U.S. patent application number 12/333435 was filed with the patent office on 2009-12-31 for method for surface treating plastic products.
This patent application is currently assigned to SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.. Invention is credited to CHENG-SHIN CHEN, ZHI-FENG LIN, YUN-CHEN MAO, JONG-YI SU, REN-NING WANG.
Application Number | 20090321267 12/333435 |
Document ID | / |
Family ID | 41446094 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090321267 |
Kind Code |
A1 |
SU; JONG-YI ; et
al. |
December 31, 2009 |
METHOD FOR SURFACE TREATING PLASTIC PRODUCTS
Abstract
A method for surface treating plastic products is provided. The
method includes the steps of providing a plastic substrate, the
plastic substrate being made of electroplatable material; forming
at least one electroconductive coating on the plastic substrate
surface by electro-less plating; forming a copper layer on the
electroconductive coating by electroplating; partially etching the
surface of the copper layer using a laser to form a rough area; and
forming a top coating on the copper layer by electroplating. Both
shiny appearance and dusky appearance of the plastic substrate can
be present by this method.
Inventors: |
SU; JONG-YI; (Shindian,
TW) ; CHEN; CHENG-SHIN; (Shindian, TW) ; WANG;
REN-NING; (Shenzhen City, CN) ; MAO; YUN-CHEN;
(Shenzhen City, CN) ; LIN; ZHI-FENG; (Shenzhen
City, CN) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. Steven Reiss
288 SOUTH MAYO AVENUE
CITY OF INDUSTRY
CA
91789
US
|
Assignee: |
SHENZHEN FUTAIHONG PRECISION
INDUSTRY CO., LTD.
ShenZhen City
CN
FIH (Hong Kong) LIMITED
Kowloon
HK
|
Family ID: |
41446094 |
Appl. No.: |
12/333435 |
Filed: |
December 12, 2008 |
Current U.S.
Class: |
205/159 |
Current CPC
Class: |
C25D 9/08 20130101; C23C
18/30 20130101; C23C 18/2086 20130101; C25D 5/12 20130101; C25D
5/48 20130101; C25D 5/10 20130101; C23C 18/1653 20130101; C23C
18/24 20130101 |
Class at
Publication: |
205/159 |
International
Class: |
C25D 5/56 20060101
C25D005/56 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2008 |
CN |
200810302387.0 |
Claims
1. A method for surface treating plastic products comprising:
providing a plastic substrate, the plastic substrate being made of
electroplatable material; forming at least one electroconductive
coating on a surface of the plastic substrate by electro-less
plating; forming a copper layer on the electroconductive coating by
electroplating; partially etching the copper layer using a laser to
form a rough area; and forming a top coating on the copper layer by
electroplating.
2. The method for surface treating plastic products as claimed in
claim 1, further comprising dipping the plastic substrate with the
copper layer in a protecting solution before etching the copper
layer.
3. The method for surface treating plastic products as claimed in
claim 2, wherein the protecting solution contains about 20 to 120
g/l potassium dichromate.
4. The method for surface treating plastic products as claimed in
claim 2, wherein the plastic substrate with the copper layer is
immersed in the protecting solution for about 1 to 5 minutes.
5. The method for surface treating plastic products as claimed in
claim 2, further comprising employing an electrolysis process to
treat the copper layer using the plastic substrate as a cathode,
the protecting solution as the electrolyte while the plastic
substrate with the copper layer is immerged in the protecting
solution.
6. The method for surface treating plastic products as claimed in
claim 5, wherein the electrolysis process is carried out at a
current density in an approximate range from 0.5 to 2 A/dm2.
7. The method for surface treating plastic products as claimed in
claim 2, further comprising a step of degreasing the plastic
substrate after etching the copper layer.
8. The method for surface treating plastic products as claimed in
claim 1, wherein the at least one electroconductive coating
includes a copper coating.
9. The method for surface treating plastic products as claimed in
claim 8, wherein the at least one electroconductive coating further
includes a nickel coating formed on the copper coating.
10. The method for surface treating plastic products as claimed in
claim 1, wherein the top coating is selected from a group
consisting of chrome, copper-zinc alloy, nickel, zinc, and tin.
11. The method for surface treating plastic products as claimed in
claim 1, further comprising degreasing, etching, and activating the
plastic substrate surface before the electro-less plating.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to methods for surface
treating plastic products, particularly to a method for surface
treating plastic products by which the plastic products can present
both shiny appearance and dull appearance.
[0003] 2. Description of Related Art
[0004] Various surface decorating technologies are used in
manufacturing housings of electronic devices. For example, in order
to obtain decorative effect, electroplating or painting is
typically employed to treat plastic housings of electronic devices,
e.g., mobile telephones, personal digital assistants, or MP3
players. The plastic housings treated by electroplating may be
favored by consumers because of their attractive metal appearance
and good abrasive resistance.
[0005] However, surfaces of the plastic housings treated by
electroplating usually only present one of the shiny appearance or
dull appearance. Thus, electroplated plastic housings are static in
appearance and so are not as attractive as they could be.
[0006] Therefore, there is room for improvement within the art.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0007] In a present embodiment, a method for surface treating
plastic products may include following steps.
[0008] In a first step, a plastic substrate is provided. The
substrate may be made of electroplatable material, such as
acrylonitrile-butadiene-styrene (ABS) resin.
[0009] In a second step, a pretreatment may be applied to the
plastic substrate. During the pretreatment step, the substrate is
degreased using an alkali-based cleaning solution to remove any oil
stains from its surface. After degreasing, the substrate is etched
to roughen the surface. The etching treatment can improve adhesion
of the surface of the substrate. During etching treatment, for
example, the degreased substrate can be immersed in a heated mixed
solution of chromic acid and sulfuric acid. Then, the etched
substrate is activated in an acidic colloid solution containing a
noble metal compound (e.g., palladium compound).
[0010] In a third step, at least one electroconductive coating is
formed on the surface of the pretreated substrate by a method of
electro-less plating. For example, a copper coating may be
deposited on the substrate. It is understood that a nickel coating
may be further formed on the copper coating.
[0011] In a fourth step, a copper layer is formed on the
electroconductive coating by electroplating. The electroplating
procedure is carried out, for example, in an bath containing copper
sulfate or cupric pyrophosphate.
[0012] In a fifth step, the substrate having the copper layer is
immersed in a protecting solution containing about 20 to 120 g/l
(gram per liter) potassium dichromate for about 1 to 5 minutes.
This process protects the electroplated copper layer from oxidation
and forming an oxide coating which may reduce adhesion of the
copper layer to a subsequent plating coating. It is better to
employ an electrolysis process to treat the substrate during the
fifth step. The electrolysis process is carried out in the
protecting solution using a graphite or carbon board as an anode,
the substrate as a cathode, and the protecting solution as an
electrolyte, at a current density in an approximate range from 0.5
to 2 A/dm2 (ampere per square decimeter).
[0013] In a sixth step, the copper layer is partially etched using
a laser to form a rough area. The rough area can be in any form of
figures, signs, and characters.
[0014] In a seventh step, the substrate is degreased using an
alkali-based cleaning solution to remove oil stains and/or other
smudginess.
[0015] In a eighth step, the substrate is cleaned using a solution
containing hydrochloric acid and sulfuric acid to neutralize the
residual alkali-based cleaning solution on the substrate.
[0016] In a ninth step, a top coating is formed on the copper layer
by electroplating. The material of the top coating may be selected
from chrome, copper-tin alloy, nickel, zinc and tin.
[0017] As mentioned above, because the copper layer forms a rough
area, the area of the top coating corresponding to the rough area
presents a dusky appearance, and the other portion of the top
coating presents a shiny appearance.
[0018] It should be understood, however, that even though numerous
characteristics and advantages of the present embodiments have been
set forth in the foregoing description, together with details of
the structures and functions of the embodiments, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the
principles of the invention to the full extent indicated by the
broad general meaning of the terms in which the appended claims are
expressed.
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