130101;
Y10T 428/24521 20150115 |
Class at
Publication: |
264/331.13 ;
264/328.18; 264/105; 216/083; 205/080; 428/457 |
International
Class: |
C08J 5/00 20060101
C08J005/00; C25D 5/00 20060101 C25D005/00; B44C 1/22 20060101
B44C001/22; C04B 35/00 20060101 C04B035/00; B29B 7/00 20060101
B29B007/00; B32B 15/04 20060101 B32B015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 25, 2005 |
JP |
2005-017324 |
Claims
1. A method of manufacturing an ABS resin molded part, comprising
the steps of: forming a molded part of an ABS resin into which a
particulate filler is mixed; eluting butadiene particles from a
surface of the molded part by etching; and forming a plating coat
on the surface after the etching.
2. The method according to claim 1, wherein said molded part is
formed by injection molding the ABS resin into a mold and includes
a thick walled part and a thin walled part adjoining with each
other.
3. The method according to claim 1, wherein a thickness of said
plating coat is 10 .mu.m or less.
4. The method according to claim 1, wherein said filler is carbon
black.
5. The method according to claim 1, wherein an average particle
diameter of said filler is 0.5 .mu.m or less.
6. The method according to claim 1, wherein said ABS resin contains
said filler at 0.1 wt % or more to 0.5 wt % or less.
7. The method according to claim 2, wherein a thickness of said
plating coat is 10 .mu.m or less.
8. The method according to claim 7, wherein said filler is carbon
black.
9. The method according to claim 7, wherein an average particle
diameter of said filler is 0.5 .mu.m or less.
10. The method according to claim 7, wherein said ABS resin
contains said filler at 0.1 wt % or more to 0.5 wt % or less.
11. The method according to claim 8, wherein an average particle
diameter of said filler is 0.5 .mu.m or less.
12. The method according to claim 11, wherein said ABS resin
contains said filler at 0.1 wt % or more to 0.5 wt % or less.
13. The method according to claim 8, wherein said ABS resin
contains said filler at 0.1 wt % or more to 0.5 wt % or less.
14. An ABS resin molded part, wherein: an ABS resin into which a
particulate filler is mixed is injection molded; butadiene
particles is eluted from a surface of the injection molded ABS
resin by etching; and a plating coat is formed on the surface after
the etching.
15. The ABS resin molded part according to claim 14, wherein: said
ABS resin molded part includes a thick walled part and a thin
walled part adjoining with each other; and a thickness of said
plating coat is 10 .mu.m or less.
16. The ABS resin molded part according to claim 14, wherein said
filler is carbon black with an average particle diameter of 0.5
.mu.m or less.
17. An ABS resin molded part, comprising: an injection molded part
made of an ABS resin into which a particulate filler is mixed;
etching pits formed on a surface of said injection molded part by
etching butadiene particles; and a plating coat formed on the
surface of said injection molded part.
18. The ABS resin molded part according to claim 17, wherein said
injection molded part includes a thick walled part and a thin
walled part adjoining with each other.
19. The ABS resin molded part according to claim 17, wherein a
thickness of said plating coat is 10 .mu.m or less.
20. The ABS resin molded part according to claim 17, wherein said
filler is carbon black.
21. The ABS resin molded part according to claim 17, wherein an
average particle diameter of said filler is 0.5 .mu.m or less.
22. The ABS resin molded part according to claim 17, wherein said
ABS resin contains said filler at 0.1 wt % or more to 0.5 wt % or
less.
23. The ABS resin molded part according to claim 18, wherein a
thickness of said plating coat is 10 .mu.m or less.
24. The ABS resin molded part according to claim 23, wherein said
filler is carbon black with an average particle diameter of 0.5
.mu.m or less.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2005-017324, filed on
Jan. 25, 2005, the entire contents of which are incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of manufacturing a
plated ABS resin molded part and to an ABS resin molded part.
[0004] 2. Description of the Related Art
[0005] Heretofore, an injection molded part of an ABS resin has
been widely used in electronic and electric equipment, and various
kinds of plated part manufacturing methods have been proposed (See
Japanese Unexamined Patent Application Publication No. Hei 5-59587
and Japanese Unexamined Patent Application Publication No. Hei
5-230276). In particular, with greater demands for miniaturization,
cost reduction, and so on to the electronic equipment in recent
years, there have been great demands for a reduction in the
thickness of plating because an increase in the time taken for the
plating process, which is in proportion to the thickness of
plating, causes higher cost.
[0006] However, when thin film is plated on an injection molded
part of an ABS resin having a thick walled part and a thin walled
part adjoining with each other, there is a problem of uneven
plating, especially in the thin walled part. Accordingly, in order
to improve the yield of the part in such a case, the thickness of
plating has to be large to a certain extent in actual
conditions.
[0007] Note that Japanese Unexamined Patent Application Publication
No. Hei 5-59587 and Japanese Unexamined Patent Application
Publication No. Hei 5-230276 disclose techniques of improving
plating adhesiveness and so on, however, they do not describe
reducing uneven plating on the material surface of the ABS resin
molded part having the thick walled part and the thin walled part
adjoining with each other.
SUMMARY OF THE INVENTION
[0008] The present invention has been made in view of solving the
above-described problems of the related art. The object thereof is
to provide a means for greatly reducing uneven plating when
applying thin film plating to an injection molded part of an ABS
resin.
[0009] According to a first aspect of the present invention, a
method of manufacturing an ABS resin molded part includes the steps
of: forming a molded part of an ABS resin into which a particulate
filler is mixed; eluting butadiene particles from a surface of the
molded part by etching; and forming a plating coat on the surface
after the etching.
[0010] In the above-described first aspect, it is preferable that
the molded part be formed by injection molding the ABS resin into a
mold and include a thick walled part and a thin walled part
adjoining with each other. Preferably, a thickness of the plating
coat be 10 .mu.m or less, and the filler be carbon black.
Preferably, an average particle diameter of the filler be 0.5 .mu.m
or less. Preferably, the ABS resin contains the filler at 0.1 wt %
or more to 0.5 wt % or less.
[0011] According to a second aspect of the present invention, an
ABS resin molded part is such that an ABS resin into which a
particulate filler is mixed is injection molded, and butadiene
particles is eluted from a surface of the injection molded ABS
resin by etching, and a plating coat is formed on the surface after
the etching.
[0012] Further, according to a third aspect of the present
invention, an ABS resin molded part includes: an injection molded
part made of an ABS resin into which a particulate filler is mixed;
etching pits formed on a surface of the injection molded part by
etching butadiene particles; and a plating coat formed on the
surface of the injection molded part.
[0013] Here, it is preferable that the injection molded part in the
above-described second aspect or third aspect include a thick
walled part and a thin walled part adjoining with each other. In
the above-described second aspect and third aspect, preferably, a
thickness of the plating coat be 10 .mu.m or less. Preferably, the
filler be carbon black. Preferably, an average particle diameter of
the filler be 0.5 .mu.m or less. Preferably, the ABS resin contain
the filler at 0.1 wt % or more to 0.5 wt % or less.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The nature, principle, and utility of the invention will
become more apparent from the following detailed description when
read in conjunction with the accompanying drawings in which like
parts are designated by identical reference numbers, in which:
[0015] FIG. 1A to FIG. 1C shows butadiene particles and shapes of
etching pits in an ABS injection molded part of the present
embodiment; and
[0016] FIG. 2A to FIG. 2C shows butadiene particles and shapes of
etching pits in a conventional ABS injection molded part.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] A manufacturing method of an ABS resin molded part having a
plating coat according to an embodiment of the present invention
will be described below.
[0018] Firstly, carbon black is mixed as a particulate filler into
an ABS resin and dispersed. Then, the ABS resin into which the
carbon black is mixed is injected into a mold by an injection
molding machine to form an ABS resin molded part including a step
portion where a thick walled part and a thin walled part adjoin
with each other.
[0019] Secondly, the ABS resin molded part made in the
above-described first process is degreased, and thereafter etched.
By the etching, butadiene particles are decomposed by oxidation and
eluted from the surface of the ABS resin molded part. Thereby,
innumerable minute holes (etching pits) are formed on the surface
of the material. It is known that the adhesiveness between the
material surface and the plating coat is improved through the
above-described etching processing since plating metal is embedded
into the etching pits in the plating process (anchor effect). In
this embodiment, as described later, nearly circular and almost
isotropic etching pits are formed substantially evenly on the
surface of the ABS resin molded part. The etching pits are less
oriented in a direction in which the resin flows. Accordingly, the
density of etching pits does not differ much in-between the thin
walled part and the thick walled part of the molded part.
[0020] Thirdly, the etched ABS resin molded part is catalytically
treated through a catalyser-accelerator process or the like.
Thereafter, the catalytically treated surface is chemically plated
and then electroplated. Thus, the plating coat is formed on the ABS
resin molded part.
[0021] In this embodiment, the carbon black is mixed into the ABS
resin in order to reduce uneven plating which occurs in the thin
walled part of the ABS above-described resin molded part when
plated. The inventors of the present invention presumes the cause
of the uneven plating in the thin walled part based on
later-described experimental results and acquires the following
findings.
[0022] The ABS resin at the time of injection molding flows in the
mold with an AS phase 11 of acrylic and styrene turned into a
liquid state but butadiene remaining in a particulate state. The
butadiene particles 12 in the ABS resin have the property of
expanding and contracting by external force. Therefore, the shapes
of the butadiene particles 12 in an ABS resin molded part 10 change
according to molding conditions, the shape of the mold, and so on.
More specifically, when the molded part 10 includes the step
portion where the thick walled part and the thin walled part adjoin
with each other, the shapes of the butadiene particles 12 in the
thick walled part and the thin walled part differ as follows.
[0023] The narrower the width of the mold (thin walled part of the
molded part) is, the faster the ABS resin flows and the larger the
resistance acting on the butadiene particles 12 is. Namely, in the
narrow portion of the mold, the ABS resin flows at high speed, and
the butadiene particles 12 are extended by the resistance in a
direction where the resin flows. Accordingly, in the thin walled
part of the molded part 10, the butadiene particles 12 tend to be
transformed into a flat shape. On the other hand, the ABS resin
flows at relatively low speed in a wide portion of the mold, so
that, roughly spherical shape of the butadiene particles 12 is
maintained in the thick walled part of the molded part 10 without
being transformed so much (See FIG. 2A).
[0024] Accordingly, flat, shallow, and large etching pits 14 are
formed on the surface of the thin walled part in the etched step
portion while nearly circular, almost isotropic, and small etching
pits 14 are formed on the surface of the thick walled part (See
FIG. 2B and FIG. 2C). This causes a difference in the density of
etching pits between the thin walled part and the thick walled part
of the molded part. Therefore, it is conceivable that uneven
plating is very apt to occur in thin film plating of a film
thickness of 10 .mu.m or less because it is particularly
susceptible to the influence on the material surface. Note that in
the case of the thin film plating of the film thickness of 10 .mu.m
or less, it is desirable that the thickness of a plating coat be
usually 6 .mu.m or more, but a thickness less than 6 .mu.m is also
possible.
[0025] FIG. 1A to FIG. 1C shows a state where carbon black 13 is
mixed into the ABS resin. In FIG. 1A to FIG. 1C, the carbon black
13 enters between the butadiene particles 12 of the ABS resin. At
the injection molding, the butadiene particles 12 flow, holding the
carbon black 13, so that the butadiene particles 12 are not greatly
transformed even in the narrow portion of the mold (See FIG. 1A).
Hence, in this case, the shapes of the butadiene particles 12 which
solidify at the material surfaces of the thin walled part and the
thick walled part become almost uniform, reducing the difference in
the density of the etched etching pits 14 consequently (See FIG. 1B
and FIG. 1C). As described above, it is conceivable that in this
embodiment, unevenness in thin film plating is not apt to
occur.
[0026] If the average particle diameter of the carbon black exceeds
0.5 .mu.m, the adhesiveness between the material surface and the
plating coat and the appearance of the plating coat deteriorate.
Therefore, it is desirable that the average particle diameter of
the carbon black mixed into the ABS resin be 0.5 .mu.m or less.
Moreover, it is desirable that the average particle diameter of the
carbon black be 0.2 .mu.m or more, but a particle diameter less
than 0.2 .mu.m is also possible.
[0027] Further, it is desirable that the ABS resin contain the
carbon black at 0.1 wt % or more to 0.5 wt %, or less because of
the following reasons. If the carbon black content is less than 0.1
wt %, the butadiene particles are transformed in the thin walled
part due to a little carbon black, and uneven plating is
conspicuous in thin plating coat. On the other hand, if the carbon
black content exceeds 0.5 wt %, it results in overetching,
worsening the state of the surface after plating.
EXAMPLES
[0028] Examples of the present invention will be described below.
Through the experiment, five kinds of specimens with the same shape
are formed by the injection molding machine, using four kinds of
ABS resins different in the average particle diameter of the carbon
black and carbon black content, and an ABS resin containing no
carbon black. Here, UMG CYCOLAC 3001M is used as the ABS resin. The
shape of each of the specimens is set to include the step portion
where the thick walled part and the thin walled part adjoin with
each other.
[0029] Then, each of the specimens is subjected to degreasing,
etching, catalytic treatment, chemical plating, and electroplating
in order, and a plating coat with a thickness of 10 .mu.m is formed
on the surface thereof. Thereafter, the state of the surface of the
plating coat on each specimen is evaluated visually. Results
thereof will be shown in Table 1. TABLE-US-00001 TABLE 1 AVERAGE
PATRTICLE CARBON STATE OF DIAMETER OF BLACK SURFACE CARBON BLACK
CONTENT PLATING (.mu.m) (wt %) COAT COMPARATIVE -- -- X EXAMPLE
EXPERIMIMENT 1 0.2 0.1.about.0.2 .largecircle. EXPERIMIMENT 2 0.5
0.1.about.0.2 .largecircle. EXPERIMIMENT 3 0.2 0.3.about.0.5
.circleincircle. EXPERIMIMENT 4 0.5 0.3.about.0.5 .circleincircle.
.circleincircle.: EVEN .largecircle.: VERY SLIGHTLY UNEVEN X:
DISTINCTLY UNEVEN
[0030] In Experiment 1 (average particle diameter: 0.2 .mu.m,
content: 0.1 wt % to 0.2 wt %) and Experiment 2 (average particle
diameter: 0.5 .mu.m, content: 0.1 wt % to 0.2 wt %), a
substantially good plated surface is obtained on each of the
specimens although very slightly uneven plating is found in the
thin walled parts thereof. Further, in Experiment 3 (average
particle diameter: 0.2 .mu.m, content: 0.3 wt % to 0.5 wt %) and
Experiment 4 (average particle diameter: 0.5 .mu.m, content: 0.3 wt
% to 0.5 wt %), a very good plated surface is obtained on the
specimens without unevenness in plating between the thin walled
part and the thick walled part. However, remarkable uneven plating
is found on the surface of the specimen without carbon black
(comparative example).
[0031] (Supplementary Description of Embodiment)
[0032] The above-described embodiment describes the example in
which the carbon black is mixed as the particulate filler into the
ABS resin. However, any other particulate filler can be used as
long as it can maintain its solid state at a temperature when the
ABS resin is injection molded and suppress transformation of the
butadiene particles at the time of the injection molding.
[0033] For example, particles of an organic filler of glass beads,
silica, quartz powder, glass powder, silicate (calcium silicate,
kaoline, talc, clay, diatomaceous earth, or the like), metal oxide
(iron oxide, titanium oxide, zinc oxide, alumina, or the like),
metal carbonate (calcium carbonate, magnesium carbonate, or the
like), sulfate (calcium sulfate, barium sulfate, or the like),
ceramics (silicon carbide, boron nitride, or the like) may be mixed
into the ABS resin.
[0034] Further, the above-described embodiment describes the
example in which the thin film plating is formed on the ABS resin
molded part including the step portion where the thick walled part
and the thin walled part adjoin with each other. However, the
present invention is also applicable to a case where the thin film
plating is formed on an ABS resin molded part including a portion
whose thickness increases or decreases continuously.
[0035] The invention is not limited to the above embodiments and
various modifications may be made without departing from the spirit
and scope of the invention. Any improvement may be made in part or
all of the components.
* * * * *