Title: Process for forming metal layer on surface of resin molded product
Abstract: A resin molded product and a fine metal powder producing material are placed into a treating vessel. The fine metal powder producing material is brought into flowing contact with the surface of the resin molded product, thereby producing a fine metal powder, and forming a metal layer of the fine metal powder on the surface of the resin molded product. In this process, the metal layer of the fine metal powder can be formed firmly and at high density on the surface of the resin molded product. The metal layer exhibits a function as an electrically conductive layer. Therefore, a metal film having an excellent thickness accuracy, an excellent surface smoothness and a high peel strength can be formed in a simple manner on the metal layer by carrying out an electroplating treatment. In addition, it is possible for the metal layer itself to exhibit functions or properties such as an ornamentality.
Patent Number: 6,863,986 Issued on 03/08/2005 to Yoshimura, et al.
| Inventors:
|
Yoshimura; Kohshi (Hyogo, JP);
Nishiuchi; Takeshi (Osaka, JP);
Kikui; Fumiaki (Osaka, JP);
Tsujimoto; Shuji (Osaka, JP)
|
| Assignee:
|
Neomax Co., Ltd. (Osaka, JP)
|
| Appl. No.:
|
044986 |
| Filed:
|
January 15, 2002 |
Foreign Application Priority Data
| Apr 28, 1999[JP] | 11-121170 |
| Current U.S. Class: |
428/458; 428/208; 428/148 |
| Intern'l Class: |
B32B 009//00 |
| Field of Search: |
428/626,546,457,553,148,208
205/166
|
References Cited [Referenced By]
U.S. Patent Documents
| 3093501 | Jun., 1963 | Clayton.
| |
| 3918217 | Nov., 1975 | Oliver | 51/295.
|
| 4883703 | Nov., 1989 | Riccio et al. | 428/142.
|
| 4910097 | Mar., 1990 | Nomura et al. | 427/388.
|
| 5443900 | Aug., 1995 | Nagano et al. | 174/35.
|
| 6355313 | Mar., 2002 | Yoshimura et al. | 427/598.
|
| Foreign Patent Documents |
| 1068350 | Jan., 1993 | CN.
| |
| 853998 | Oct., 1952 | DE.
| |
| 25 41 235 | Mar., 1977 | DE.
| |
| 0 406 859 | Jan., 1991 | EP.
| |
| 0 470 610 | Feb., 1992 | EP.
| |
| 806677 | Jan., 1959 | GB.
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| 833037 | Apr., 1960 | GB.
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| 879607 | Oct., 1969 | GB.
| |
| 05090269 | Apr., 1993 | JP.
| |
| 08287724 | Apr., 1995 | JP.
| |
| 7-302705 | Nov., 1995 | JP.
| |
| 2000-133541 | May., 2000 | JP.
| |
Other References
Chinese Office Action dated Aug. 22, 2003 and English translation.
Database, Section Ch, Week 198828, Derwent Publications Ltd.; London, GB:
Class A96, AN 1988-194559, XP002142985 & JP 63 132632, Jun. 4, 1988.
Patent Abstracts of Japan, vol. 1996, No. 3, Mar. 29, 1996 & JP 07-302705 A
(Daido Steel Co. LTD.), Nov. 14, 1995.
Patent Abstract of Japan, vol. 013, No. 485 (M-887), Nov. 6, 1989 & JP 01
192514A (Koito MFG Co., LTD.), Aug. 2, 1989.
"Powder Coating; A Look at Equipment and Materials", by Daniel R. Savage,
"Products Finishing" pp. 40-41, Jan. 1992.
|
Primary Examiner: Jones; Deborah
Assistant Examiner: Sperty; A B
Attorney, Agent or Firm: Armstrong, Kratz, Quintos, Hanson & Brooks, LLP
Parent Case Text
This application is a division of prior application Ser. No. 09/558,162,
filed Apr. 26, 2000 now U.S. Pat. No. 6,365,224.
Claims
What is claimed is:
1. A resin molded product which has a metal layer of a fine metal powder
formed directly on the resin molded surface thereof, wherein tip ends of
particles of the fine metal powder are impaled and forced into the resin
molded surface and portions of the particles protruding on the surface of
the resin molded product are deformed by the process of bringing a fine
metal powder producing material into flowing contact with the resin molded
surface and applying a vibration and/or an agitation to the resin molded
product and the fine metal powder producing material.
2. A resin molded product which has a metal layer of a fine metal powder
formed directly on the resin molded surface thereof, wherein tip ends of
particles of the fine metal powder are impaled and forced into the resin
molded surface and portions of the particles protruding on the surface of
the resin molded product are deformed by the process of bringing a fine
metal powder producing material into flowing contact with the resin molded
surface and applying a vibration and/or an agitation to the resin molded
product and the fine metal powder producing material,
and further comprising a metal plated film formed on said metal layer.
3. A resin molded product according to claim 1, wherein the particles of
the fine metal powder have a particle size of from 0.001 .mu.m to 5 .mu.m.
4. A resin molded product according to claim 2, wherein the particles of
the fine metal powder have a particle size of from 0.001 .mu.m to 5 .mu.m.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for forming, on the surface of a
resin molded product, a metal layer which is useful for forming a metal
film. More particularly, the present invention relates to a process for
forming, on the surface of a resin molded product, a metal layer of a fine
metal powder produced by bringing a metal powder producing material into
flowing contact with the surface of the resin molded product in a treating
vessel.
2. Description of the Related Art
For the purpose of providing, to a resin molded product, various properties
such as an ornamentality, a weather resistance, a surface electrical
conductivity, an electromagnetic wave shielding property, an antibacterial
property and the like, it is a conventional practice to form a metal film
on the surface of the resin molded product. Examples of conventionally
known processes for forming a metal film are a vacuum plating process such
as a vacuum deposition and a sputtering, an electroless plating process,
an electroless plating/electroplating process comprising an electroless
plating step and an electroplating step, and the like. These processes
have been put into practical use in various fields, because an
electroplating process cannot be applied directly to the resin molded
product due to the non-electrical conductivity of the resin molded
product.
However, the vacuum plating process suffers from problems that a metal film
formed by this process has a lower peel strength and a poor durability,
that it is difficult to apply this process to a molded product having a
complicated shape, that a long time is required for the vacuum processing,
because a gas may be generated depending on the type of a resin, and that
a production cost is higher.
The electroless plating process suffers from the following problems: It is
usually necessary to previously subject the surface of a resin molded
product to an etching, or to subject the surface to a catalytic effect
providing process such as a sensitizing/activating process. For this
reason, the steps are complicated; a long time is required for the
processing; and a plated film produced has a small thickness.
In the electroless plating/electroplating process, a metal film formed by
this process has a relatively good peel strength, and a durability which
is remarkably good, as compared with that of a metal film formed by the
vacuum plating process. However, the electroless plating/electroplating
process suffers from problems that the steps are complicated, and that a
long time is required for the processing.
There is also a proposed metal film forming process comprising a step of
applying a resin including a metal powder added thereto to the surface of
a resin molded product to provide an electrical conductivity to the
surface of it, and an electroplating step. However, this process suffers
from a problem that it is generally difficult to provide a resin layer
uniformly on the surface of a resin molded product and for this reason, it
is impossible due to the ununiformity of the resin layer to form a metal
film excellent in thickness accuracy and in surface smoothness.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a process
for forming, on the surface of a resin molded product, a metal layer which
is useful for forming a metal film having an excellent thickness accuracy,
an excellent surface smoothness and a high peel strength on the surface of
the resin molded product in a simple manner.
The present inventors have made various studies to solve the above problems
and as a result, they have found that if a fine metal powder producing
material is brought into flowing contact with the surface of a resin
molded product in a treating vessel, a fine metal powder is produced from
the fine metal powder producing material and forms a firm and high-density
metal layer on the surface of the resin molded product. It has been
further found that the thus-formed metal layer exhibits a function as an
electrically conductive layer and hence, a metal film can be formed in a
simple manner on the surface of the resin molded product by conducting an
electroplating at a subsequent step, and that the metal layer itself
exhibits a function of an ornamentality and the like.
The present invention has been accomplished based on such knowledge. To
achieve the above object, according to a first aspect and feature of the
present invention, there is provided a process for forming a metal layer
on the surface of a resin molded product, comprising the steps of placing
a resin molded product and a fine metal powder producing material into a
treating vessel, and bringing the fine metal powder producing material
into flowing contact with the surface of the resin molded product in the
treating vessel, thereby producing a fine metal powder from the fine metal
powder producing material, and forming a metal layer of the fine metal
powder on the surface of the resin molded product.
According to a second aspect and feature of the present invention, in
addition to the first feature, the fine metal powder producing material is
brought into flowing contact with the surface of the resin molded product
by applying a vibration and/or an agitation to the resin molded product
and the fine metal powder producing material.
According to a third aspect and feature of the present invention, in
addition to the first feature, the treating vessel is a treating chamber
in a barrel finishing machine.
According to a fourth aspect and feature of the present invention, in
addition to the first feature, the processing is carried out in a dry
manner.
According to a fifth aspect and feature of the present invention, in
addition to the first feature, the fine metal powder producing material is
a material for producing a fine powder of at least one metal selected from
the group consisting of Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr and
Al.
According to a sixth aspect and feature of the present invention, in
addition to the first feature, the surface of the resin is previously
roughened at a pre-step.
According to a seventh aspect and feature of the present invention, there
is provided a process for forming a metal film on the surface of a resin
molded product, comprising the steps of forming a metal layer on the
surface of a resin molded product according to any of the first to sixth
features, and forming a metal film on the metal layer.
According to an eighth aspect and feature of the present invention, in
addition to the seventh feature, the metal film is formed by an
electroplating treatment or an electroless plating treatment.
According to a ninth aspect and feature of the present invention, there is
provided a resin molded product which has a metal layer of a fine metal
powder on the surface thereof.
According to a tenth aspect and feature of the present invention, there is
provided a resin molded product which has a metal layer of a fine metal
powder formed on the surface thereof, and a metal film formed on the metal
layer.
With the process for forming a metal layer according to the present
invention, a metal layer of a fine metal powder can be formed at a firmly
and a high density on the surface of the resin molded product. The metal
layer exhibits a function as an electrically conductive layer and hence, a
metal film having an excellent thickness accuracy, an excellent surface
smoothness and a high peel strength can be formed in a simple manner on
the metal layer by conducting an electroplating treatment. In addition, it
is possible for the metal layer itself to exhibit a function of an
ornamentality and the like.
DETAILED DESCRIPTION OF THE INVENTION
The process for forming a metal layer on a resin molded product according
to the present invention comprises the steps of placing a resin molded
product and a fine metal powder producing material into a treating vessel,
and bringing the fine metal powder producing material into flowing contact
with the surface of the resin molded product in the treating vessel,
thereby producing a fine metal powder from the fine metal powder producing
material, and forming a metal layer of the fine metal powder on the
surface of the resin molded product. Therefore, the shape of the resin
molded product is particularly not limited, if it is such that the fine
metal powder producing material can flow on the surface of the resin
molded product.
The present invention is directed to the process for forming the metal
layer on the surface of the resin molded product. Therefore, the term
"resin molded product" used in the present invention means to include, in
addition to a molded product formed of a resin in the whole, a molded
product, only the surface of which is formed of a resin, a molded product
which includes a forming component other than a resin in the inside
thereof, but the surface of which is formed substantially of a resin
(e.g., a bonded magnet, the inside of which is formed of both of a
magnetic powder and a resin, and the surface of which is formed
substantially of a resin) and the like.
Examples of the resins forming the resin molded product are an epoxy resin,
a polyvinyl chloride resin, an acrylic resin, a silicone rubber, a
fluorine resin such as Teflon, an ABS resin
(acrylonitrile-butadiene-styrene terpolymer resin), a polyolefin resin
such as polyethylene and polypropylene, a phenol resin, a polycarbonate, a
polyester resin such as polyethylene terephthalate and polybutylene
terephthalate, a polyimide resin, FRP (fiber-reinforced plastics), a
polyamide resin such as nylons, a thermoplastic elastomer such as a
polyester elastomer and the like.
Examples of the fine metal powder producing materials for producing the
fine metal powder are materials for producing a fine powder of at least
one metal selected from the group consisting of Cu, Sn, Zn, Pb, Cd, In,
Au, Ag, Fe, Ni, Co, Cr and Al. The fine metal powder producing material
may be also a material of an alloy containing any of the above-described
metals. A plurality of fine metal powder producing materials may be used
in combination, so that a metal layer of a desired fine alloy powder
derived from such fine metal powder producing materials is formed on the
resin molded product (For example, a metal layer of a fine Pb-Sn alloy
powder can be formed on the surface of the resin molded product by using a
combination of a fine Pb-powder producing material and a fine Sn-powder
producing material. The resin molded product having such metal layer can
be utilized as an electric contact element in IC). The fine metal powder
producing material may contain impurities inevitable in the industrial
production.
The fine metal powder producing material may comprise metal pieces made of
only a desired metal, composite metal pieces each comprising a desired
metal coated on a core material made of a different metal, and the like.
The pieces may be of any of various shapes such as a needle-like shape (a
wire-like shape), a columnar shape, a massive shape and the like. From the
viewpoint of producing a fine metal powder efficiently, it is desirable to
use metal pieces each with a sharp end, for example, a metal piece having
a needle-like shape and a metal piece having a columnar shape. Such a
desirable shape can be easily provided by employing a known wire cutting
technique.
From the viewpoint of producing a fine metal powder efficiently, the size
(longer diameter) of the pieces of the fine metal powder producing
material is desirably in a range of 0.05 mm to 10 mm, more desirably in a
range of 0.3 mm to 5 mm, and further desirably in a range of 0.5 mm to 3
mm. The fine metal powder producing material comprising pieces having the
same shape and the same size may be used, or the fine metal powder
producing material comprising pieces having different shapes and different
sizes may be used in the form of a mixture.
From the viewpoint of producing a fine metal powder efficiently and the
viewpoint of forming a metal layer of the fine metal powder produced from
the fine metal powder producing material efficiently, it is desirable that
the method for bringing the fine metal powder producing material into
flowing contact with the surface of the resin molded product is a method
which comprises applying a vibration and/or an agitation to the resin
molded product and the fine metal powder producing material. Such method
can be carried out, for example, using a treating chamber in a barrel
finishing machine or a ball mill apparatus. The barrel finishing machine
may be of a known type such as a rotated-type, a vibrated-type, a
centrifugal-type and the like. In the case of the rotated-type, it is
desirable that the rotational speed is in a range of 20 rpm to 50 rpm. In
the case of the vibrated-type, it is desirable that the vibration
frequency is in a range of 50 Hz to 100 Hz, and the vibration amplitude is
in a range of 0.3 mm to 10 mm. In the case of the centrifugal-type, it is
desirable that the rotational speed is in a range of 70 rpm to 200 rpm.
The total amount of resin molded product and fine metal powder producing
material thrown into the treating vessel is desirable to be in a range of
20% by volume to 90% by volume of the internal volume of the treating
vessel. If the total amount is lower than 20% by volume of the internal
volume of the treating vessel, the throughput is too small, which is not
preferred in practical use. On the other hand, if the total amount exceeds
90% by volume of the internal volume of the treating vessel, there is a
possibility that the formation of the metal layer on the surface of the
resin molded product does not occur efficiently. The ratio of the resin
molded product to the fine metal powder producing material thrown into the
treating vessel is desirable to be 3 or less in terms of the volume ratio
(of resin molded product/fine metal powder producing material). If the
volume ratio exceeds 3, there is a possibility that a long time is
required for the formation of the metal layer, which is not preferred in
practical use.
The treating time depends on the throughput, but is generally in a range of
about 1 hour to about 10 hours.
It is desirable that the flowing contact of the fine metal powder producing
material with the surface of the resin molded product is conducted in a
dry manner in consideration of a case where the fine metal powder
producing material is liable to be corroded by oxidation.
The particle size (longer particle diameter) of the fine metal powder
produced from the fine metal powder producing material by the flowing
contact of the fine metal powder producing material with the surface of
the resin molded product is in a range of generally 0.001 .mu.m to
generally 5 .mu.m, and the particles of the fine metal powder are of
various shapes. The particles of the produced fine metal powder are
allowed to collide against the contents (many of which are the pieces of
the fine metal powder producing material) of the treating vessel on the
surface of the resin molded product, whereby tip ends of the particles are
impaled and forced into the surface of the resin molded product, and
portions of the particles protruding on the surface of the resin molded
product are deformed (e.g., spread) to cover the surface. This serves as a
start for the formation of the metal layer and thereafter, the fine metal
particles laminated on the fine metal particles forced into the surface of
the resin molded product, particles resulting from the deformation of the
particles laminated, aggregates of fine metal particles, masses resulting
from the deformation of the aggregates (e.g., scale-shaped masses
resulting from the spreading of the aggregates), laminates of the
aggregates and the like, contribute to the formation of the metal layer,
and all of them form the metal layer. Therefore, it should be understood
that the term "metal layer of the fine metal powder" used in the present
invention means a metal layer formed from a forming source provided by the
fine metal powder produced from the fine metal powder producing material.
For the purpose of assisting the fine metal powder in being forced into the
surface of the resin molded product at an initial stage of the formation
of the metal layer, the surface of the resin molded product may be
previously roughened using an emery abrasive at a pre-step.
The metal layer formed of the fine metal powder in the above manner
exhibits a function as an electrically conductive layer and hence, it is
possible to conduct an electroplating on the metal layer, thereby forming
a metal film having an excellent thickness accuracy and an excellent
surface smoothness on the surface of the resin molded product. Further,
the metal layer has an anchoring effect, because it is formed basically
from the fine metal powder forced into the surface of the resin molded
product. Therefore, the metal film formed on the metal layer has a feature
of a high peel strength. Further, there is an advantage that an
electroless plating treatment can be carried out on the metal layer
without an etching treatment and a catalytic effect providing treatment.
In addition, the metal layer of the fine metal powder according to the
present invention is formed firmly and at a high density on the surface of
the resin molded product. Therefore, the metal layer itself can exhibit
properties such as a corrosion resistance, a wettability, a light
shielding property and the like, in addition to conventionally desired
properties such as an ornamentality and the like by properly selecting a
material for the fine metal powder produced from the fine metal powder
producing material. Additionally, the metal layer can exhibit a plurality
of functions or properties by forming the metal layer in a laminated
manner. It is of course that if a high performance is demanded, it is
necessary to carry out a further electroplating treatment to form a metal
film. From the viewpoint of easily providing given functions or properties
to the resin molded product, however, it is very advantageous that the
metal layer itself can exhibit various functions or properties.
EXAMPLES
Example 1
The following processing was carried out using a 3 cm square block made of
an epoxy resin as a sample. First, the surface of the sample was roughened
by polishing using an emery abrasive of a count of 280. Then, the ten
samples (having an apparent volume of 0.27 liters) having the roughened
surface and a fine Cu-powder producing material (having an apparent volume
of 2 liters) of short columnar pieces (made by cutting a wire) having a
diameter of 2 mm and a length of 2 mm were thrown into a treating chamber
in a vibrated-type barrel finishing machine having a volume of 2.8 liters
(so that the total amount was of 81% by volume of the internal volume of
the treating chamber), where they were treated in a dry manner for 4 hours
under conditions of a vibration frequency of 60 Hz and a vibration
amplitude of 1.5 mm.
A fine Cu powder produced by this operation contained smallest particles
having a longer diameter equal to or smaller than 0.1 .mu.m, and largest
particles having a longer diameter of about 5 .mu.m.
The surface of each of the samples treated was observed by an optical
microscope (having a magnification of 100) and as a result, it was found
that a metal layer of the fine Cu powder could be formed uniformly on the
entire surface of the sample.
Example 2
Each of the samples produced in Example 1 and having the metal layer of the
fine Cu powder on the entire surface was subjected to a ultrasonic washing
for 1 minute and then to an Ni-electroplating treatment in a rack manner
using a plating solution having a composition comprising 240 g/l of nickel
sulfate, 45 g/l of nickel chloride, an appropriate amount of nickel
carbonate (having a pH value regulated) and 30 g/l of boric acid under
conditions of a current density of 2 A/dm.sup.2, a plating time of 60
minutes, a pH value of 4.2 and a bath temperature of 55.degree. C. As a
result, a plated film having a thickness of 15 .mu.m could be formed on
the metal layer made of the fine Cu powder.
Example 3
The following processing was carried out using a 3 cm square block made of
an epoxy resin as a sample. The ten samples (having an apparent volume of
0.27 liters) and a fine Al-powder producing material (having an apparent
volume of 2 liters) of short columnar pieces (made by cutting a wire)
having a diameter of 1 mm and a length of 1 mm were thrown into a treating
chamber in a vibrated-type barrel finishing machine having a volume of 2.8
liters (so that the total amount was of 81% by volume of the internal
volume of the treating chamber), where they were treated in a dry manner
for 4 hours under conditions of a vibration frequency of 60 Hz and a
vibration amplitude of 1.5 mm.
A fine Al powder produced by this operation contained smallest particles
having a longer diameter equal to or smaller than 0.1 .mu.m, and largest
particles having a longer diameter of about 5 .mu.m.
The surface of each of the samples treated was observed by an optical
microscope (having a magnification of 100) and as a result, it was found
that a metal layer of the fine Al powder could be formed uniformly on the
entire surface of the sample.
Example 4
Each of the samples produced in Example 3 and having the metal layer of the
fine Al powder on the entire surface was subjected to a ultrasonic washing
for 1 minute and then immersed in a zincifying solution (having a
composition comprising 50 g/l of sodium hydroxide, 5 g/l of zinc oxide, 2
g/l of ferric chloride, 50 g/l of Rochelle salt and 1 g/l of sodium
nitrate) under a condition of a bath temperature of 20.degree. C. for 1
minute to carryout the zincifying treatment. Then, each of the samples was
washed and subjected to an Ni-electroplating treatment in a rack manner
using a plating solution having a composition comprising 240 g/l of nickel
sulfate, 45 g/l of nickel chloride, an appropriate amount of nickel
carbonate (having a pH value regulated) and 30 g/l of boric acid under
conditions of a current density of 2 A/dm.sup.2, a plating time of 60
minutes, a pH value of 4.2 and a bath temperature of 55.degree. C. As a
result, a plated film having a thickness of 16 .mu.m could be formed on
the metal layer made of the fine Al powder.
Example 5
Each of the samples produced in Example 1 and having the metal layer of the
fine Cu powder on the entire surface was subjected to a ultrasonic washing
for 1 minute and then to an electroless Cu-plating treatment using an
electroless Cu-plating solution (THRUCUP ELC-SP made by Uemura Industries,
Co.) under conditions of a plating time of 30 minutes and a bath
temperature of 60.degree. C. As a result, a plated film having a thickness
of 2 .mu.m could be formed on the metal layer made of the fine Cu powder.
Example 6
The processing was carried out in the same manner as in Example 1, except
that the 3 cm square block made of the epoxy resin used in Example 1 was
replaced by a 3 cm square block made of a polyvinyl chloride resin. As a
result, a metal layer of a fine Cu powder could be formed uniformly on the
entire surface of the block.
Example 7
The processing was carried out in the same manner as in Example 1, except
that the 3 cm square block made of the epoxy resin used in Example 1 was
replaced by a 3 cm square block made of an acrylic resin. As a result, a
metal layer of a fine Cu powder could be formed uniformly on the entire
surface of the block.
Example 8
The processing was carried out in the same manner as in Example 1, except
that the 3 cm square block made of the epoxy resin used in Example 1 was
replaced by a 3 cm square block made of a silicone rubber. As a result, a
metal layer of a fine Cu powder could be formed uniformly on the entire
surface of the block.
Example 9
The processing was carried out in the same manner as in Example 1, except
that the 3 cm square block made of the epoxy resin used in Example 1 was
replaced by a 3 cm square block made of Teflon. As a result, a metal layer
of a fine Cu powder could be formed uniformly on the entire surface of the
block.
Example 10
The processing was carried out in the same manner as in Example 3, except
that the 3 cm square block made of the epoxy resin used in Example 3 was
replaced by a 3 cm square block made of a polyvinyl chloride resin. As a
result, a metal layer of a fine Al powder could be formed uniformly on the
entire surface of the block.
Example 11
The processing was carried out in the same manner as in Example 3, except
that the 3 cm square block made of the epoxy resin used in Example 3 was
replaced by a 3 cm square block made of an acrylic resin. As a result, a
metal layer of a fine Al powder could be formed uniformly on the entire
surface of the block.
Example 12
The processing was carried out in the same manner as in Example 3, except
that the 3 cm square block made of the epoxy resin used in Example 3 was
replaced by a 3 cm square block made of a silicone rubber. As a result, a
metal layer of a fine Al powder could be formed uniformly on the entire
surface of the block.
Example 13
The processing was carried out in the same manner as in Example 3, except
that the 3 cm square block made of the epoxy resin used in Example 3 was
replaced by a 3 cm square block made of Teflon. As a result, a metal layer
of a fine Al powder could be formed uniformly on the entire surface of the
block.
Example 14
70% By volume of a strontium ferrite powder having an average particle size
of 1.22 .mu.m and 30% by volume of a polyester elastomer were mixed in a
henschel mixer and then, the mixture was subjected to a molding in a
twin-screw extruder, thereby producing a bonded magnet having a size of 10
mm.times.10 mm.times.100 mm and having a surface formed substantially of
the polyester elastomer. The surface of the bonded magnet was roughened by
polishing using an emery abrasive having a count of 280. Then, the 20
bonded magnets (having an apparent volume of 0.2 liters) having the
roughened surface and a fine Cu-powder producing material (having an
apparent volume of 2 liters) of short columnar pieces (made by cutting a
wire) having a diameter of 2 mm and a length of 2 mm were thrown into a
treating chamber in a vibrated-type barrel finishing machine having a
volume of 2.8 liters (so that the total amount was of 79% by volume of the
internal volume of the treating chamber), where they were treated in a dry
manner for 4 hours under conditions of a vibration frequency of 60 Hz and
a vibration amplitude of 1.5 mm.
A fine Cu powder produced by this operation contained smallest particles
having a longer diameter equal to or smaller than 0.1 .mu.m, and largest
particles having a longer diameter of about 5 .mu.m.
The surface of each of the bonded magnets was observed by an optical
microscope (having a magnification of 100) and as a result, it was found
that a metal layer of the fine Cu powder could be formed uniformly on the
entire surface of the bonded magnet.
Example 15
Each of the bonded magnets produced in Example 14 and having the metal
layer of the fine Cu powder on the entire surface was subjected to an
Ni-electroplating treatment under the same conditions as in Example 2. As
a result, a plated film having a thickness of 13 .mu.m could be formed on
the metal layer made of the fine Cu powder.
The metal layer made of the fine Cu powder formed on the entire surface of
the bonded magnet having the surface formed substantially of the polyester
elastomer in the above manner is useful as a primary coat layer for an
electroplating treatment of the bonded magnet. An effect of enhancing the
mechanical strength of the magnet (preventing the cracking and breaking)
was provided by forming a plated film on the surface of the metal layer by
an electroplating treatment, whereby the generation of a magnetic fine
powder due to the cracking and breaking of the magnet could be prevented.
Example 16
65% By volume of MQP-B (which is a trade name and made by MQI, Co.) made by
pulverization of a rapid solidified thin band of an R-Fe-B based alloy and
35% by volume of nylon-12 were mixed in a henschel mixer and then, the
mixture was subjected to a molding in an injection molding machine,
thereby producing a bonded magnet having a size of 10 mm.times.10
mm.times.10 mm and having a surface formed substantially of the nylon-12.
The surface of the bonded magnet was roughened by polishing using an emery
abrasive having a count of 280. Then, the 100 bonded magnets (having an
apparent volume of 0.1 liter) having the roughened surface and a fine
Cu-powder producing material (having an apparent volume of 2 liters) of
short columnar pieces (made by cutting a wire) having a diameter of 2 mm
and a length of 2 mm were thrown into a treating chamber in a
vibrated-type barrel finishing machine having a volume of 2.8 liters (so
that the total amount was of 75% by volume of the internal volume of the
treating chamber), where they were treated in a dry manner for 4 hours
under conditions of a vibration frequency of 60 Hz and a vibration
amplitude of 1.5 mm.
A fine Cu powder produced by this operation contained smallest particles
having a longer diameter equal to or smaller than 0.1 .mu.m, and largest
particles having a longer diameter of about 5 .mu.m.
The surface of each of the bonded magnets was observed by an optical
microscope (having a magnification of 100) and as a result, it was found
that a metal layer of the fine Cu powder could be formed uniformly on the
entire surface of the bonded magnet.
Example 17
Each of the bonded magnets produced in Example 16 and having the metal
layer of the fine Cu powder on the entire surface was subjected to an
Ni-electroplating treatment under the same conditions as in Example 2. As
a result, a plated film having a thickness of 14 .mu.m could be formed on
the metal layer made of the fine Cu powder.
The metal layer made of the fine Cu powder formed on the entire surface of
the bonded magnet having the surface formed substantially of the nylon-12
in the above manner is useful as a primary coat layer for an
electroplating treatment of the bonded magnet. An effect of enhancing the
weather resistance and the mechanical strength of the magnet (preventing
the cracking and breaking) could be provided by forming a plated film on
the surface of the metal layer by an electroplating treatment.
Example 18
The processing was carried out in the same manner as in Example 1, except
that the 3 cm square block made of the epoxy resin used in Example 1 was
replaced by a 3 cm square block made of FRP (a fiber-reinforced plastics).
As a result, a metal layer of a fine Cu powder could be formed uniformly
on the entire surface of the block.
Example 19
The following processing was carried out using a 3 cm square block made of
an epoxy resin as a sample. First, the surface of the sample was roughened
by polishing using an emery abrasive of a count of 280. Then, the ten
samples (having an apparent volume of 0.27 liters) having the roughened
surface and a fine Ni-powder producing material (having an apparent volume
of 2 liters) of short columnar pieces (made by cutting a wire) having a
diameter of 2 mm and a length of 2 mm were thrown into a treating chamber
in a vibrated-type barrel finishing machine having a volume of 2.8 liters
(so that the total amount was of 81% by volume of the internal volume of
the treating chamber), where they were treated in a dry manner for 4 hours
under conditions of a vibration frequency of 60 Hz and a vibration
amplitude of 1.5 mm.
A fine Ni powder produced by this operation contained smallest particles
having a longer diameter equal to or smaller than 0.1 .mu.m, and largest
particles having a longer diameter of about 5 .mu.m.
The surface of each of the samples treated was observed by an optical
microscope (having a magnification of 100) and as a result, it was found
that a metal layer of the fine Ni powder could be formed uniformly on the
entire surface of the sample.
Example 20
Each of the samples produced in Example 19 and having the metal layer of
the fine Ni powder on the entire surface was subjected to a ultrasonic
washing for 1 minute and then to an electroless Ni-plating treatment using
an electroless Ni-plating solution (NIMUDEN SX made by Uemura Industries,
Co.) under conditions of a plating time of 30 minutes and a bath
temperature of 90.degree. C. As a result, a plated film having a thickness
of 4 .mu.m could be formed on the metal layer made of the fine Ni powder.
Then, the resulting sample was subjected to an Ni-electroplating treatment
under the same conditions as in Example 2, and as a result, a plated film
having a thickness of 15 .mu.m could be formed in a laminated manner.
*
