U.S. patent application number 12/160865 was filed with the patent office on 2010-08-12 for electrically conductive gasket material.
This patent application is currently assigned to SEIREN CO., LTD.. Invention is credited to Hiroyasu Shimizu, Kiyotaka Takebayashi, Toru Takegawa, Yutaka Tanaka.
Application Number | 20100203789 12/160865 |
Document ID | / |
Family ID | 38287763 |
Filed Date | 2010-08-12 |
United States Patent
Application |
20100203789 |
Kind Code |
A1 |
Takebayashi; Kiyotaka ; et
al. |
August 12, 2010 |
ELECTRICALLY CONDUCTIVE GASKET MATERIAL
Abstract
An electrically conductive material for an electrically
conductive gasket is to be provided, the electrically conductive
material permitting easy manufacture of an electrically conductive
gasket in an arbitrary shape, having a cushioning property and
making it possible to greatly diminish cutting wastes in punching
work and also greatly diminishing the formation of fray and fluff.
According to the present invention there are provided an
electrically conductive material comprising a metalized non-woven
fabric of a self-bonded continuous organic fiber, as well as an
electrically conductive material comprising a metalized, integrally
laminated composite sheet of both a non-woven fabric of a
self-bonded continuous organic fiber and an organic fiber structure
sheet.
Inventors: |
Takebayashi; Kiyotaka;
(Fukui-shi, JP) ; Takegawa; Toru; (Fukui-shi,
JP) ; Tanaka; Yutaka; (Sabae-shi, JP) ;
Shimizu; Hiroyasu; (Sabae-shi, JP) |
Correspondence
Address: |
GREER, BURNS & CRAIN
300 S WACKER DR, 25TH FLOOR
CHICAGO
IL
60606
US
|
Assignee: |
SEIREN CO., LTD.
Fukui
JP
KB SEIREN, LTD.
Fukui
JP
|
Family ID: |
38287763 |
Appl. No.: |
12/160865 |
Filed: |
January 17, 2007 |
PCT Filed: |
January 17, 2007 |
PCT NO: |
PCT/JP2007/051025 |
371 Date: |
April 27, 2010 |
Current U.S.
Class: |
442/377 ;
442/414 |
Current CPC
Class: |
B32B 5/26 20130101; H05K
9/0015 20130101; B32B 27/02 20130101; D06M 2200/00 20130101; B32B
27/36 20130101; D06M 11/83 20130101; B32B 27/12 20130101; F16J
15/064 20130101; F16J 15/3284 20130101; B32B 27/16 20130101; B32B
27/32 20130101; Y10T 442/696 20150401; B32B 27/08 20130101; Y10T
442/655 20150401; H05K 9/009 20130101; F16J 15/102 20130101 |
Class at
Publication: |
442/377 ;
442/414 |
International
Class: |
D04H 13/00 20060101
D04H013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 17, 2006 |
JP |
2006-009207 |
Claims
1. An electrically conductive material comprising a metalized
non-woven fabric of a self-bonded continuous organic fiber.
2. An electrically conductive material as set forth in claim 1,
wherein the organic fiber is a synthetic fiber.
3. An electrically conductive material as set forth in claim 2,
wherein the synthetic fiber is at least one member selected from
the group consisting of urethane fiber, polyolefin fiber, nylon
fiber and polyester fiber.
4. An electrically conductive material as set forth in claim 1,
wherein the non-woven fabric of a self-bonded continuous organic
fiber is obtained by a melt-blow method or a spun-bonding
method.
5. An electrically conductive material as set forth in claim 1,
wherein the metal is at least one metal selected from the group
consisting of gold, silver, copper, nickel, tin and cobalt.
6. An electrically conductive material as set forth in claim 1,
wherein the metallization is performed by an electroless plating
method or an electroplating method.
7. An electrically conductive material comprising a metalized,
integrally laminated composite sheet of both a non-woven fabric of
a self-bonded continuous organic fiber and an organic fiber
structure sheet.
8. An electrically conductive material as set forth in claim 7,
wherein the organic fiber structure sheet is a non-woven, woven or
knitted fabric of an organic fiber having a modulus of membrane
elasticity of 100 N/in or more.
9. An electrically conductive material as set forth in claim 7,
wherein the organic fiber in the organic fiber structure sheet is a
synthetic fiber.
10. An electrically conductive material as set forth in claim 9,
wherein the synthetic fiber is at least one member selected from
the group consisting of urethane fiber, polyolefin fiber, nylon
fiber and polyester fiber.
11. An electrically conductive material as set forth in claim 7,
wherein the non-woven fabric of a self-bonded continuous organic
fiber is obtained by a melt-blow method or a spun-bonding
method.
12. An electrically conductive material as set forth in claim 7,
wherein the metal is at least one metal selected from the group
consisting of gold, silver, copper, nickel, tin and cobalt.
13. An electrically conductive material as set forth in claim 7,
wherein the metallization is performed by an electroless plating
method or an electroplating method.
14. An electrically conductive material comprising any of the
electrically conductive materials described in claim 1 and resin
applied thereto.
15. An electrically conductive gasket part fabricated by punching
any of the electrically conductive materials described in claim 1
to 14.
16. An electrically conductive material as set forth in claim 8,
wherein the organic fiber in the organic fiber structure sheet is a
synthetic fiber.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an electrically conductive
gasket material to be used for shielding unnecessary radiant
electromagnetic waves generated from the exterior or shielding
electromagnetic waves leaking from the interior.
BACKGROUNDS OF THE INVENTION
[0002] Devices utilizing electronics, i.e., so-called electronic
devices, such as personal computers, video games and portable
telephones have recently come to be utilized widely and have spread
also in general home life. With expansion of use of such electronic
devices from industrial use to general use, there frequently occur
problems such as malfunctions of other electronic devices caused by
electromagnetic waves leaking from the electronic devices in
question or radio troubles of communication devices also caused by
such leaking electromagnetic waves. These problems have come be
taken up as serious problems also in mass communication.
[0003] In such a social environment, in fields related to the
electronic industry there is an increasing demand for an
electromagnetic wave shielding material which exhibits an
outstanding effect for preventing various troubles caused by
electronic waves leaking from the aforesaid electronic devices.
[0004] Generally, the electromagnetic wave generated from a device
utilizing electronics and considered to be a matter of particular
issue is the electromagnetic wave leaking from a juncture of
constituent parts of a device housing or from a gap of an
opening/closing door attached to the device housing. Electrically
conductive gaskets having various shapes have been proposed for the
purpose of shielding such a leaking electromagnetic wave.
[0005] Among such electrically conductive gaskets, those having a
cushioning property and having an electrical conductivity equal to
that of metal have actually been used and proved to be effective to
a certain extent as shielding members of a structure which
satisfies the purpose of shielding electromagnetic waves. As
examples of such products there are
(1) a product (hereinafter referred to as a electrically conductive
cloth-wound gasket) comprising a synthetic resin foam of a
prismatic shape not plated with metal and a synthetic fiber fabric
(hereinafter referred to as an electrically conductive fiber
fabric) plated with metal wound round the synthetic resin foam, as
shown in U.S. Pat. No. 4,857,668, (2) a metalized, integrally
laminated, composite sheet (hereinafter referred to as an
electrically conductive foam sheet) comprising an organic fiber
structure sheet and a synthetic resin porous sheet, as disclosed in
JP 3306665B, and (3) a metalized non-woven fabric (hereinafter
referred to an electrically conductive non-woven fabric) of organic
fibers, as disclosed in JP 7-166467A.
DISCLOSURE OF THE INVENTION
Objects of the Invention
[0006] Among the electrically conductive gaskets referred to above,
as to the electrically conductive cloth-wound gasket, a limit is
encountered in point of gasket shape. More particularly, the gasket
is columnar having a quadrangular or L-shaped section and it is
difficult to fabricate a so-called deformed type of gasket such as
a doughnut- or petal-shaped gasket. Besides, it is difficult to
make fiber fray from a cut face nil. An aluminum foil gasket using
aluminum foil instead of an electrically conductive fiber fabric as
means for avoiding such fiber fray is available on the market, but
since the foil is a metal foil, it becomes hard and repeated
compression causes breakage of the aluminum foil. Thus, the use of
such an aluminum foil gasket is limited.
[0007] The electrically conductive foam sheet is advantageous in
that the deformed type gasket can be fabricated easily by mere
punching into an arbitrary shape because even the interior
synthetic resin porous sheet is metalized. However, there remains
the problem that there occurs dropping of metalized organic fiber
wastes and porous sheet wastes during punching and the dropped
wastes are suspended in the interior of the electronic device
concerned, with a consequent fear of damage to the device by
electric shorting or of occurrence of a fire.
[0008] The electrically conductive non-woven fabric involves the
same problems as the above electrically conductive foam sheet;
besides, the bonding force between constituent fibers of the
non-woven fabric is low and fluff occurs on the material surface in
practical use, which also causes the foregoing electric
shorting.
[0009] As to the parts and materials described in the foregoing
three patent literatures, there is a fear of fiber fray, dropping
of wastes and fluff, but no problem in practical use has been
reported, in such large-sized electrical products as desktop
personal computers and plasma displays. However, in mobile
electronic devices typified by portable telephones, a large
physical load such as a dropping or knocking load is imposed
thereon, so that fiber fray or dropping of wastes and fluff are
likely to become fatal. For this reason the parts and materials in
question are often not adopted.
[0010] It is an object of the present invention to solve the
above-mentioned problems of the prior art and provide an
electrically conductive material easy to manufacture and capable of
forming an electromagnetic wave shielding material of high
quality.
SUMMARY OF THE INVENTION
[0011] The construction of the present invention is as follows.
(1) An electrically conductive material comprising a metalized
non-woven fabric of a self-bonded continuous organic fiber. (2) An
electrically conductive material as described in (1), wherein the
organic fiber is a synthetic fiber. (3) An electrically conductive
material as described in (2), wherein the synthetic fiber is at
least one member selected from the group consisting of urethane
fiber, polyolefin fiber, nylon fiber and polyester fiber. (4) An
electrically conductive material as described in (1), wherein the
non-woven fabric of a self-bonded continuous organic fiber is
obtained by a melt-blow method or a spun-bonding method. (5) An
electrically conductive material as described in (1), wherein the
metal is at least one metal selected from the group consisting of
gold, silver, copper, nickel, tin and cobalt. (6) An electrically
conductive material as described in (1), wherein the metallization
is performed by an electroless plating method or an electroplating
method. (7) An electrically conductive material comprising a
metalized, integrally laminated composite sheet of both a non-woven
fabric of a self-bonded continuous organic fiber and an organic
fiber structure sheet. (8) An electrically conductive material as
described in (7) wherein the organic fiber structure sheet is a
non-woven, woven or knitted fabric of an organic fiber having a
modulus of membrane elasticity of 100 N/in or more. (9) An
electrically conductive material as described in (7) or (8),
wherein the organic fiber in the organic fiber structure sheet is a
synthetic fiber. (10) An electrically conductive material as
described in (9), wherein the synthetic fiber is at least one fiber
selected from the group consisting of urethane fiber, polyolefin
fiber, nylon fiber and polyester fiber. (11) An electrically
conductive material as described in (7), wherein the non-woven
fabric of a self-bonded continuous organic fiber is obtained by a
melt-blow method or a spun-bonding method. (12) An electrically
conductive material as described in (7), wherein the metal is at
least one metal selected from the group consisting of gold, silver,
copper, nickel, tin and cobalt. (13) An electrically conductive
material as described in (7), wherein the metallization is
performed by an electroless plating method of an electroplating
method. (14) An electrically conductive material comprising any of
the electrically conductive materials described in (1) to (13) and
resin applied thereto. (15) A electrically conductive gasket part
fabricated by punching any of the electrically conductive materials
described in (1) to (14).
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a tensile force--strain curve of an organic fiber
structure sheet.
[0013] FIG. 2 is a perspective view of an electrically conductive
material comprising a metalized non-woven fabric of a self-bonded
continuous organic fiber in the present invention.
[0014] FIG. 3 is a perspective view of metalized, integrally
laminated, composite sheet of both a non-woven fabric of a
self-bonded continuous organic fiber and an organic fiber structure
sheet in the present invention.
[0015] FIG. 4 is a perspective view of an electrically conductive
material of a metalized polyurethane foam described in Comparative
Example 1.
[0016] FIG. 5 is a perspective view of an electrically conductive
material comprising a metalized, integrally laminated, composite
sheet of both a polyurethane foam and a spun-bonded non-woven
fabric of a polyester fiber in Comparative Example 2.
[0017] FIG. 6 is a perspective view of an electrically conductive
material comprising a metalized spun lace non-woven fabric of a
polyester staple fiber in Comparative Example 3.
[0018] The following are the contents of reference numerals used in
the drawings: [0019] 1 . . . the whole of an electrically
conductive material comprising a metalized non-woven fabric of a
self-bonded continuous organic fiber [0020] 2 . . . a non-woven
fabric of a self-bonded continuous organic fiber [0021] 3 . . . the
whole of an electrically conductive material comprising a
metalized, integrally laminated composite sheet of both a non-woven
fabric of a self-bonded continuous organic sheet and an organic
fiber structure sheet [0022] 4 . . . organic fiber structure sheet
[0023] 5 . . . the whole of an electrically conductive material
comprising a metalized polyurethane foam [0024] 6 . . .
polyurethane foam [0025] 7 . . . the whole of an electrically
conductive material comprising a metalized, integrally laminated
composite sheet of both a polyurethane foam and an organic fiber
structure sheet [0026] 8 . . . the whole of an electrically
conductive material comprising a metalized spun lace non-woven
fabric [0027] 9 . . . spun lace non-woven fabric
EMBODIMENTS OF THE INVENTION
[0028] A typical example of the electrically conductive gasket
material of the present invention has such a sectional structure as
shown in FIGS. 2 and 3. In FIG. 2, the reference numeral 1 denotes
the whole of an electrically conductive gasket material and numeral
2 denotes a non-woven fabric of a self-bonded continuous fiber,
with a metal coating being formed even up to a fiber surface in the
interior of the non-woven fabric.
[0029] In FIG. 3, numeral 3 denotes the whole of an electrically
conductive gasket material, numeral 2 denotes a non-woven fabric of
a self-bonded continuous fiber and numeral 4 denotes an organic
fiber structure sheet, with a metal coating being formed even up to
a fiber surface in the interior of the non-woven fabric 2 and a
fiber surface in the interior of the organic fiber structure sheet
4.
[0030] The electrically conductive gasket material of the present
invention has a structural characteristic such that the fibers
which constitute the non-woven fabric (FIG. 2) and the non-woven
fabric--organic fiber structure sheet (FIG. 3) before metallization
were replaced as they were with metalized fibers. That is, the
gasket material in question has air-permeability like that before
metallization and the fibers which constitute the non-woven fabric
and the organic fiber structure sheet are each covered with an
extremely thin metal coating so as not to be influenced by the
ambient atmosphere.
[0031] By incorporating a flame retardant in the electrically
conductive material of the present invention it is possible to
realize an electrically conductive material having flame retardancy
and suitable as an electromagnetic wave shielding gasket.
[0032] The non-woven fabric of a self-bonded continuous fiber used
in the present invention is preferably obtained by making at least
one thermoplastic resin web-like, the at least one thermoplastic
resin being selected from the group consisting of polyurethane,
polyolefin (including elastomeric polypropylene and
propylene-ethylene copolymer), nylon and polyester (including
polyester elastomer). The process for manufacturing of non-woven
fabric is not specially limited insofar as it is such a known
method as spunbonding method or a melt blown method, with the melt
blown method being particularly preferred.
[0033] A general melt-blow spinning method will now be described. A
thermoplastic resin is extruded through an extruder, then molten
polymer is weighed by a gear pump and is discharged from spinning
nozzle holes arranged in a row. Heated high-temperature gas is
jetted at high speed from slits formed on both sides of the nozzle
holes and the polymer extruded from the nozzle holes is thinned and
cooled by the high-speed gas flow to form continuous filaments. The
thinned filaments are separated from the gas flow on a moving
conveyor net collector device substantially without being bunched
and are stacked on the net. The stacked filaments are maintained in
the stacked state with their own heat and contacts thereof are
fusion-bonded. The filaments, after being stacked on the collector
device, may be bonded by the application of heat and pressure using
rollers or the like before or after cooling and solidifying. In
order to strengthen the bonding of filament-to-filament contact
points it is preferable that the spacing from the spinning nozzle
to the stacked position on the collector device be not so long. The
said spacing is preferably 10 to 100 cm, more preferably 20 to 50
cm. A gas flow guide passage may be formed between the nozzle and
the collector device, but may be omitted.
[0034] In the non-woven fabric of a self-bonded continuous fiber
used in the present invention, it is preferable that the filaments
be stacked in a disintegrated state substantially without being
bunched in their longitudinal direction. If monofilaments are fused
in a bunched state without being disintegrated, the non-woven
fabric becomes less uniform and its flexibility is greatly
impaired.
[0035] In the non-woven fabric of a self-bonded continuous fiber
used in the present invention, the fiber diameter is preferably
1-50 .mu.m, more preferably 5-30 .mu.m, weight is preferably
20-1200 g/m.sup.2, elongation is preferably 100% or more, more
preferably 300% or more, strength (25 mm width, 1 g/m.sup.3) is
preferably 6 cN or more, more preferably 10 cN or more, per unit
weight, though it differs depending on thickness, and tear strength
(25 mm width, 1 g/m.sup.3) is preferably 5 cN or more, more
preferably 7.5 cN or more, per unit weight. Further, a recovery
rate at 100% elongation is preferably 70% or more, more preferably
80% or more. Thus, the non-woven fabric in question is superior in
the recovery rate from elongation. Another feature is that the
non-woven fabric possesses extremely excellent air-permeability and
soft feeling. The air-permeability is preferably 5-200
cc/cm.sup.2/s.
[0036] Preferably, an organic fiber structure sheet is integrally
laminated to the non-woven fabric of a self-bonded continuous fiber
in the present invention for the purpose of imparting dimensional
stability in plating process to the non-woven fabric. This is for
preventing elongation in the advancing direction caused by the
imposition of tension on the fabric in the plating process and for
preventing eventual difficulty of controlling the thickness to a
desired thickness.
[0037] As examples of the method for integrally laminating the
non-woven fabric of a self-bonded continuous fiber and the organic
fiber structure sheet to each other to afford a composite sheet
there are mentioned a method wherein an adhesive is applied to the
surface of either the non-woven fabric or the organic fiber
structure sheet and the other is laminated and bonded to the
adhesive and a so-called fusion-bonding method wherein in case of
the non-woven fabric of a self-bonded continuous fiber being a
heat-melting fabric, at least a part of the surface of the
non-woven fabric is heat-melted and immediately thereafter the
organic fiber structure sheet is laminated and bonded to the
non-woven fabric.
[0038] As examples of the organic fiber structure sheet used in the
present invention there are mentioned such textile fabrics as
woven, knitted and non-woven fabrics formed by using organic
fibers.
[0039] As examples of organic fibers there are mentioned such
chemical fibers as synthetic, semisynthetic and regenerated fibers,
as well as such natural fibers as vegetable fibers and animal
fibers. Particularly preferred are such synthetic fibers as
polyamide fibers, e.g., nylon 6 and nylon 66, and polyester fibers,
e.g., polyethylene terephthalate. Above all, polyester fibers such
as polyethylene terephthalate fibers are preferred taking
productivity, handleability and cost into account.
[0040] For example, in the case of polyester fibers, a
multifilament yarn with a monofilament size of 0.11-5.6 dtex is
preferred. If the monofilament size is smaller than 0.11 dtex, a
sufficient strength will not be obtained, while if it is larger
than 5.6 dtex, the fabric will become hard and there is a fear that
the flexibility of the fabric may be impaired.
[0041] As the kind of the textile fabric, non-woven fabric is more
preferred. The weight of the textile fabric is preferably 10-100
g/m.sup.2.
[0042] Taking dimensional stability into account, it is preferable
for the organic fiber structure sheet to have a modulus of membrane
elasticity of 100 N/in or more.
[0043] For forming a metal coating onto the non-woven fabric of a
self-bonded continuous organic fiber or the integrally laminated
composite sheet there may be adopted a known method such as, for
example, sputtering or vacuum deposition. Electroless plating is
preferred taking unifying of the metal layer as well as electrical
conductivity and shielding property into account. After performing
a conventional pre-treatment such as the application of a catalyst
or activation for electroless plating, there is performed
electroless plating or both electroless plating and subsequent
electroplating, using a desired metal such as, for example, gold,
silver, copper, nickel, tin, cobalt, copper+nickel, copper+silver,
nickel+cobalt, or nickel+copper+nickel.
[0044] If metallization is performed by electroless plating or a
combination of both electroless plating and electroplating, in
comparison with the case where metal foil is laminated to one
surface of the non-woven fabric of a self-bonded continuous organic
fiber, a metal coating is formed uniformly on the surface portion
of each of the fibers present in the interior of the texture of the
non-woven fabric and a continuous metal coating is formed also in
the thickness direction. This is effective in decreasing the volume
resistance value which is important for the electrically conductive
gasket material.
[0045] The thickness of the metal coating is preferably 0.01-2
.mu.m. If the thickness is smaller than 0.01 .mu.m, a satisfactory
shielding property may not be obtained, while if it is larger than
2 .mu.m, not only it is impossible to expect a further improvement
of shieldability but also there is a fear that the metal coating
may become easier to fall off. In case of using electroless plating
or a combination of both electroless plating and electroplating for
the formation of a metal coating, it is easy to obtain a desired
metal coating thickness and it is possible to form the metal
coating without stopping up voids which the non-woven fabric of a
self-bonded continuous organic fiber possesses. This is preferable
because the cushioning performance of the gasket material is not
impaired.
[0046] For diminishing peel-off of the metal layer from the
non-woven fabric of a self-bonded organic fiber or from the
integrally laminated composite sheet it is preferable that the
gasket base material be coated with resin after application of the
metal layer to the base material and before cutting. The resin to
be used is not specially limited for example to a thermoplastic
resin, but acrylic resin is preferred taking processability and
flexibility into account. As a resin applying method there may be
adopted a conventional known method such as, for example,
impregnation or coating.
EXAMPLES
[0047] The present invention will be described below by way of
working examples thereof, but the invention is not limited to the
following working examples. Non-woven fabrics obtained in the
following working and comparative examples were evaluated by the
following methods.
MFR of Resin:
[0048] Measured in accordance with JIS K 7210 at 230.degree. C. and
a load of 21.18N.
Average Fiber Diameter of Non-woven Fabric:
[0049] Using a scanning electron microscope (SEM), an enlarged
(50.times.) photograph of a non-woven fabric surface was taken,
then the diameters of fifty fibers were measured and a mean value
thereof was used an average fiber diameter.
Weight of Non-woven Fabric:
[0050] Measured in accordance with JIS L1906 "General Filament
Non-woven Fabric Testing Method." As the weight, a 100)(100 mm test
piece was sampled and the weight thereof was measured and converted
to a value per m.sup.2. Strength & Elongation of Non-woven
Fabric:
[0051] Measured in accordance with JIS L1906 "General Filament
Non-woven Fabric Testing Method." A test piece having a width of 25
mm and a length of 200 mm was sampled and fixed to a tension tester
(manufactured by Orientec) while setting the chuck-to-chuck spacing
at 100 mm. The test piece was stretched at a pulling rate of 300
mm/min and strength (25 mm width, 1 g/m.sup.3, per unit weight) and
elongation were measured at breakage of the test piece.
Air-Permeability of Non-woven Fabric:
[0052] Measured in accordance with Frazil Form Method defined in
JIS L1906 "General Filament Non-woven Fabric Testing Method." A
test piece of about 200.times.200 mm was sampled and measured for
air-permeability with use of an air-permeability tester (a product
of TEXTEST).
Elongation Recovery Rate of Non-woven Fabric:
[0053] Measured in accordance with JIS L1096 "General Fabric
Testing Method." The recovery rate in the evaluation made according
to the present invention is a recovery rate at 100% elongation. A
test piece having a width of 25 mm and a length of 200 mm was
sampled and fixed to a tension tester (manufactured by Orientec)
while setting the chuck-to-chuck spacing at 100 mm. The test piece
was stretched up to 100% at a pulling rate of 300 mm/min and then
the cross head was returned to its original position at the same
pulling rate as in stretching to make zero the stress imposed on
the non-woven fabric. The test piece was again stretched up to 100%
at the same pulling rate as above and a stretched length of the
non-woven fabric at a time point of re-starting of stress loading
was assumed to be L mm. An elongation recovery rate was determined
in accordance with the following equation:
Elongation Recover Rate (%)=((100-L)/100).times.100
Modulus of Membrane Elasticity:
[0054] Measured in accordance with JIS L1906 "General Filament
Fiber Non-woven Fabric Testing Method." A test piece having a width
of 25 mm and length of 200 mm was sampled and fixed to a tension
tester (manufactured by Shimadzu Corp.) while setting the
chuck-to-chuck spacing at 100 mm. The test piece was stretched at a
pulling rate of 300 mm/min and a modulus of membrane elasticity was
calculated from the gradient of S-S curve and in accordance with
the following equation:
E=Fm/(.epsilon.m/100) [0055] E . . . modulus of membrane elasticity
[N/in] [0056] F . . . tensile force [N/in] [0057] .epsilon. . . .
strain [%] [0058] m . . . a point at which the relation between
tensile force F and strain c maintains a rectilinear relation
[0059] Fm . . . tensile force at point m [0060] .epsilon.m . . .
strain at point m
Thickness:
[0061] Measured in accordance with JIS L-1098. [0062] Measuring
device . . . a constant pressure thickness measuring device TYPE
PF-11 (manufactured by TECLOCK Co.)
Stress at 50% Compression:
[0063] A sample cut to a size of 10 mm square was put on a pressure
bearing board and compressed at a rate of 0.5 mm/sec, then the load
corresponding to a sample thickness of 50% of the initial thickness
was read and divided by the area of the sample to obtain a pressure
at 50% compression.
Surface Resistance:
[0064] Both ends of a test piece having a width of 120 mm and a
length of 120 mm were sandwiched in between 100 mm wide electrodes
and a resistance value across the 100 mm spacing was measured.
Volume Resistance:
[0065] A test piece having a width of 120 mm and a length of 120 mm
was sandwiched in between copper plates each having a width of 100
mm, a length of 100 mm and a weight of 3 kg and a resistance value
between the copper plates was measured.
Cutting Wastes:
[0066] The occurrence of wastes when cutting each sample with
scissors was checked visually.
[0067] Very Good: Cutting wastes occurred little.
[0068] Good: Cutting wastes occurred a little.
[0069] Not Bad: Cutting wastes occurred.
[0070] Bad: Cutting wastes occurred conspicuously.
Fray & Fluff:
[0071] Fray and fluff of fibers when cutting each sample with
scissors were checked visually.
[0072] Good: There is neither fray nor fluff of fibers.
[0073] Not Bad: There are a few fray and fluff of fibers.
[0074] Bad: There are fray and fluff of fibers.
Example 1
[0075] A propylene-ethylene copolymer (VM2330, a product of Exxon
Mobile, MFR: 300) was melt-kneaded in an extruder at 190.degree.
C., then weighed by a gear pump and discharged from a melt brown
nozzle having 0.5 mm dia. holes arranged in one row at 2 mm pitch.
The polymer was extruded at a discharge condition of 0.96 g/min per
nozzle hole and was thinned and solidified with heated air
(236.degree. C., 9 Nl/cm/min) blown off from both sides of the
nozzle to form 20 .mu.m dia. filaments. The filaments were blown
onto a moving conveyor net located at a position of 20 cm from the
nozzle and at the same time were sucked in a suction quantity
(sucking rate=6 m/s) three times as large as the heated air by
means of a suction device disposed just under the conveyor net,
affording a polyolelfin-based elastic fiber non-woven fabric having
a weight of 200 g/m.sup.2, an elongation of 460%, a strength of
13.8 N and a 100% elongation recovery rate of 82%.
[0076] The raw fabric thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the fabric was immersed in borofluoric acid having an
acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the fabric was immersed in an
electroless copper plating solution consisting of 7.5 g/L of copper
sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt at
30.degree. C. for 5 minutes and therewafter washed with water.
Then, the fabric was immersed in an electroless nickel plating
solution consisting of 30 g/L of nickel sulfate, 20 g/L of sodium
hypophoshite and 50 g/L of ammonium citrate at 35.degree. C. for 5
minutes, allowing nickel to be laminated to the fabric, followed by
washing with water. As shown in Table 1, there was a little
dropping of cutting wastes. Particularly, there was no large waste
derived from fibers, with only a small amount of formation of metal
powder small in particle diameter.
Example 2
[0077] 30% of polypropylene resin (a product of Idemitsu
Petrochemical Co., Ltd.) was added to the propylene-ethylene
copolymer (VM2330, a product of Exxon Mobile) described in Example
1 and both were melt-kneaded in an extruder at 210.degree. C.,
followed by the same operations as in Example 1, to prepare
non-woven fabric. The non-woven fabric had a fiber diameter of 20
.mu.m, a weight of 200 g/m.sup.2, an elongation of 420%, a strength
of 14.7N and a 100% elongation recovery rate of 80%. Spinning
conditions were good.
[0078] The raw fabric thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the fabric was immersed in borofluoric acid having an
acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the fabric was immersed in an
electroless copper plating solution consisting of 7.5 g/L of copper
sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt at
30.degree. C. for 5 minutes and thereafter washed with water. Then,
the fabric was immersed in an electroless nickel plating solution
consisting of 30 g/L of nickel sulfate, 20 g/L of sodium
hypophosphite and 50 g/L of ammonium citrate at 35.degree. C. for 5
minutes, allowing nickel to be laminated to the fabric, followed by
washing with water. As shown in Table 1, there was a little
dropping of cutting wastes. Particularly, there was no large waste
derived from fibers, with only a small amount of formation of metal
powder small in particle diameter.
Example 3
[0079] 30% of polypropylene resin (a product of Idemitsu
Petrochemical Co., Ltd.) was added to the propylene-ethylene
copolymer (VM2330, a product of Exxon Mobile) described in Example
1 and both were melt-kneaded in an extruder at 210.degree. C.,
followed by the same operations as in Example 1, to prepare
non-woven fabric. The non-woven fabric had a fiber diameter of 20
.mu.m, a weight of 200 g/m.sup.2, an elongation of 420%, a strength
of 14.7N and a 100% elongation recovery rate of 80%. Spinning
conditions were good.
[0080] Next, the raw fabric thus obtained was bonded to spun-bonded
non-woven fabric (weight 40 g/m.sup.2, modulus of membrane
elasticity 3000 N/in) of polyester filaments (monofilament size:
2.2 dtex) to afford a 0.8 mm thick composite.
[0081] The composite thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the fabric was immersed in borofluoric acid having an
acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Then, the composite was immersed in
an electroless copper plating solution consisting of 7.5 g/L of
copper sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt
at 30.degree. C. for 5 minutes and thereafter washed with water.
Subsequently, the composite was immersed in an electroless nickel
plating solution consisting of 30 g/L of nickel sulfate, 20 g/L of
sodium hypophosphite and 50 g/L of ammonium citrate at 35.degree.
C. for 5 minutes, allowing nickel to be laminated to the composite,
followed by washing with water. As shown in Table 1, there was a
little dropping of cutting wastes. Although large wastes derived
from spun bonding were formed in a small amount, the amount of
metal powder small in particle diameter was small.
Example 4
[0082] 30% of polypropylene resin (a product of Idemitsu
Petrochemical Co., Ltd.) was added to the propylene-ethylene
copolymer (VM2330, a product Exxon Mobile) described in Example 1
and both were melt-kneaded in an extruder at 210.degree. C.,
followed by the same operations as in Example 1, to prepare
non-woven fabric. The non-woven fabric had a fiber diameter of 20
.mu.m, a weight of 200 g/m.sup.2, an elongation of 420%, a strength
of 14.7N and a 100% elongation recovery rate of 80%. Spinning
conditions were good.
[0083] Next, polyester filaments (monofilament size: 2.8 dtex)
having a size of 30 d/12f were woven so as to have a weave density
of warp.times.weft=105 pc..times.75 pc./in to afford raw fabric of
an organic fiber structure sheet having a weight of 23 g/m.sup.2
and a modulus of membrane elasticity of 1200 N/n.
[0084] Then, for the removal of oil and for the impartment of
dimensional stability, the raw fabric thus obtained was subjected
to scouring and setting and was bonded to the non-woven fabric,
affording a 0.9 mm thick composite.
[0085] Subsequently, the composite thus obtained was immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with
water.
[0086] The composite was then immersed in borofluoric acid having
an acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the composite was immered in an
electroless copper plating solution consisting of 7.5 g/L of copper
sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt at
30.degree. C. for 5 minutes and thereafter washed with water.
Thereafter, the composite was immersed in an electroless nickel
plating solution consisting of 30 g/L of nickel sulfate, 20 g/L of
sodium hypophosphite and 50 g/L f ammonium citrate at 35.degree. C.
for 5 minutes, allowing nickel to be laminated to the composite,
followed by washing with water. As shown in Table 1, there was a
little dropping of cutting wastes. Particularly, there was no large
waste derived from fibers, with only a small amount of formation of
metal power small in particle diameter.
Example 5
[0087] 30% of polypropylene resin (a product of Idemitsu
Petrochemical Co., Ltd.) was added to the propylene-ethylene
copolymer (VM2330, a product of Exxon Mobile) described in Example
1 and both were melt-kneaded in an extruder at 210.degree. C.,
followed by the same operations as in Example 1, to prepare
non-woven fabric. The non-woven fabric had a fiber diameter of 20
.mu.m, a weight of 200 g/m.sup.2, an elongation of 420%, a strength
of 14.7N and a 100% elongation recovery rate of 80%. Spinning
conditions were good.
[0088] Next, the raw fabric thus obtained was bonded to spun-bonded
non-woven fabric (weigh 40 g/m.sup.2, modulus of membrane
elasticity 3000 N/in) of polyester filaments (monofilament denier:
2.0 d) to afford a 0.8 mm thick composite.
[0089] The composite thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the composite was immersed in borofluoric acid having
an acid concentration of 0.1 N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the composite was immersed in
an electroless copper plating solution consisting of 7.5 g/L of
copper sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt
at 30.degree. C. for 5 minutes and thereafter washed with water.
The composite was then immersed in an electroless nickel plating
solution consisting of 30 g/L of nickel sulfate, 20 g/L of sodium
hypophosphite and 50 g/L of ammonium citrate at 35.degree. C. for 5
minutes, allowing nickel to be laminated to the fabric, followed by
washing with water.
[0090] Then, the composite thus metalized was immersed in 40 g/L of
an aqueous acrylic resin (solids content 47%) and thereafter
dried.
[0091] As shown in Table 1, there was no dropping of cutting
wastes, nor was there any large waste derived from fibers, with
little formation of metal powder small in particle diameter.
Example 6
[0092] A polycarbonate-based polyurethane resin (a product of
Nippon Polyurethane Co.) was melt-kneaded in an extruder at
230.degree. C., followed by the same operations as in Example 1, to
prepare non-woven fabric. The non-woven fabric had a fiber diameter
of 20 .mu.m, a weight of 200 g/m.sup.2, an elongation of 480%, a
strength of 38.3N and a 100% elongation recovery rate of 90%.
Spinning conditions were good.
[0093] The raw fabric thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L of stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the fabric was immersed in borofluoric acid having an
acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the fabric was immersed in an
electroless copper plating solution consisting of 7.5 g/L of copper
sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt at
30.degree. C. for 5 minutes and thereafter washed with water. The
fabric was then immersed in an electroless nicking plating solution
consisting of 30 g/L of nickel sulfate, 20 g/L of sodium
hypophosphite and 50 g/l of ammonium citrate at 35.degree. C. for 5
minutes, allowing nickel to be laminated to the fabric, followed by
washing with water. As shown in Table 1, there was a little
dropping of cutting wastes. Particularly, there was no large waste
derived from fibers, with only a small amount of formation of metal
powder small in particle diameter.
Example 7
[0094] Polyester elastomer resin (P-40B, a product of Toyobo Co.,
Ltd., MFR: 10 (230.degree. C.)) was melt-kneaded in an extruder at
260.degree. C., followed by the same operations as in Example 1, to
prepare non-woven fabric. The non-woven fabric had a fiber diameter
of 20 .mu.m, a weight of 200 g/m.sup.2, an elongation of 640%, a
strength of 22.1N and a 100% elongation recovery rate of 88%.
Spinning conditions were good.
[0095] The raw fabric thus obtained was then immersed in a
40.degree. C. aqueous solution containing 0.3 g/L of palladium
chloride, 30 g/L f stannous chloride and 300 ml/L of 36%
hydrochloric acid for 2 minutes and thereafter washed with water.
Subsequently, the fabric was immersed in borofluoric acid having an
acid concentration of 0.1N at 30.degree. C. for 5 minutes and
thereafter washed with water. Next, the fabric was immersed in an
electroless copper plating solution consisting of 7.5 g/L of copper
sulfate, 30 ml/L of 37% formalin and 85 g/L of Rochelle salt at
30.degree. C. for 5 minutes and thereafter washed with water. The
fabric was then immersed in an electroless nickel plating solution
consisting of 20 g/L of nickel sulfate, 30 g/L of sodium
hypophosphite and 50 g/L of ammonium citrate at 35.degree. C. for 5
minutes, allowing nickel to be laminated to the fabric, followed by
washing with water. As shown in Table 1, there was no dropping of
cutting wastes, nor was there any large waste derived from fibers,
with little formation of metal powder small in particle
diameter.
Example 8
[0096] Polyester elastomer resin (P-30B, a product of Toyobo Co.,
Ltd., MFR: 14 (190.degree. C.)) was melt-kneaded in an extruder at
250.degree. C., followed by the same operations as in Example 1, to
prepare non-woven fabric. The non-woven fabric had a fiber diameter
of 20 .mu.m, a weight of 75 g/m.sup.2, an elongation of 520%, a
strength of 9.4N and a 100% elongation recovery rate of 87%.
Spinning conditions were good.
[0097] The raw fabric thus obtained was immersed in a 40.degree. C.
aqueous solution containing 0.3 g/L of palladium chloride, 30 g/L
of stannous chloride and 300 ml/L of 36% hydrochloric acid for 2
minutes and thereafter washed with water. Subsequently, the fabric
was immersed in borofluoric acid having an acid concentration of
0.1N at 30.degree. C. for 5 minutes and thereafter washed with
water. Next, the fabric was immersed in an electroless nick plating
solution consisting of 30 g/L of nickel sulfate, 20 g/L pf sodium
hypophosphite and 50 g/L of ammonium citrate at 35.degree. C. for 5
minutes and thereafter washed with water. The fabric was then
immersed in an electroless copper plating solution consisting of
7.5 g/L of copper sulfate, 30 ml/L of 37% formalin and 85 g/L of
Rochelle salt, allowing copper to be laminated to the fabric,
followed by washing with water. Further, the fabric was immersed in
an electroless nickel plating solution consisting of 30 g/L of
nickel sulfate, 20 g/L of sodium hypophosphite and 50 g/L of
ammonium citrate at 35.degree. C. for 5 minutes, allowing nickel to
be laminated to the fabric, followed by washing with water. As
shown in Table 1, there was no dropping of cutting waste, nor was
there any large waste derived from fibers, with little formation of
metal powder small in particle diameter.
Comparative Example 1
[0098] Metal was applied to a polyurethane foam having a thickness
of 1.2 mm and a density of 30 pc/in in the same manner as in
Example 1 to afford an electromagnetic wave shielding material. As
shown in Table 1, dropping of cutting wastes was conspicuous.
Particularly, large wastes derived from polyurethane foam were
observed and performance was not satisfactory.
Comparative Example 2
[0099] A polyurethane foam having a thickness of 1.2 mm and a
density of 30 pc/in and spun-bonded non-woven fabric (weight 40
g/m.sup.2, modulus of membrane elasticity 3000 N/in) of polyester
filaments (monofilament denier: 2.0d) were bonded together to
afford a 1.3 mm thick composite.
[0100] Then, metal was applied to the composite in the same manner
as in Example 1 to afford an electromagnetic shielding material. As
shown in Table 1, dropping of cutting wastes was conspicuous.
Particularly, large wastes derived from the fabric and polyurethane
foam were observed and performance was not satisfactory.
Comparative Example 3
[0101] Metal was applied to spun lace non-woven fabric (weight 50
g/m.sup.2) of polyester staple fibers (staple fiber denier: 2.0d)
in the same manner as in Example 1 to afford an electromagnetic
shielding material. As shown in Table 1, dropping of cutting wastes
was conspicuous. Particularly, large wastes derived from polyester
staple fibers were observed and performance was not
satisfactory.
TABLE-US-00001 TABLE 1 Surface Volume Thickness 50% Stress
Resistance Resistance Cutting (mm) (gf/cm.sup.2) Value (.OMEGA./sq)
Value (m.OMEGA.) Wastes Fray.Fluff Example 1 0.8 1958 0.03 2.9 Good
Good Example 2 0.8 2135 0.03 2.7 Good Good Example 3 0.9 2267 0.03
2.3 Good Good Example 4 0.9 2738 0.03 1.1 Good Not Bad Example 5
0.8 2183 0.03 1.0 Very Good Good Example 6 1.0 573 0.03 1.0 Good
Good Example 7 1.0 1352 0.02 0.2 Very Good Good Example 8 0.5 1013
0.02 0.3 Very Good Good Comparative 1.2 473 0.03 2.5 Bad Good
Example 1 Comparative 1.2 497 0.03 2.5 Bad Good Example 2
Comparative 0.5 677 0.03 2.5 Bad Bad Example 3
INDUSTRIAL APPLICABILITY
[0102] By using the electrically conductive material of the present
invention, in comparison with the electromagnetic wave shielding
material so far used in electronic devices, it is possible to
easily manufacture an electrically conductive gasket of an
arbitrary shape, a satisfactory cushioning property is attained,
the amount of cutting wastes in punching work can be decreased to a
great extent and so can be the formation of fray and fluff.
* * * * *