U.S. patent application number 12/519896 was filed with the patent office on 2010-12-02 for composite of metal and resin and method for manufacturing the same.
This patent application is currently assigned to TAISEI PLAS CO., LTD.. Invention is credited to Naoki Andoh, Masanori Naritomi.
Application Number | 20100304083 12/519896 |
Document ID | / |
Family ID | 39562503 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100304083 |
Kind Code |
A1 |
Naritomi; Masanori ; et
al. |
December 2, 2010 |
COMPOSITE OF METAL AND RESIN AND METHOD FOR MANUFACTURING THE
SAME
Abstract
It is an object of the present invention to securely and
integrally join a metal and a resin, more particularly, a shaped
titanium alloy substrate and a resin composition. A titanium alloy
substrate is used that has undergone surface roughening by chemical
etching or the like so as to have a ultrafine textured face in
which bent, ridge-like protrusions having a width and height of
from ten to a few hundred nanometers and a length of from a few to
a few hundred microns rise up on the surface at a spacing period of
from ten to a few hundred nanometers. A titanium alloy piece 1 with
its surface treated is inserted into the cavity of a metallic mold
for injection molding 10 and a specific resin composition 4 is
injected to obtain an integrated composite 7. The main resin
component of the resin composition 4 that is used can be a
polyphenylene sulfide resin (PPS) or a polybutylene terephthalate
resin (PBT). High injection joining strength is obtained if the
resin composition contains, as an auxiliary component, a
polyethylene terephthalate resin and/or polyolefin resin in the
case of PBT and a polyolefin resin in the case of PPS.
Inventors: |
Naritomi; Masanori; (Tokyo,
JP) ; Andoh; Naoki; (Tokyo, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW, SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
TAISEI PLAS CO., LTD.
Tokyo
JP
|
Family ID: |
39562503 |
Appl. No.: |
12/519896 |
Filed: |
December 21, 2007 |
PCT Filed: |
December 21, 2007 |
PCT NO: |
PCT/JP2007/074749 |
371 Date: |
October 19, 2009 |
Current U.S.
Class: |
428/141 ;
216/53 |
Current CPC
Class: |
Y10T 428/24355 20150115;
B29K 2705/02 20130101; B29C 45/14221 20130101; B29C 2045/14868
20130101; B29K 2081/04 20130101; B29C 45/14311 20130101; C23F 1/26
20130101; B29C 70/683 20130101; B29C 45/14008 20130101; B29K
2705/00 20130101; B29K 2067/006 20130101; B29K 2705/08 20130101;
B29C 2045/14245 20130101 |
Class at
Publication: |
428/141 ;
216/53 |
International
Class: |
B32B 15/085 20060101
B32B015/085; B32B 15/08 20060101 B32B015/08; B29C 45/14 20060101
B29C045/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2006 |
JP |
2006-345273 |
Claims
1. A composite of metal and resin, comprising: a titanium alloy
substrate that has been machined into a specific shape and then
chemically etched so as to have an ultrafine textured face in which
bent, ridge-like protrusions having a width and height of from ten
to a few hundred nanometers and a length of from a few to a few
hundred microns rise up on the surface at a spacing period of from
ten to a few hundred nanometers and so as to have a surface in
which a surface roughness with a mean width of profile elements
(RSm) of 1 to 10 .mu.m and a maximum height of roughness (Rz) of
0.5 to 5 .mu.m is observed; and a first resin composition whose
main component is a polyphenylene sulfide resin or a second resin
composition whose main component is a polybutylene terephthalate
resin, which is directly joined by injection molding to the
titanium alloy substrate.
2. A composite of metal and resin, comprising: a titanium alloy
substrate that has been machined into a specific shape and then
chemically etched so as to have a surface in which a surface
roughness with a mean width of profile elements (RSm) of 1 to 10
.mu.m and a maximum height of roughness (Rz) of 0.5 to 5 .mu.m is
observed and so as to have a ultrafine textured face in which are
observed both smooth dome-like shapes and dead leaf-like shapes
within a surface area measuring 10 .mu.m square; and a first resin
composition whose main component is a polyphenylene sulfide resin
or a second resin composition whose main component is a
polybutylene terephthalate resin, which is directly joined by
injection molding to the titanium alloy substrate.
3. The composite of metal and resin according to any of claim 1 or
2, wherein the resin component of said first resin composition is a
resin composition in which the polyphenylene sulfide resin is the
main component and a polyolefin resin is an auxiliary
component.
4. The composite of metal and resin according to any of claim 1 or
2, wherein the resin component of said second resin composition is
a resin composition in which the polybutylene terephthalate resin
is the main component and a polyethylene terephthalate resin and/or
a polyolefin resin is an auxiliary component.
5. The composite of metal and resin according to any of claims 1 to
4, wherein the surface of said substrate is covered with a thin
film that is thicker than a natural oxidized film.
6. The composite of metal and resin according to claim 5, wherein
said thin film is of titanium oxide.
7. The composite of metal and resin according to claim 3, wherein
said first resin composition contains polyphenylene sulfide resin
by 70 to 97 wt % and polyolefin resin by 3 to 30 wt %.
8. The composite of metal and resin according to claim 4, wherein
said second resin composition contains polybutylene terephthalate
resin by 70 to 97 wt % and polyethylene terephthalate resin and/or
polyolefin resin by 3 to 30 wt %.
9. The composite of metal and resin according to any of claims 1 to
8, wherein said first resin composition or said second resin
composition contains at least one type of filler selected from
among glass fiber, carbon fiber, aramid fiber, other reinforcing
fiber, calcium carbonate, magnesium carbonate, silica, talc, clay
and glass powder, in an amount of 20 to 60 wt %.
10. A method for manufacturing a composite of metal and resin,
comprising: a shaping step of shaping a titanium alloy substrate by
mechanical working; a surface treatment step including chemical
etching for providing the surface of said shaped substrate with a
ultrafine textured face in which protrusions with a height, width
and length of at least 10 nm rise up at a spacing period of at
least 10 nm in observation with an electron microscope and which a
surface roughness made up of the textured face with a maximum
height of roughness of 0.5 to 5 .mu.m at a period of 1 to 10 .mu.m;
an insertion step of inserting said substrate that has undergone
said surface treatment including chemical etching into a metallic
mold for injection molding; and an integrating step of injecting a
first resin composition or a second resin composition onto said
inserted substrate and integrating said substrate with said first
resin composition or said second resin composition, said first
resin composition being one in which a polyphenylene sulfide resin
is the main component and a polyolefin resin is an auxiliary
component, and said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
11. A method for manufacturing a composite of metal and resin,
comprising: a shaping step of shaping a titanium alloy substrate by
mechanical working; a surface treatment step including chemical
etching for providing the surface of said shaped substrate with a
ultrafine textured face in which are observed both smooth dome-like
shapes and dead leaf-like shapes within a surface area measuring 10
.mu.m square and which a surface roughness with mean width of
profile elements (RSm) of 1 to 10 .mu.m and maximum height of
roughness (Rz) of 1 to 5 .mu.m in observation with a scanning probe
microscope; an insertion step inserting said substrate that has
undergone said surface treatment including chemical etching into an
metallic mold for injection molding; and an integrating step of
injecting a first resin composition or a second resin composition
onto said inserted substrate and integrating said substrate with
said first resin composition or said second resin composition, said
first resin composition being one in which a polyphenylene sulfide
resin is the main component and a polyolefin resin is an auxiliary
component, and said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
12. A method for manufacturing a composite of metal and resin,
comprising: a shaping step of shaping a titanium alloy substrate by
mechanical working; a chemical etching step of immersing said
shaped substrate in an aqueous solution containing ammonium
monohydrodifluoride and rinsing the same with water; an insertion
step of inserting said chemically etched substrate into a metallic
mold for injection molding; and an integration step of injecting a
first resin composition or a second resin composition onto said
inserted substrate and integrating said substrate with said first
resin composition or said second resin composition, said first
resin composition being one in which a polyphenylene sulfide resin
is the main component and a polyolefin resin is an auxiliary
component, and said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a composite of a metal
part, particularly one made of a titanium alloy, and a resin molded
article, which is used for housings of electronic equipments,
housings of consumer electrical equipments, mechanical parts and so
forth and to a method for manufacturing this composite. More
particularly, the present invention relates to a composite, in
which a thermoplastic resin composition is integrated with a
titanium alloy part made by mechanical working, and to a method for
manufacturing this composite and also relates to a composite of
metal and resin, which is favorable for use in various mobile
electronic equipments, consumer electrical products, medical
instruments, automotive structural parts, automotive mounted
equipments, other electrical parts and in corrosion resistant
exterior trim parts or the like and to a method for manufacturing
the composite.
BACKGROUND OF THE INVENTION
[0002] Technology for integrating metals and resins is needed in
many different fields of industry, such as in manufacturing of
parts for automobiles, consumer electrical products, industrial
machinery or the like and many adhesive agents have been developed
for this purpose. Some very excellent adhesives have been proposed.
For example, adhesives that exhibit their function at normal
temperature or with heating are used to integrally join metals and
synthetic resins and this method is currently a common joining
technique.
[0003] On the other hand, more rational joining methods that do not
involve the use of an adhesive have been studied heretofore. An
example is a method in which a high-strength engineering plastic is
integrated with a light metal such as magnesium, aluminum, an alloy
of these or an iron alloy such as stainless steel without the use
of an adhesive. For instance, the inventors proposed a method in
which a molten resin is injected onto a metal part that was
inserted preliminarily into a metallic mold for injection molding,
thereby forming a resin part and at the same time this molded
article and the metal parts are joined (hereinafter this will be
referred to as "injection joining").
[0004] Known technology related to this injection joining is a
manufacturing technique in which a polybutylene terephthalate resin
(hereinafter referred to as PBT) or a polyphenylene sulfide resin
(hereinafter referred to as PPS) is joined by injection joining to
an aluminum alloy (see Japanese Patent Application Laid-Open No.
2004-216425: Patent Document 1, for example). A joining technique
has also been disclosed in which somewhat large holes are made in
an anodized film on a piece of aluminum and a synthetic resin is
made to penetrate into these holes and adjoined thereto (see
WO/2004-055248-A1: Patent Document 2, for example).
[0005] The principle behind this injection joining in Patent
Document 1 is as follows. An aluminum alloy is immersed in a dilute
aqueous solution of a water-soluble amine compound, the aluminum
alloy is finely etched with a weakly basic aqueous solution and at
the same time the amine compound molecules are adsorbed to the
surface of the aluminum alloy. After undergoing this treatment, the
aluminum alloy is inserted in a metallic mold for injection molding
and a molten thermoplastic resin is injected under high
pressure.
[0006] Here, the amine compound molecules adsorbed to the surface
of the aluminum alloy encounter the thermoplastic resin and heat is
generated. At substantially the same time as this heat generation,
the thermoplastic resin is quenched by coming into contact with the
aluminum alloy that is held at a mold temperature which is lower
than the melting temperature of the thermoplastic resin. The resin
that was apt to be crystallized and solidified here is not
crystallized as quickly because of the generated heat and gets into
ultrafine recesses on the aluminum alloy surface. Consequently,
with the composite of aluminum alloy and thermoplastic resin, the
resin is securely joined (fixed) to the aluminum alloy and is not
separated from the aluminum alloy surface. That is, when an
exothermic reaction occurs, a strong injection joint is produced.
It has actually been confirmed that PBT or PPS, which can undergo a
chemical reaction with an amine compound, can be joined by
injection joining to an aluminum alloy. Another well known
technique involves chemically etching the surface of a metal part
preliminarily, then inserting the metal part into the mold of an
injection molding machine and performing injection molding with a
thermoplastic resin material (see Japanese Patent Application
Laid-Open No. 2001-225352: Patent Document 3, for example).
[0007] However, although the joining principle in Patent Document 1
by the inventors does exhibit an extremely good effect with
aluminum alloys or the like, it has not effect in injection joining
to other metals besides aluminum alloys. Accordingly, there has
been a need for the development of a novel technique for joining
metals and resins. The inventors discovered such a novel technique
in the course of making improvements to their method for joining a
hard resin by injection joining to an aluminum alloy. Specifically,
conditions were discovered under which injection joining will be
possible without any chemical adsorption of the amine compound to
the metal part surface or, in other words, without the help of a
special exothermic reaction or any particular chemical
reaction.
[0008] At least two conditions are necessary. The first condition
is that a hard resin of high crystallinity be used, that is, that
PPS, PBT or an aromatic polyamide be used and, furthermore, that
these be suited to injection joining to obtain a further improved
composition. Another condition is that the surface layer of the
metal part have a suitably rough shape and that the surface be
hard.
[0009] For example, when a shaped material in which a magnesium
alloy serves as the material is used, corrosion resistance is low
for a magnesium alloy still covered with a natural oxidized film,
so a surface covered with a hard ceramic material can be obtained
by subjecting this to chemical conversion treatment or electrolytic
oxidation treatment and converting the surface layer into a metal
oxide, a metal carbonate or a metal phosphorus oxide. Magnesium
alloy parts having these surface layers come close to meet the
above-mentioned conditions.
[0010] Theoretically, these shaped magnesium alloys with their
surface treated are considered as follows, assuming that they are
inserted into a metallic mold for injection molding. The mold and
the inserted shaped magnesium alloy are generally held at a
temperature lower than the melting point of the resin being
injected by at least a hundred and several tens of degrees, so
there is a high possibility that the temperature of the injected
resin may have dropped below its melting point at the time when it
is quenched upon entering the channel inside the mold and comes
into contact with magnesium alloy part.
[0011] Regardless of the crystalline resin, when it is rapidly
cooled to below its melting point, it does not become crystallized
and solidified immediately (that is, in zero time) and there is
some time, albeit extremely short, for the resin to remain in a
molten state below the melting temperature or, in other words, in a
super-cooled state. If the recesses in the shaped alloy are
relatively large with a diameter of several hundred nanometers,
then it is possible that the molten resin penetrates into these
recesses within the limited time from a super-cooled state to
creation of microcrystals. To put this in another way, if the
numerical density of the macromolecular microcrystal group that is
produced is still low, then the resin can sufficiently penetrate
into the recesses as long as the recesses are large with an inside
diameter of several hundred nanometers. This is because the size of
the microcrystals, specifically microcrystals in which a molecular
chain behaving irregularly has undergone a change into some kind of
state with order in the molecular chain, is considered to be from
several nanometers to 10 nm, as estimated from a molecular
model.
[0012] Consequently, although the penetration of microcrystals into
ultrafine recesses with a diameter of 20 to 30 nm cannot be
considered a simple matter, it is concluded that the microcrystals
can penetrate as long as the recesses have a diameter of about
several hundred nanometers. However, since countless microcrystals
are simultaneously generated, the viscosity of the resin flow rises
abruptly at the distal end of the injected resin and at places in
contact with the mold metal faces. Therefore, if the recesses have
a diameter of about 100 nm, the resin may not be able to penetrate
all the way to the bottom but will be crystallized and solidified
after penetrating considerably into the interior, so fairly good
joint strength (fixing strength) is produced. Here, even if the
surface of the shaped magnesium alloy is an amorphous layer or a
ceramic microcrystal group such as a metal oxide, the resin will be
securely anchored within the recesses, provided that the surface
layer is hard and strong and has a textured face on the nanometer
order, hence, the solidified and crystallized resin will not
readily come out of the recesses, which means that joint strength
is improved. This textured face on the nanometer order presents a
coarse surface as a visual image viewed with an electron
micrograph.
[0013] Improving the resin composition that is injected is actually
the most important element in the present invention. This
relationship will be described. When the resin composition is
molded for injection molding, it is quenched from a molten state to
a temperature below its melting point and attempts to be
crystallized and solidified, where a resin composition that is
crystallized slowly can afford better joint strength. This is a
requirement for resin compositions that are suitable for injection
joining.
[0014] Based on this, the inventors proposed a technique in which a
shaped magnesium alloy is chemically etched and then subjected to
chemical conversion treatment or another such surface treatment as
mentioned above to make the surface layer ceramic, which allows a
hard crystalline resin to be joined by injection joining to this
and high joinability to be obtained (Japanese Patent Application
Laid-Open No. 2007-301972). This proves the possibility of
injection joining even without the chemical adsorption of an amine
compound and, when horizontal development is taken into account,
also suggests that injection joining can be performed using a PBT
or PPS that has been improved for injection joining, as long as at
least surface configuration and surface properties are the same for
all metals and metal alloys.
[0015] Let us now describe what has been disclosed as prior art.
Patent Document 3 discloses a method in which chemically etched
copper wire is inserted into a metallic mold for injection molding
and PPS or the like is injected to produce a lead wire-equipped
battery cover having a shape such that several copper wires pass
through the middle portion of a PPS disk. According to the
technology, even if the internal pressure of the battery rises due
to the bumps (roughness) on the surface of the copper wire formed
by chemical etching, gas will not leak out through the lead wire
part.
[0016] The technology disclosed in Patent Document 3 is not the
injection joining technology insisted by the inventors but is
instead technology that is an extension of existing injection
molding technology and is merely one that utilizes the difference
in the linear coefficient of expansion of metals and the molding
shrinkage of resins. If a resin is injected into the peripheral
portion of the structure in which a metal rod-like piece passes
through the resin portion, then the molded article is parted from
the mold and allowed to be cooled, the rod-like piece is in a
situation of being pressed by the surrounding molded resin portion.
The reason is that the linear coefficient of expansion of a metal
is at most 1.7 to 2.5.times.10.sup.-5.degree. C..sup.-1 for an
aluminum alloy, magnesium alloy, copper or copper alloy and, even
if the molded article has been removed from the mold and cooled to
room temperature, the shrinkage of metal will be on the level of
the linear coefficient of expansion multiplied by about 100.degree.
C. and will be no more than 0.2 to 0.3%.
[0017] Further, the object of the technology is to keep gas from
leaking out through the joint between the metal and the resin and
the technology is premised on the fact that substantially a slight
gap is formed, while it is not specifically aimed in the technology
to secure the two parts. In other words, it is essential there that
a labyrinth effect prevents gas from easily leaking out.
Furthermore, concerning with a resin, the molding shrinkage is
about 1% for PPS, 0.5% for PPS containing glass fiber and, even for
a resin in which the filler content has been increased, the resin
part will always shrink more than the metal part after injection
molding. Therefore, if a shaped article in which the metal part is
disposed in the center and this metal part goes through the resin
part is produced by injection molding with an insert, an integrated
product can be manufactured in which the metal part is not likely
to come loose due to the pressing effect produced by molding
shrinkage of the resin portion.
[0018] This method for manufacturing an integrated metal and resin
product by pressing effect is known conventionally and is used to
fabricate a knob on fuel oil stove as an example of a similar
molded article. This method involves inserting a thick iron needle
with a diameter of about 2 mm into a metallic mold for injection
molding and injecting a heat resistant resin or the like into the
mold. Jagged cuts (such as knurling) are formed around the needle
and the resin is fixed to this so that there may be no movement. In
the technology disclosed in Patent Document 3, the texturing
process is changed from a physical process to a chemical process,
which makes the working process simple as well as the bumps finer
and improves gripping effect by using mainly a resin that is hard
and crystalline for the resin part.
[0019] With the present invention there is no need at all for a
pressing effect of resin. A powerful force is required to break an
article in which flat plates have been joined. If the joined state
of the metal and thermoplastic resin is to be maintained stably
over an extended period, it is actually necessary for the linear
coefficients of expansion of the two materials to be close in
values. The linear coefficient of expansion of a thermoplastic
resin composition can be lowered considerably by containing a large
amount of glass fiber, carbon fiber or other such reinforcing
fiber, where the limit to this is 2 to 3.times.10.sup.-5.degree.
C..sup.-1. Kinds of metals that approach this value at close to
normal temperature are aluminum, magnesium, copper and silver.
[0020] The present invention is related to a technology that makes
it possible for a hard resin to be joined by injection joining to a
titanium alloy. The linear coefficient of expansion of a titanium
alloy is about 0.9.times.10.sup.-5.degree. C..sup.-1, which is
lower than half value of the above-mentioned metal group. In this
sense, research and development into injection joining conducted by
the inventors were put aside but it seemed to be very likely that
success would be possible if the temperature range for use were
narrower, so research and development into titanium alloys were
conducted. If it could be confirmed that injection joining was
possible with titanium alloys according to the above-mentioned
hypothesis of the inventors, then this would prove that the
hypothesis is correct.
[0021] The specific gravity of a titanium alloy is about 4.5, which
is about 60% that of iron (specific gravity of 7.9), but titanium
alloys are on a par with iron and iron alloys in terms of hardness
and strength and are used as high-strength, lightweight metals.
Titanium alloys also resist chlorine ions, as in case of salt water
or sea water, and have exceedingly good corrosion resistance in
outdoor applications. Therefore, titanium alloy parts are
frequently used in various mobile electronic equipment, medical
instruments, automotive mounted equipments, automobile parts,
marine machineries, other such parts used in movable devices and
particularly in the casings and housings of equipments that may be
exposed to drops of salt water or sea water. The required
mechanical fixing strength and durability can be ensured and,
furthermore, when a hard resin is injected onto a titanium alloy,
the production of these equipment casings is considered to be
extremely easy. Moreover, titanium alloys do not irritate skin or
body. These alloys are therefore known to be extremely important as
metals that are accepted by body and are used for prosthetic legs
and hands, for example.
[0022] Let us review the conditions important for the injection
joining of metals and resins by summing the hypothesis by the
inventors. Specifically, to obtain good injection joining strength,
it is necessary at least on the shaped metal side:
[0023] (1) that the surface have large bumps (roughness) obtained
by chemical etching and that the period thereof be at least a few
hundred nanometers, preferably at least 1 .mu.m and even more
preferably have a mean bump period of 1 to 10 .mu.m;
[0024] (2) that the surface have an ultrafine textured face on the
nanometer order so that it may be sufficiently hard and non-slip,
that is, that the surface look coarse when viewed microscopically;
and
[0025] (3) that a high-hardness, crystalline resin can be used as
the resin, while preferably a resin composition that has been
improved so as to delay crystallization during quenching.
[0026] This hypothesis proved to hold true not only for magnesium
alloys but also for copper and copper alloys. The coarse surface
mentioned in (2) above is a level that can only be observed with an
electron microscope and to put this more as a general rule, high
injection joining strength can be obtained when the spacing period
is 10 to 500 nm and the height and/or depth is at least 10 nm.
SUMMARY OF THE INVENTION
[0027] The present invention has been conceived in light of the
technical background discussed above and achieves the following
object.
[0028] It is an object of the present invention to provide a metal
and resin composite, in which a resin is joined by injection
joining to a piece of shaped titanium alloy and a high joint
strength is obtained, as well as a method for manufacturing the
composite.
[0029] It is another object of the present invention to provide a
metal and resin composite, in which joinability is improved by
injection joining between a shaped titanium alloy with its surface
treated and a high-hardness crystalline resin composition, as well
as a method for manufacturing the composite.
[0030] The present invention employs the following means to achieve
the stated object. Specifically, the composite of metal and resin
according to the present invention 1 is composed of:
[0031] a titanium alloy substrate that has been machined into a
specific shape and then chemically etched so as to have an
ultrafine textured face in which bent, ridge-like protrusions
having a width and height of from ten to a few hundred nanometers
and a length of from a few to a few hundred microns rise up on the
surface at a spacing period of from ten to a few hundred nanometers
and so as to have a surface in which a surface roughness with a
mean width of profile elements (RSm) of 1 to 10 .mu.m and a maximum
height of roughness (Rz) of 0.5 to 5 .mu.m is observed; and
[0032] a first resin composition whose main component is a
polyphenylene sulfide resin or a second resin composition whose
main component is a polybutylene terephthalate resin, which is
directly joined by injection molding to the titanium alloy
substrate.
[0033] The composite of metal and resin according to the present
invention 2 is composed of:
[0034] a titanium alloy substrate that has been machined into a
specific shape and then chemically etched so as to have a surface
in which a surface roughness with a mean width of profile elements
(RSm) of 1 to 10 .mu.m and a maximum height of roughness (Rz) of
0.5 to 5 .mu.m is observed and so as to have a ultrafine textured
face in which are observed both smooth dome-like shapes and dead
leaf-like shapes within a surface area measuring 10 .mu.m square;
and
[0035] a first resin composition whose main component is a
polyphenylene sulfide resin or a second resin composition whose
main component is a polybutylene terephthalate resin, which is
directly joined by injection molding to the titanium alloy
substrate.
[0036] The method for manufacturing a composite of metal and resin
according to the present invention 10 comprises:
[0037] a shaping step of shaping a titanium alloy substrate by
mechanical working;
[0038] a surface treatment step including chemical etching for
providing the surface of said shaped substrate with a ultrafine
textured face in which protrusions with a height, width and length
of at least 10 nm rise up at a spacing period of at least 10 nm in
observation with an electron microscope and which a surface
roughness made up of the textured face with a maximum height of
roughness of 0.5 to 5 .mu.m at a period of 1 to 10 .mu.m;
[0039] an insertion step of inserting said substrate that has
undergone said surface treatment including chemical etching into a
metallic mold for injection molding; and
[0040] an integrating step of injecting a first resin composition
or a second resin composition onto said inserted substrate and
integrating said substrate with said first resin composition or
said second resin composition,
[0041] said first resin composition being one in which a
polyphenylene sulfide resin is the main component and a polyolefin
resin is an auxiliary component, and
[0042] said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
[0043] The method for manufacturing a composite of metal and resin
of present invention 11 comprises:
a shaping step of shaping a titanium alloy substrate by mechanical
working;
[0044] a surface treatment step including chemical etching for
providing the surface of said shaped substrate with a ultrafine
textured face in which are observed both smooth dome-like shapes
and dead leaf-like shapes within a surface area measuring 10 .mu.m
square and which a surface roughness with mean width of profile
elements (RSm) of 1 to 10 .mu.m and maximum height of roughness
(Rz) of 1 to 5 .mu.m in observation with a scanning probe
microscope;
[0045] an insertion step inserting said substrate that has
undergone said surface treatment including chemical etching into an
metallic mold for injection molding; and
[0046] an integrating step of injecting a first resin composition
or a second resin composition onto said inserted substrate and
integrating said substrate with said first resin composition or
said second resin composition,
[0047] said first resin composition being one in which a
polyphenylene sulfide resin is the main component and a polyolefin
resin is an auxiliary component, and
[0048] said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
[0049] The method for manufacturing a composite of metal and resin
of present invention 12 comprises:
[0050] a shaping step of shaping a titanium alloy substrate by
mechanical working;
[0051] a chemical etching step of immersing said shaped substrate
in an aqueous solution containing ammonium monohydrodifluoride and
rinsing the same with water;
[0052] an insertion step of inserting said chemically etched
substrate into a metallic mold for injection molding; and
[0053] an integration step of injecting a first resin composition
or a second resin composition onto said inserted substrate and
integrating said substrate with said first resin composition or
said second resin composition,
[0054] said first resin composition being one in which a
polyphenylene sulfide resin is the main component and a polyolefin
resin is an auxiliary component, and
[0055] said second resin composition being one in which a
polybutylene terephthalate resin is the main component and a
polyethylene terephthalate resin and/or a polyolefin resin is an
auxiliary component.
[0056] Surface roughness can be automatically measured using, for
example, a scanning probe microscope. Surface roughness refers to
the surface profile and can be displayed by a roughness profile,
which is one of the curves representing the surface profile. This
roughness profile is defined by the mean width of the profile
elements (RSm) and the maximum height of roughness profile (Rz).
These numerical values are specified by the Japan Industrial
Standard (JIS B 0601: 2001). This Japan Industrial Standard (JIS B
0601: 2001) was produced in such a manner that ISO 4287 issued in
1997 was translated into Japanese without changing the technical
content or specification table format. The above-mentioned
ultrafine textured face was measured by observation with an
electron microscope in magnification of 100,000 times. Further, the
ultrafine textured shape, in which both the dome-like shapes and
dead leaf-like shapes were seen, was observed within a surface area
measuring 10 .mu.m square with an electron microscope in
magnification of 10,000 times.
APPLICABLE INDUSTRIAL FIELD
[0057] Applying the present invention in various fields affords
better joinability, higher efficiency, an expanded range of
application and so forth and makes possible the rationalization of
manufacturing and the enhancement of corrosion resistance in the
cases of electronic equipments and consumer electrical equipments.
As a result, the present invention can contribute to better
productivity and performance for casings and parts used in mobile
electronic equipments, mounted electrical and electronic
equipments, marine-use electrical and electronic equipments and in
many other industrial fields.
EFFECTIVENESS
[0058] As explained in detail above, with the composite according
to the present invention, a resin composition part and a titanium
alloy part are integrated so that they may not readily come apart.
A thermoplastic resin composition having a resin component
containing PBT by 70 to 97 wt % and PET and/or polyolefin resin by
3 to 30 wt % or a thermoplastic resin composition having a resin
component containing PPS by 70 to 97 wt % and polyolefin resin by 3
to 30 wt % can be securely joined by injection joining to a
titanium alloy substrate that has undergone a specific surface
treatment and, as a result, a composite can be manufactured in
which a resin and a titanium alloy are integrated. Moreover, the
method for manufacturing the composite is based on the joining
technology to which the injection molding technology with good
productivity is applied and the productivity of parts and casings
in which titanium alloys are used can be improved with this
method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] FIG. 1 is a cross sectional view schematically illustrating
a metallic mold for manufacturing a composite of metal and resin (a
titanium alloy substrate and a resin composition);
[0060] FIG. 2 is an exterior view schematically illustrating a
composite of metal and resin (a titanium alloy substrate and a
resin composition);
[0061] FIG. 3 is a photograph as a result of observation with an
electron microscope in magnification of 10,000 times of a pure
titanium-based titanium alloy piece that had been etched with an
ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried;
[0062] FIG. 4 is a photograph as a result of observation with an
electron microscope in magnification of 100,000 times of a pure
titanium-based titanium alloy piece that had been etched with an
ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried;
[0063] FIG. 5 is a photograph as a result of observation with an
electron microscope in magnification of 10,000 times of an
.alpha.-.beta. type titanium alloy piece that had been etched with
an ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried; and
[0064] FIG. 6 is a photograph as a result of observation with an
electron microscope in magnification of 100,000 times of an
.alpha.-.beta. type titanium alloy piece that had been etched with
an ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0065] The various elements that make up the present invention will
now be described in detail.
[Titanium Alloy]
[0066] The substrate used in the present invention refers to the
product of machining a titanium alloy into a specific shape.
Titanium alloys include pure titanium of the type 1 to type 4 set
forth in the Japan Industrial Standard (JIS), .alpha. type alloys,
.beta. type alloys, .alpha.-.beta. type alloys and so forth and all
of these can serve as the substrate in the present invention. In
the present invention, the term "titanium alloy" encompasses what
is known as "pure titanium," as well as all of its alloys. For
example, pure titanium of type 1 and type 2 as set forth in the
Japan Industrial Standards (JIS) contain iron by 0.05 to 0.1% and
these are also called pure titanium-based titanium alloys.
[0067] [Surface Treatment of Titanium Alloy]
[0068] The surface of the titanium alloy substrate in the present
invention is covered with a thin film that is thicker than a
natural oxidized film. Chemical etching is needed to form this
cover film, while it is even better to cover the surface with a
ceramic. Titanium oxide is a specific example preferable for this
ceramic. The treatment to which the alloys are subjected usually
consists of three steps, namely, "a. degreasing", "b. chemical
etching", and "c. surface hardening" so as to be in line with the
hypothesis of the inventors proposed in relation to injection
joining, where for a titanium alloy, just two steps may be used,
namely, "a. degreasing" and "b. chemical etching". These steps will
hereinafter be referred to as surface treatment concerning with the
present invention.
[0069] Working oil used in machining, fingerprints and so forth
generally adhere to a titanium alloy part that has undergone
machining or the like, so the above-mentioned "a. degreasing step"
is performed as a treatment step of immersing the part in an
aqueous solution that contains a surfactant and then rinsing with
water to remove such oil. An aqueous solution in which a
neutralizer is dissolved can be used and it is preferable to use a
commercially available degreaser for iron, steel or aluminum
alloys. If a degreaser for titanium is commercially available, the
inventors believe that these commercially available degreasers can
also be used. The inventors just used an aluminum alloy degreaser
(which usually contain a surfactant and a small amount of a basic
agent), the details of which will be given in the working examples.
Specifically, a commercially available aluminum alloy degreaser was
adjusted to the concentration and temperature indicated by the
manufacturer (such as a concentration of about 7.5% and a solution
temperature of about 60.degree. C.), the titanium alloy part was
immersed for 5 to 10 minutes and then was rinsed with water.
Shortly speaking, the degreaser used in this degreasing step does
not need to be a special kind but any commercially available,
ordinary degreaser may be used.
[0070] In the next, "b. chemical etching" is performed. A titanium
alloy can be corroded by a reductive acid and, if the suitable type
of acid is chosen, the entire surface can be corroded.
Specifically, it is known that the entire surface can be corroded
by a high concentration of a halogen acid, sulfuric acid or a
high-temperature phosphoric acid aqueous solution. It has also been
reported in the catalog of a titanium manufacturer that entire
surface corrosion is achieved with an aqueous solution of oxalic
acid, which is an organic substance. An aqueous solution that can
bring about such entire surface corrosion can be used as chemical
etchant. However, there are many different types of titanium alloy
as mentioned above, so the results were confirmed by actual trial
and error. The easiest way was to use a hydrofluoric acid compound
as an acid that can bring about entire surface corrosion even in
the form of an aqueous solution that has been greatly diluted and
is close to room temperature. However, if hydrofluoric acid should
happen to touch the skin, it can penetrate and reach the bone,
where it will cause intense pain, and is therefore dangerous and
difficult to handle. In view of this, it is preferable to use
ammonium monohydrodifluoride, which has an adequate etching effect
while still being fairly safe to the human body. More specifically,
it is preferable to use an aqueous solution of ammonium
monohydrodifluoride with a concentration of a few percent and a
temperature of 50 to 70.degree. C.
[0071] With the pure titanium alloys of type 1 and type 2 set forth
in the Japan Industrial Standards (JIS), favorable chemical etching
was achieved by immersing for a few minutes in the above-mentioned
aqueous solution and then rinsing with water. The reaction here is
the oxidation of the titanium metal into titanium oxide, with the
water being reduced to generate hydrogen. The etching seems to have
occurred in the course of the production of this titanium oxide.
Assuming that the ammonium monohydrodifluoride is working mainly
catalytically as mentioned above, then it is anticipated that the
etching will begin at the metal crystal interface of the titanium,
so the etching method has to be designed according to the size of
the metal crystal grain size. When a commercially available
titanium alloy is procured, it will be easier to finely adjust the
etching process if the metal crystal grain size is known
beforehand.
[0072] This chemical etching is usually followed by the "c. surface
hardening treatment", where there may be cases in which bumps on
the nanometer (nm) order are produced simultaneously on the very
faces of the bumps on the micrometer (.mu.m) order. An ultrafine
textured face just happened to be produced on the titanium alloy
surface that had been chemically etched with the above-mentioned
hydrogen fluoride-based chemical. In such a case, the surface with
ultrafine texture formed does not actually have to undergo the "c.
surface hardening treatment", so long as the surface is formed with
a hard, stable metal oxide layer.
[0073] The titanium alloy surface was dark brown in color after
having been chemically etched with the ammonium monohydrodifluoride
aqueous solution, rinsed with water and dried, where XPS analysis
indicated that it was a titanium oxide surface. After degreasing,
the titanium alloy had the same metallic gloss as before degreasing
and the titanium alloy had obviously changed color after this
chemical etching. This reveals that the resulting surface is not a
natural oxidized film but rather a new titanium oxide. Oxide of
titanium(IV) is colorless or white, while oxide of titanium(III) is
dark purple, so this product seems to have been either a titanium
oxide consisting of a mixture of trivalent and tetravalent titanium
oxides or an alloy covered with thin layer mostly consisting of
trivalent titanium oxide. FIGS. 3 and 4 are electron micrographs of
the above-mentioned products obtained by degreasing and chemically
etching a titanium alloy of type 1 (pure titanium) as set forth in
the Japan Industrial Standards (JIS). Micron-order bumps can be
seen in FIG. 3, while nanometer-order bumps, that is, a coarse
texture, can be seen in FIG. 4.
[0074] Also, a titanium alloy of .alpha.-.beta. type was chemically
etched in a variety of ways and as a result the surface
configuration as viewed with an electron microscope was greatly
different from the ultrafine textured face expected from the
general theory proposed by the inventors. FIGS. 5 and 6 show
electron micrographs in magnification of 10,000 times and 100,000
times respectively and, as can be seen in micrograph in
magnification of 10,000 times, this is a strange surface in which
"both smooth dome-like shapes and dead leaf-like shapes are
observed" (in observation of a square that measures 10 .mu.m on
each side). When the surface was viewed in a low magnification,
these two types of surfaces (domes and dead leaves) coexisted in a
sufficiently blended state. When it comes to injection joining, it
seems that dome-like surfaces probably do not play a part while the
dead leaf-like surfaces afford somewhat better grip and serve as
effective spikes. For roughness measured by scanning probe
microscope, the range in which excellent joint strength was
exhibited in injection joining shifted towards somewhat larger side
for the maximum height of roughness (Rz). Here, RSm was in the same
range of 1 to 10 .mu.m and Rz was 0.5 to 10 .mu.m as one-half of
RSm, where preferably Rz would be 1 to 5 .mu.m.
[0075] The importance of using chemical etching will be described
here. Any method can be used as long as the anticipated surface
configuration discussed above is obtained but the question occurs
as to why chemical etching is required. This is related to the
situation where it is believed that the designed fine textured face
can be achieved with one of the recent sophisticated ultrafine
working methods in which the material is coated with a
photochemical resist and visible light rays or ultraviolet rays are
used. However, there are some reasons why chemical etching is
particularly favorable for injection joining other than simplicity
of operation entailed. Specifically, if the chemical etching is
carried out under the right conditions, not only will the
appropriate bump period and the appropriate recess depth be
obtained but the fine shape of the resulting recesses will not be
simple and most of the recesses will have an undercut structure. An
undercut structure means that there are places that cannot be seen
inside the recesses when the recesses are viewed from above and, if
we could look at these microscopically from the bottom of the
recess, overhanging places would be seen. It should be easily
understood that undercut structures are necessary for injection
joining.
[0076] [Resin Composition]
[0077] The resin composition used in the present invention refers
to a first resin composition whose main component is a
polyphenylene sulfide resin or a second resin composition whose
main component is a polybutylene terephthalate resin, both of the
resin composition being crystalline resins and directly joined to
the above-mentioned titanium alloy substrate. The resin component
of this first resin composition is a resin composition in which a
polyphenylene sulfide resin is the main component and a polyolefin
resin is an auxiliary component. The resin component of the second
resin composition is a resin composition in which the polybutylene
terephthalate resin is the main component and a polyethylene
terephthalate resin and/or a polyolefin resin is an auxiliary
component.
[0078] The first resin composition preferably contain the
above-mentioned polyphenylene sulfide resin by 70 to 97 wt % and
the above-mentioned polyolefin resin by 3 to 30 wt %. The second
resin composition preferably contain the above-mentioned
polybutylene terephthalate resin by 70 to 97 wt % and the
above-mentioned polyethylene terephthalate resin and/or polyolefin
resin by 3 to 30 wt %. If different types of resin are thus mixed
at the molecular level, it is surmised that even when the
crystallization temperature is reached, the same types will not
join together abruptly and generation of microcrystallization or
growth of crystals will be delayed by a very short time.
[0079] A high-hardness, crystalline resin composition that is used
as the resin composition is preferably PPS or PBT containing at
least one type of filler selected from among glass fiber, carbon
fiber, aramid fiber, other such reinforcing fiber, calcium
carbonate, magnesium carbonate, silica, talc, clay and glass
powder, in an amount of 20 to 60 wt % of the total composition.
This is because adding these fillers allows the linear coefficient
of expansion of the molded resin to be adjusted to 2 to
3.times.10.sup.5.degree. C.' and kept as low as possible.
[0080] [Resin Composition/PPS]
[0081] The PPS resin composition will now be discussed. When the
resin component is composed of PPS by 70 to 97% and polyolefin
resin by 3 to 30%, a composite with particularly good joint
strength can be obtained. If the polyolefin resin content is less
than 3%, the effect of adding the polyolefin resin on enhancing
injection joining strength will not be reliable. Meanwhile, the
same applies when the polyolefin resin content is more than 30%.
With a PPS resin to which more than 30% polyolefin resin has been
added, the pyrolysis of the polyolefin resin in the injection
barrel of the injection molding machine will result in an
abnormally large amount of gas being generated, which can hinder
even the injection molding itself.
[0082] Any PPS can be used as long as it is classified as PPS,
while one with a melt viscosity of 100 to 30,000 poise as measured
at a temperature of 315.degree. C. and a load of 98 N (10 kgf) with
a Koka type flow tester mounted with a die 1 mm in diameter and 2
mm long is preferable because it will have better moldability and
workability when formed into a resin composition part. Also, the
PPS may be one substituted with amino groups, carboxyl groups or
the like or may be one copolymerized with trichlorobenzene or the
like during polymerization.
[0083] Also, the PPS may be of a linear structure or may have some
branched structure within it and may have undergone heat treatment
in an inert gas, etc. Furthermore, the ions, oligomers or other
such impurities in the PPS may have been reduced by performing a
deionization treatment (acid washing, hot water washing, etc.) or
washing treatment with an organic solvent such as acetone before or
after heating and curing, while its curing may have been promoted
by performing a heat treatment in an oxidative gas upon completion
of the polymerization reaction.
[0084] The polyolefin resin is an ethylene resin, propylene resin
or other such material normally known as a polyolefin resin and may
be a commercially available product. Of these, maleic
anhydride-modified ethylene copolymers, glycidyl
methacrylate-modified ethylene copolymers, glycidyl ether-modified
ethylene copolymers, ethylene alkyl acrylate copolymers or the like
are preferable because a composite with particularly excellent
bondability can be obtained.
[0085] Examples of maleic anhydride-modified ethylene copolymers
include maleic anhydride graft-modified ethylene copolymers, maleic
anhydride-ethylene copolymers and ethylene-acrylic acid
ester-maleic anhydride ternary copolymers, of which an
ethylene-acrylic acid ester-maleic anhydride ternary copolymer is
preferable because a particularly excellent composite is obtained.
A specific example of an ethylene-acrylic acid ester-maleic
anhydride ternary copolymer is Bondine (made by Arkema).
[0086] Examples of glycidyl methacrylate-modified ethylene
copolymers include glycidyl methacrylate graft-modified ethylene
copolymers and glycidyl methacrylate-ethylene copolymers, of which
a glycidyl methacrylate-ethylene copolymer is preferable because a
particularly excellent composite is obtained. A specific example of
a glycidyl methacrylate-ethylene copolymer is Bondfast (made by
Sumitomo Chemical). Examples of glycidyl ether-modified ethylene
copolymers include glycidyl ether graft-modified ethylene
copolymers and glycidyl ether-ethylene copolymers and a specific
example of an ethylene alkyl acrylate copolymer is Lotryl (made by
Arkema).
[0087] With the composite in the present invention, the resin
composition part preferably contains polyfunctional isocyanate
compound by 0.1 to 6 weight parts and/or epoxy resin by 1 to 25
parts per 100 weight parts of the total resin component including
PPS by 70 to 97 wt % and polyolefin resin by 3 to 30 wt %, because
the joining of the shaped titanium alloy and the resin composition
part will be better. A commercially available non-blocked or
blocked polyfunctional isocyanate compound can be used.
[0088] Examples of polyfunctional non-blocked isocyanate compounds
include 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylpropane
diisocyanate, toluene diisocyanate, phenylene diisocyanate and
bis(4-isocyanate phenyl)sulfone. A polyfunctional blocked
isocyanate compound has two or more isocyanate groups per molecule,
where these isocyanate groups reacted with a volatile active
hydrogen compound, making the material inert at normal temperature.
There are no particular restrictions on the type of polyfunctional
blocked isocyanate compound but generally it will have a structure
in which the isocyanate groups are masked by a blocking agent such
as an alcohol, a phenol, .epsilon.-caprolactam, an oxime or an
active methylene compound.
[0089] An example of a polyfunctional blocked isocyanate is
Takenate (made by Mitsui Takeda Chemical). The epoxy resin can be
any commonly known type such as a bisphenol A type or a cresol
novolac type. An example of a bisphenol A type is Epikote (made by
Japan Epoxy Resin), while an example of a cresol novolac type is
Epiclon (made by Dainippon Ink & Chemicals).
[0090] [Resin Composition/PBT]
[0091] The PBT resin composition will now be discussed. Preferably,
the resin composition will include not just the above-mentioned
filler but also PET and/or polyolefin resin by 3 to 30 wt % and PBT
by 70 to 97 wt %. Injection joining strength is superior with a PBT
resin composition in which PBT is the main component and PET and/or
a polyolefin resin is an auxiliary component. The same polyolefin
resins as those listed for the PPS resin composition can be used.
Joint strength will be highest when the PET and/or polyolefin resin
accounts for 5 to 20 wt %, while the joint strength will still not
be significantly lowered at 3 to 5 wt % or at 20 to 30 wt %.
However, if the amount is more than 30 wt %, the effect on
injection joining strength will be diminished and, if the PET
component is over 25 wt %, an ester interchange reaction with PBT
will be more likely to proceed at the high temperatures in the
injection molding machine, so there is the risk that the strength
of the resin itself will be lowered. Also, if the polyolefin resin
component is over 30 wt %, more gas will be generated and
moldability will tend to be worsened.
[0092] [Manufacturing of Composite/Injection Joining]
[0093] The method for manufacturing a composite according to the
present invention is an injection joining method in which a metal
part is inserted and is performed as follows. A metallic mold for
injection molding is made ready, the mold is opened, a shaped
titanium alloy obtained by the above-mentioned treatment is
inserted into one half of the mold, the mold is closed and a PPS-
or PBT-based thermoplastic resin composition is injected and
solidified, after which the mold is opened and the product removed,
thus a composite being manufactured. The injection conditions will
now be described. The mold temperature is preferably at least
100.degree. C., more preferably at least 120.degree. C., for a PBT
resin or PPS resin, because there will be little effect on resin
strength after solidification and composite production efficiency
will be made better. The injection temperature, injection pressure
and injection rate are not much different from those of ordinary
injection molding but, if pressed to say, the injection rate and
injection pressure are better on the high side.
[0094] Embodiments of the present invention will now be described
through working examples.
[0095] FIGS. 1 and 2 are to be referred to in common for various
working examples, where FIG. 1 is a cross sectional view
schematically illustrating a metallic mold for injection molding 10
used in the working examples. The figure shows a state in which the
metallic mold for injection molding 10 has been closed and
injection molding is being performed. FIG. 2 is an exterior view
schematically illustrating a composite 7 of a metal and a resin
formed in the metallic mold for injection molding 10. This mold for
injection molding 10 is made up of a movable mold plate 2 and a
stationary mold plate 3 and a resin injector comprising a pinpoint
gate 5, a runner, and so forth is constituted on the stationary
mold plate 3 side.
[0096] The formation of the composite 7 is carried out as follows.
First, the movable mold plate 2 is opened and a titanium alloy
piece 1 which is a substrate composed of a titanium alloy is
inserted into the cavity formed between the movable mold plate 2
and the stationary mold plate 3. After this insertion, the movable
mold plate 2 is closed, resulting in the state before injection. A
molten resin composition 4 is then injected through the pinpoint
gate 5 into the cavity in which the titanium alloy piece 1 was
inserted.
[0097] After being injected, the resin composition 4 is mated to
the titanium alloy piece 1, fills the cavity that is not occupied
by the titanium alloy piece 1 and is molded, thereby a composite 7,
in which the titanium alloy piece 1 and the resin composition 4
(metal and resin) are integrated, is obtained. The composite 7 has
a joining face 6 between the titanium alloy piece 1 and the resin
composition 4 and the surface area of this joining face 6 is 5
mm.times.10 mm. Specifically, the surface area of the joining face
6 is 0.5 cm.sup.2. In the following working examples, strength test
is conducted using the same surface area of the joining face.
Strength is obtained under the same conditions in the comparative
examples given below, as well.
[0098] Working examples of the present invention will now be
described in detail.
[0099] First, the methods for evaluating and measuring the
composites obtained in the following working examples will be
described.
(a) Measurement of Melt Viscosity
[0100] The melt viscosity of thermoplastic resin was measured with
a Koka-type flow tester (CFT-500, made by Shimadzu, Kyoto, Japan)
equipped with die having a diameter of 1 mm and a length of 2 mm,
at a measurement temperature of 315.degree. C. and a load of 98 N
(10 kgf).
(b) X-ray Photoelectron Analyzer (XPS Observation)
[0101] Surface observation method involved the use of photoelectron
analyzer (XPS observation) that analyzes the energy of
photoelectrons emitted from the sample upon irradiation of the same
with X-rays and performs qualitative analysis of elements or the
like. This photoelectron analyzer was an Axis-Nova (product name;
made by Kratos Analytical: England and Shimadzu: Japan), which is a
model that allows a surface only a few microns in diameter to be
observed to a depth of a few nanometers.
[0102] (c) Electron Beam Microanalyzer (EPMA Observation)
[0103] EPMA was mainly used to observe the interior of the
substrate. Elements contained down to a depth of about 1 .mu.m from
the surface could be detected. Observation was conducted at 15 kV
with an EPMA-1600 (trade name; made by Shimadzu).
[0104] (d) Electron Microscopy
[0105] Electron microscopes were mainly used to observe the
substrate surface. These electron microscopes were a scanning
electron microscope (SEM) 5-4800 (product name; made by Hitachi,
Tokyo, Japan) and JSM-6700F (product name; made by JEOL, Tokyo,
Japan), where observations were made at 1 to 2 kV. The
magnification was 10,000 times and 100,000 times, and photographs
were taken with scales of 1 .mu.m and 100 nm recorded within.
[0106] (e) Scanning Probe Microscopy
[0107] A scanning probe microscope was used mainly to observe
substrate surfaces. This microscope is a scanning probe microscope
in which a probe with a pointed tip is used so that it may be moved
scanning the surface of substance and the surface condition is
enlarged for observation. This scanning probe microscope was an
SPM-9600 (product name; made by Shimadzu, Kyoto, Japan).
[0108] (f) Measurement of Composite Joining Strength
[0109] Tensile stress was measured by pulling the composite 7 in a
tensile tester to impart shearing force and the breaking force at
break was termed the shear stress. This tensile tester was a Model
1323 (product name; made by Aikoh Engineering, Tokyo, Japan) and
the shearing force was measured at a pulling rate of 10
mm/minute.
[0110] In the next, the preparation examples of resin compositions
will be described.
Preparation Example 1
PPS Composition Preparation Example
[0111] 6214 g of Na.sub.2S.2.9H.sub.2O and 17,000 g of
N-methyl-2-pyrrolidone were supplied to a 50 liter autoclave
equipped with a stirrer. The temperature was gradually raised to
205.degree. C. while stirring the system under a nitrogen gas flow
and 1355 g of water was distilled off. This system was cooled to
140.degree. C., after which 7160 g of p-dichlorobenzene and 5000 g
of N-methyl-2-pyrrolidone were added and the system was sealed
under a nitrogen gas flow. The temperature of the system was raised
to 225.degree. C. over 2 hours, the system was polymerized for 2
hours at 225.degree. C., then the temperature was raised to
250.degree. C. over 30 minutes and polymerization was conducted for
another 3 hours at 250.degree. C. Upon completion of the
polymerization, the system was cooled to room temperature and the
polymer was separated in a centrifuge. The solids of the polymer
were repeatedly washed with warm water and dried over night at
100.degree. C., which gave PPS with a melt viscosity of 280 poise
(hereinafter referred to as PPS (1)).
[0112] This PPS (1) was cured for 3 hours at 250.degree. C. under a
nitrogen atmosphere to obtain PPS (hereinafter referred to as PPS
(2)). The melt viscosity of the resulting PPS (2) was 400 poise.
6.0 kg of the resulting PPS (2), 1.5 kg of ethylene-acrylic
ester-maleic anhydride ternary copolymer (Bondine TX8030, made by
Arkema) and 0.5 kg of epoxy resin (Epicote 1004, made by Japan
Epoxy Resin) were uniformly mixed preliminarily in a tumbler. After
this, glass fiber with an average fiber diameter of 9 .mu.m and a
fiber length of 3 mm (RES03-TP91, made by Nippon Sheet Glass) was
supplied by side feeder so that the added amount would be 20 wt %
while being melt-kneaded in a biaxial extruder (TEM-35B, made by
Toshiba Machine) at a cylinder temperature of 300.degree. C., which
gave a pelletized PPS composition (1). The resulting PPS
composition (1) was dried for 5 hours at 175.degree. C.
Preparation Example 2
Preparation of PPS Composition
[0113] The PPS (1) obtained in Preparation Example 1 was cured for
3 hours at 250.degree. C. under an oxygen atmosphere, which gave
PPS (hereinafter referred to as PPS (3)). The resulting PPS (3) had
a melt viscosity of 1800 poise. 5.98 kg of the resulting PPS (3)
and 0.02 kg of polyethylene (Nipolon Hard 8300A, made by Tosoh)
were uniformly mixed preliminarily in a tumbler. After this, glass
fiber with an average fiber diameter of 9 .mu.m and a fiber length
of 3 mm (RES03-TP91) was supplied by side feeder so that the added
amount would be 40 wt % while these were melt-kneaded in a biaxial
extruder (TEM-35B) at a cylinder temperature of 300.degree. C.,
which gave a pelletized PPS composition (2). The resulting PPS
composition (2) was dried for 5 hours at 175.degree. C.
Preparation Example 3
Preparation of PPS Composition
[0114] 7.2 kg of the PPS (2) obtained in Preparation Example 1 and
0.8 kg of glycidyl methacrylate-ethylene copolymer (Bondfast E,
made by Sumitomo Chemical) were uniformly mixed preliminarily in a
tumbler. After this, glass fiber with an average fiber diameter of
9 .mu.m and a fiber length of 3 mm (RES03-TP91) was supplied by
side feeder so that the added amount would be 20 wt % while these
were melt-kneaded in a biaxial extruder (TEM-35B) at a cylinder
temperature of 300.degree. C., which gave a pelletized PPS
composition (3). The resulting PPS composition (3) was dried for 5
hours at 175.degree. C.
Preparation Example 4
Preparation of PPS Composition
[0115] 4.0 kg of the PPS (2) obtained in Preparation Example 1 and
4.0 kg of ethylene-acrylic ester-maleic anhydride ternary copolymer
(Bondine TX8030, made by Arkema) were uniformly mixed preliminarily
in a tumbler. After this, glass fiber with an average fiber
diameter of 9 .mu.m and a fiber length of 3 mm (RES03-TP91) was
supplied by side feeder so that the added amount would be of 20 wt
% while these were melt-kneaded in a biaxial extruder (TEM-35B) at
a cylinder temperature of 300.degree. C., which gave a pelletized
PPS composition (4). The resulting PPS composition (4) was dried
for 5 hours at 175.degree. C.
Preparation Example 5
Preparation of PBT Composition
[0116] 4.5 kg of PBT resin (Toraycon 1100S, made by Toray) and 0.5
kg of PET resin (TR-4550BH, made by Teijin Kasei) were uniformly
mixed in a tumbler. After this, glass fiber with an average fiber
diameter of 9 .mu.m and a fiber length of 3 mm (RES03-TP91) was
supplied by side feeder so that the added amount would be 30 wt %
while these were melt-kneaded in a biaxial extruder (TEM-35B) at a
cylinder temperature of 270.degree. C., which gave a pelletized PBT
resin composition. This was dried for 3 hours at 140.degree. C. to
obtain a PBT composition (1).
Preparation Example 6
Preparation of PBT Composition
[0117] 6.0 kg of PBT resin (Toraycon 1401X31, made by Toray), 0.7
kg of ethylene-acrylic ester-maleic anhydride ternary copolymer
(Bondine TX8030, made by Arkema) and 0.15 kg of epoxy resin
(Epicote 1004, made by Japan Epoxy Resin) were uniformly mixed
preliminarily in a tumbler. After this, glass fiber with an average
fiber diameter of 9 .mu.m and a fiber length of 3 mm (RES03-TP91,
made by Nippon Sheet Glass) was supplied by side feeder so that the
added amount would be 30 wt % while being melt-kneaded in a biaxial
extruder (TEM-35B, made by Toshiba Machine) at a cylinder
temperature of 270.degree. C., which gave a pelletized PBT
composition (2). The resulting PBT composition (2) was dried for 5
hours at 150.degree. C.
Preparation Example 7
Preparation of PBT Composition
[0118] 6.0 kg of PBT resin (Toraycon 1401X31, made by Toray), 0.5
kg of PET resin (TR-4550BH, made by Teijin Kasei), 0.5 kg of
ethylene-acrylic ester-maleic anhydride ternary copolymer (Bondine
TX8030, made by Arkema) and 0.1 kg of epoxy resin (Epicote 1004,
made by Japan Epoxy Resin) were uniformly mixed preliminarily in a
tumbler. After this, glass fiber with an average fiber diameter of
9 .mu.m and a fiber length of 3 mm (RES03-TP91, made by Nippon
Sheet Glass) was supplied by side feeder so that the added amount
would be 30 wt % while these were melt-kneaded in a biaxial
extruder (TEM-35B, made by Toshiba Machine) at a cylinder
temperature of 270.degree. C., which gave a pelletized PBT
composition (3). The resulting PBT composition (3) was dried for 5
hours at 150.degree. C.
[0119] Working and comparative examples of composites will now be
further described.
Working Example 1
[0120] Commercially available KS-40 (made by Kobe Steel) sheeting,
which is a pure titanium-based type 1 titanium alloy under the
Japan Industrial Standards (JIS) and which has a thickness of 1.0
mm, was purchased and cut into numerous rectangular pieces
measuring 18 mm.times.45 mm to obtain titanium alloy pieces
(titanium alloy substrates). A hole was formed to pass through the
end of each titanium alloy piece, a copper wire coated with
polyvinyl chloride was passed through the holes of a dozen or so
pieces and the copper wire was bent so that the titanium alloy
pieces would not overlap each other, thus allowing all pieces to be
hung up at the same time. An aqueous solution containing aluminum
alloy degreaser (NE-6, made by Meltex) by 7.5% was adjusted to
60.degree. C. and made ready in a tank, the above-mentioned
titanium alloy pieces were immersed for 5 minutes and rinsed with
tap water (Ota City, Gunma, Japan).
[0121] In the next, an aqueous solution containing ammonium
monohydrodifluoride by 1% and adjusted to 60.degree. C. was made
ready in another tank, the above-mentioned titanium alloy pieces
were immersed for 2 minutes and then thoroughly rinsed with
deionized water. They were then dried for 15 minutes in a warm air
dryer set to 90.degree. C. The surface was dark brown in color. The
copper wire was taken out of the titanium alloy pieces placed on a
clean aluminum foil, the pieces were wrapped up together, then put
in a plastic bag, sealed and stored. In this work, no fingers
touched the surfaces to be joined, that is, the end portions on the
opposite side from where each hole was formed, to preserve the
above-mentioned treated state.
[0122] Two days later, one of the pieces was cut and observed with
an optical microscope, an electron microscope and a scanning probe
microscope. The results of observation with the electron microscope
are shown in FIGS. 3 and 4. The surface has a strange configuration
of superfine texture in which bent, ridge-like protrusions having a
width and height of 10 to 300 nm and a length of from 100 to a few
thousand nanometers rise up on the surface at a spacing period of
10 to 300 nm. Meanwhile, in observation with a scanning probe
microscope, a surface roughness was observed in which the mean
value of RSm was 2 to 3 .mu.m at a period of 0.5 to 5 .mu.m and the
maximum depth was about 3 .mu.m. In observation with XPS, large
amounts of oxygen, titanium and carbon were seen, while small
amounts of nitrogen, calcium and the like were also noted. No
metallic titanium was noted in the titanium but a tiny amount of
titanium carbide was detected. A face that had been shaved
(thinned) by approximately 100 nm by etching with argon ions was
analyzed again with XPS and here again titanium, oxygen and carbon
were detected in large amounts, while, for titanium atoms,
considerable metallic titanium, titanium carbide and titanium
nitride were detected, which revealed that the metal phase was also
detected.
[0123] To put this in another way, the thickness of the titanium
oxide layer was 50 to 100 nm, which was substantially thick. Also,
the deeper going into the layer, the more the titanium ions
(divalent to tetravalent) tend to decrease, so the surface layer
contains more titanium dioxide, while dititanium trioxide and
titanium monoxide as well as titanium nitride and titanium carbide
that are close to Ti (zero valence) increase towards deeper layer,
leading to the conclusion that this would eventually become a
metallic titanium phase. Incidentally, when the KS-40 titanium
alloy was analyzed by XPS immediately after purchase, this data was
the same as the surface analysis result for the etched product.
However, when this titanium alloy was shaved down by 100 nm with
argon ions and the shaved surface was analyzed with XPS, a large
amount of metallic titanium was detected. These results revealed
that the titanium oxide layer on the titanium alloy surface is
clearly thicker on the pieces etched, rinsed and dried by the
inventors than on the pieces machined as sheeting.
[0124] Also, the above-mentioned XPS analysis results indicate that
this might be a titanium dioxide (tetravalent Ti) single layer but,
even if it is a titanium dioxide layer, it is extremely thin and is
considered to be an oxide of mixed trivalent and tetravalent
titaniums. This is because the titanium alloy after etching lost
its metallic color and turned dark brown, while the dititanium
trioxide, which is an oxide of trivalent titanium, was dark purple
in color. Also, the ridge-like bumps seen in the electron
micrograph of FIG. 4 may be mainly of titanium dioxide, and the
foundation may be a mixed oxide layer. It is possible that the
question could be answered by performing Auger electron analysis,
which allows analysis of a narrow region measuring just a few
nanometers but the inventors did not perform this.
[0125] Further one day later, the remaining titanium alloy pieces 1
were taken out. For each of the pieces, the portion with the hole
formed was grasped with a glove so that no oil or the like might
adhere and each piece was inserted into a metallic mold for
injection molding 10. The metallic mold for injection molding 10
was closed and the PPS composition (1) obtained in Preparation
Example 1 was injected at an injection temperature of 310.degree.
C. The mold temperature of the metallic mold for injection molding
10 was 140.degree. C. and 20 of the integrated composites 7 shown
in FIG. 2 were obtained. The size of the resin part was 10
mm.times.45 mm.times.5 mm and the joining face 6 measured 10
mm.times.5 mm (0.5 cm.sup.2). The composites 7 were placed for 1
hour in a hot air dryer at the temperature of 170.degree. C. on the
day of molding to anneal them and then one day later they were
subjected to tensile test, which revealed the average shear
breaking strength to be 25 MPa.
Working Example 2
[0126] Other than using the PPS composition (2) obtained in
Preparation Example 2 instead of the PPS composition (1) obtained
in Preparation Example 1, titanium alloy pieces 1 were produced,
injection molding was performed and composites 7 were obtained
under exactly the same experimental conditions as in Working
Example 1. The composites 7 thus obtained were annealed for 1 hour
at 170.degree. C. In short, in this experiment a PPS resin
composition containing only PPS and a filler and containing only a
tiny amount of polyolefin polymer was used. After one day, ten of
the composites 7 were subjected to tensile test, which revealed the
average shear breaking strength to be 8 MPa. This was far from
Working Example 1 and the difference in the resin composition
material used appeared in the result.
Working Example 3
[0127] Other than using the PPS composition (3) obtained in
Preparation Example 3 instead of the PPS composition (1) obtained
in Preparation Example 1, composites 7 were obtained by exactly the
same method as in Working Example 1. The composites 7 were annealed
for 1 hour at 170.degree. C. on the day of molding. Two days later
these composites 7 were measured for shear breaking strength with a
tensile tester and the average was found to be 16.3 MPa.
Comparative Example 1
[0128] Other than using the PPS composition (4) obtained in
Preparation Example 4 instead of the PPS composition (1), an
attempt was made to obtain a composite by the same method as in
Working Example 1. In short, in this experiment a PPS resin
composition was used that contained a large amount of polyolefin
polymer. However, a large quantity of gas was generated during
molding and this caused the molding to be stopped. In this
experiment the main component of the resin composition was not
PPS.
Working Example 4
[0129] Other than using the PBT composition (1) obtained in
Preparation Example 5 instead of the PPS composition (1) obtained
in Preparation Example 1, titanium alloy pieces 1 were produced,
injection molding was performed and composites 7 were obtained by
exactly the same method as in Working Example 1. The injection
temperature was 280.degree. C., the mold temperature was
140.degree. C. and the annealing conditions for the obtained
composites 7 were 1 hour at 150.degree. C. One day later, these
composites 7 were subjected to tensile test, which revealed the
shear breaking strength to be an average of 21 MPa for 10
pieces.
Working Example 5
[0130] Other than using the PBT composition (2) obtained in
Preparation Example 6 instead of the PBT composition (1) obtained
in Working Example 5, titanium alloy pieces 1 were produced,
injection molding was performed and composites 7 were obtained by
exactly the same method as in Working Example 5. The annealing
conditions for the obtained composites 7 were also the same. One
day later, these composites 7 were subjected to tensile test, which
revealed the shear breaking strength to be an average of 19.6 MPa
for 10 pieces.
Working Example 6
[0131] Other than using the PBT composition (3) obtained in
Preparation Example 7 instead of the PBT composition (1) obtained
in Preparation Example 5, titanium alloy pieces 1 were produced,
injection molding was performed and composites 7 were obtained by
exactly the same method as in Working Example 5. The annealing
conditions for the obtained composites 7 were also the same. One
day later, these composites 7 were subjected to tensile test, which
revealed the shear breaking strength to be an average of 24.4 MPa
for 10 pieces.
Working Example 7
[0132] Commercially available KS-40 (made by Kobe Steel; pure
titanium-based type 1 titanium alloy of Japan Industrial Standards
(JIS)) sheeting with a thickness of 1.0 mm was cut into rectangular
pieces measuring 18.times.45 mm. A hole was formed to pass through
the end of each of the titanium alloy pieces, a copper wire coated
with polyvinyl chloride was passed through the holes of a dozen or
so pieces and the copper wire was bent so that the titanium alloy
pieces would not overlap each other, thus allowing all pieces to be
hung up at the same time. An aqueous solution containing aluminum
alloy degreaser (NE-6, made by Meltex) by 7.5% was adjusted to
60.degree. C. and made ready in a tank, the titanium alloy pieces
were immersed for 5 minutes and thoroughly rinsed with tap water
(Ota City, Gunma, Japan).
[0133] In the next, an aqueous solution in which a multipurpose
etchant containing ammonium monohydrodifluoride by 40% and adjusted
to 60.degree. C. (KA-3; made by the National Institute for
Metalworking Skills, Sumida-ku, Tokyo) had been dissolved in an
amount of 2 wt % was adjusted to 60.degree. C. and made ready in
another tank. The titanium alloy pieces were immersed in this for 3
minutes and then thoroughly rinsed with deionized water. They were
then dried for 15 minutes in a warm air dryer set to 90.degree. C.
The surface was dark brown in color. The copper wire was taken out
of the titanium alloy pieces placed on a clean aluminum foil, the
pieces were wrapped up together, then put in a plastic bag, sealed
and stored. In this work, no fingers touched the surfaces to be
joined, that is, the end portion on the opposite side from where
each hole was made.
[0134] Three days later the titanium alloy pieces 1 were taken out,
the portion with a hole was grasped with a glove so that no oil or
the like would adhere and each piece was inserted into a metallic
mold for injection molding 10. The injection molding mold 10 was
closed and the PPS composition (1) obtained in Preparation Example
1 was injected at an injection temperature of 310.degree. C. The
mold temperature was 140.degree. C. and 20 of the integrated
composites 7 shown in FIG. 2 were obtained. The size of the resin
part was 10 mm.times.45 mm.times.5 mm and the joining face 6
measured 10 mm.times.5 mm (0.5 cm.sup.2). The composites 7 were
placed for 1 hour in a hot air dryer at the temperature of
170.degree. C. on the day of molding to anneal them and then
further one day later they were subjected to tensile test, which
revealed the average shear breaking strength to be 26.5 MPa.
Working Example 8
[0135] Commercially available pure titanium-based type 2 titanium
alloy sheeting TP340 with a thickness of 1.0 mm under Japan
Industrial Standards (JIS) was purchased and cut into rectangular
pieces measuring 18 mm.times.45 mm to obtain titanium alloy pieces
as the titanium alloy substrates. After this, surface treatment was
performed in exactly the same manner as in Working Example 1.
Furthermore, the PPS composition (1) was used for injection joining
in exactly the same manner as in Working Example 1. 20 composites 7
were obtained and placed for 1 hour in a hot air dryer at the
temperature of 170.degree. C. on the day of molding to anneal them
and then one day later they were subjected to tensile test, which
revealed the average shear breaking strength to be 26 MPa.
Working Example 9
[0136] Commercially available sheeting of .alpha.-.beta.-type
titanium alloy KSTi-9 with a thickness of 1.0 mm (made by Kobe
Steel) was purchased and cut into numerous rectangular pieces
measuring 18 mm.times.45 mm to obtain titanium alloy pieces as
titanium alloy substrates. A hole was formed to pass through the
end of each of the titanium alloy pieces, copper wire coated with
polyvinyl chloride was passed through the holes of a dozen or so
pieces and the copper wire was bent so that the titanium alloy
pieces would not overlap each other, thus allowing all to be hung
up at the same time. An aqueous solution containing aluminum alloy
degreaser (NE-6, made by Meltex) by 7.5% was adjusted to 60.degree.
C. and made ready in a tank, the titanium alloy pieces were
immersed for 5 minutes and rinsed with tap water (Ota City, Gunma,
Japan).
[0137] In the next, an aqueous solution containing caustic soda by
1.5% and adjusted to 40.degree. C. was made ready in a separate
tank, the above-mentioned pieces were immersed for 1 minute and
then thoroughly rinsed with water. Then, an aqueous solution
containing a commercially available etchant KA-3 (made by the
National Institute for Metalworking Skills; labeled as containing
ammonium monohydrodifluoride by 40% and other by 60%) by 2% was
adjusted to 60.degree. C. and made ready in another tank, the
above-mentioned titanium alloy pieces were immersed in this for 5
minutes and then thoroughly rinsed with deionized water. Then, an
aqueous solution containing oxalic acid by 5% was adjusted to
40.degree. C. and made ready in another tank, the above-mentioned
alloy pieces were immersed for 15 seconds, then thoroughly rinsed
with deionized water and then they were dried for 15 minutes in a
warm air dryer set to 90.degree. C. The copper wire was taken out
of the titanium alloy pieces placed on a clean aluminum foil, the
pieces were wrapped up together, then put in a plastic bag, sealed
and stored. In this work, no fingers touched the surfaces to be
joined, that is, the end portion on the opposite side from where
each hole was made).
[0138] Two days later, one of the pieces was cut and observed with
an optical microscope, an electron microscope and a scanning probe
microscope. The results of observation with the electron microscope
are shown in the micrographs of FIGS. 5 and 6. The surface
configuration was not a uniform pattern and, as can be seen in the
micrograph of FIG. 5 in magnification of 10,000 times, the surface
was a mixture of dome-like shapes and dead leaf-like shapes. The
basic structure was probably a mixture of different types of metal
crystals and it is surmised that different surfaces were formed
when these were etched. The micrograph of FIG. 6 in magnification
of 100,000 times is an enlargement of just one of these but there
are few bumps with a nanometer period, be it dome-like portions or
dead leaf-like portions, or to put this in another way the surface
had the feel of a slick ceramic and was not the ultrafine surface
that would be expected for injection joining or adhesive
joining.
[0139] However, the dead leaf-like portions were three-dimensional
and seemed to serve as spikes. In other words, the configuration of
the alloy surface after the treatment was different from the
ultrafine textured shape that was anticipated by the inventors
under their general theory, with the overall period on the larger
side but with the shape being three-dimensional enough to cancel it
out. This will be discussed below but seems to be the reason that a
certain injection joining strength was obtained. In observation
with a scanning probe microscope, roughness in which RSm was 1.5 to
2.5 .mu.m and Rz was 1.2 to 2.1 .mu.m was observed through four
scans of 20 .mu.m, the Rz value was large in relation to the value
of RSm and here again there was an overall three-dimensional
appearance.
[0140] Further one day later, the remaining titanium alloy pieces 1
were taken out, the portion with the hole was grasped with a glove
so that no oil or the like would adhere and each piece was inserted
into a metallic mold for injection molding 10. The metallic mold
for injection molding 10 was closed and the PPS composition (1)
obtained in Preparation Example 1 was injected at an injection
temperature of 310.degree. C. The mold temperature was 140.degree.
C. and 20 of the integrated composites 7 shown in FIG. 2 were
obtained. The size of the resin part was 10 mm.times.45 mm.times.5
mm and the joining face 6 measured 10 mm.times.5 mm (0.5 cm.sup.2).
The composites 7 were placed for 1 hour in a hot air dryer at the
temperature of 170.degree. C. on the day of molding to anneal them
and then one day later they were subjected to tensile test, which
revealed the average shear breaking strength to be 25 MPa.
BRIEF DESCRIPTION OF THE DRAWINGS
[0141] FIG. 1 is a cross sectional view schematically illustrating
a metallic mold for manufacturing a composite of metal and resin (a
titanium alloy substrate and a resin composition);
[0142] FIG. 2 is an exterior view schematically illustrating a
composite of metal and resin (a titanium alloy substrate and a
resin composition);
[0143] FIG. 3 is a photograph as a result of observation with an
electron microscope in magnification of 10,000 times of a pure
titanium-based titanium alloy piece that had been etched with an
ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried;
[0144] FIG. 4 is a photograph as a result of observation with an
electron microscope in magnification of 100,000 times of a pure
titanium-based titanium alloy piece that had been etched with an
ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried;
[0145] FIG. 5 is a photograph as a result of observation with an
electron microscope in magnification of 10,000 times of an
.alpha.-.beta. type titanium alloy piece that had been etched with
an ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried; and
[0146] FIG. 6 is a photograph as a result of observation with an
electron microscope in magnification of 100,000 times of an
.alpha.-.beta. type titanium alloy piece that had been etched with
an ammonium monohydrodifluoride aqueous solution, rinsed with water
and dried.
DESCRIPTION OF THE REFERENCE NUMBERS
[0147] 1 Substrate of titanium alloy [0148] 2 Movable mold plate
[0149] 3 Stationary mold plate [0150] 4 Resin composition [0151] 5
Pinpoint gate [0152] 6 Joining face [0153] 7 Composite [0154] 10
Metallic mold for injection joining
* * * * *