U.S. patent application number 10/568527 was filed with the patent office on 2007-08-16 for resin composition for fuel cell member.
Invention is credited to Yutaka Atsumi, Hidenori Ichikawa, Hiroyuki Muramatsu, Toshihide Nara, Yukihiro Tsuchiya.
Application Number | 20070191528 10/568527 |
Document ID | / |
Family ID | 34191106 |
Filed Date | 2007-08-16 |
United States Patent
Application |
20070191528 |
Kind Code |
A1 |
Nara; Toshihide ; et
al. |
August 16, 2007 |
Resin composition for fuel cell member
Abstract
There is provided a resin composition for a fuel cell member
which givens only a small amount of eluting ions. A resin
composition for a fuel cell member is formed to include 60 to 85 wt
% of the following polypropylene and 40 to 15 wt % of the following
talc: (1) polypropylene that is homopolypropylene,
blockpolypropylene or a blend of homopolypropylene and
blockpolypropylene, and has a melt flow rate of 2 to 40 g/10 min.;
(2) talc that has a whiteness degree of 96% or more, and an average
particle diameter of 4 to 10 .mu.m.
Inventors: |
Nara; Toshihide;
(Ichihara-shi, JP) ; Tsuchiya; Yukihiro;
(Ichihara-shi, JP) ; Ichikawa; Hidenori;
(Hamamatsu-shi, JP) ; Muramatsu; Hiroyuki;
(Hamamatsu-shi, JP) ; Atsumi; Yutaka;
(Hamamatsu-shi, JP) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Family ID: |
34191106 |
Appl. No.: |
10/568527 |
Filed: |
August 18, 2004 |
PCT Filed: |
August 18, 2004 |
PCT NO: |
PCT/JP04/11825 |
371 Date: |
September 25, 2006 |
Current U.S.
Class: |
524/451 |
Current CPC
Class: |
Y02B 90/10 20130101;
H01M 8/0267 20130101; H01M 8/1067 20130101; Y02T 90/32 20130101;
H01M 2300/0091 20130101; H01M 8/04067 20130101; C08L 23/12
20130101; Y02E 60/521 20130101; H01M 8/1048 20130101; Y02E 60/50
20130101; H01M 2250/30 20130101; Y02T 90/40 20130101; C08L 23/10
20130101; C08K 3/34 20130101; H01M 2250/20 20130101; Y02B 90/18
20130101; H01M 8/1023 20130101; C08L 23/10 20130101; C08L 2666/06
20130101 |
Class at
Publication: |
524/451 |
International
Class: |
C08K 3/34 20060101
C08K003/34 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2003 |
JP |
2003-295508 |
Claims
1. A resin composition for a fuel cell member comprising 60 to 85
wt % of the following polypropylene and 40 to 15 wt % of the
following talc: (1) polypropylene that is homopolypropylene,
blockpolypropylene or a blend of homopolypropylene and
blockpolypropylene, and has a melt flow rate of 2 to 40 g/10 min;
(2) talc that has a whiteness degree of 96% or more, and an average
particle diameter of4 to 10 .mu.m.
2. The resin composition for a fuel cell member according to claim
1, wherein the specific surface area of the talc is from 7 to 45
m.sup.2/g.
3. The resin composition for a fuel cell member according to claim
1, wherein when the total weight of the polypropylene and the talc
is regarded as 100 parts by weight, 0.01 to 1 part by weight of
carbon black is contained.
4. The resin composition for a fuel cell member according to claim
1, of which the electric conductivity is 2 .mu.S/cm or less.
5. The resin composition for a fuel cell member according to claim
1, wherein the fuel cell member is a fuel cell cooling circuit
member, a fuel cell ion exchanging component, or a fuel cell ion
exchanging cartridge.
Description
TECHNICAL FIELD
[0001] The invention relates to a resin composition for a fuel cell
composition.
BACKGROUND ART
[0002] Hitherto, SUS 316, which is generally said to exhibit the
lowest ion elution among metal materials, has been used as material
used in fuel cells or conventional secondary cell systems in order
to keep the cooling efficiency thereof or prevent pipes from being
blocked or corroded. However, the use of resin has been desired
from the viewpoint of molding workability or a height of the
flexibility of shapeability. The use of resin material such as
polypropylene or polyvinylidene fluoride has been investigated.
[0003] For example, in the case of fuel cells for automobiles, the
desire has been met by using material exhibiting a very low ion
elution (such as SUS 316) as material of heat exchangers or pipes
for circulating cooling liquid. In such a case, however, the shape
of the heat exchangers or the fabricating method thereof is
restricted. Thus, an increase in the size of the thermal
exchangers, an increase in the weight thereof, an increase in
costs, and others are caused. When metal material is used, metal
ions may elute out gradually from the material itself or corrosion
may advance from slight scratches in the surface thereof. There is
a method for coping therewith by subjecting the inside of a heat
exchanger to coating so as to decrease ion elution. However, if the
coating deteriorates, ions may elute out (see, for example,
Japanese Patent Application Laid-Open (JP-A) No. 2001-035519, and
JP-A No. 2003-123804).
[0004] Accordingly, it has been desired to develop resin material
as a substitute therefor. However, when the resin material is used
in the form of a simple substance, products therefrom warp
ordeform. Dependently on the use environment thereof, the resin
material is insufficient in heat resistance and rigidity. In order
to compensate for these, an attempt of incorporating a filler such
as talc, mica, glass fiber or calcium carbonate has been made.
[0005] Incidentally, these fillers are each inorganic powder
obtained by pulverizing a mineral, and thus metal ions elute easily
therefrom. In the case of, for example, talc, main components
thereof are silicon dioxide and magnesium oxide. Besides, aluminum
oxide, iron oxide, calcium oxide and so on are contained therein.
As eluting cations, silicon, magnesium, aluminum, iron, calcium and
other ions are detected. Besides, sodium, potassium and zinc ions
are detected as impurity cations, and chloride ions, hydroxide ions
and other ions are detected as anions. Accordingly, about composite
compositions into which a filler is incorporated, metal ions elute
out very much. Thus, the stability of physical properties thereof
over a long term is also poor. As a result, there is a problem that
the composition cannot be used.
[0006] Accordingly, an object of the invention is to provide a
resin composition for a fuel cell member which gives only a small
amount of eluting ions.
DISCLOSURE OF THE INVENTION
[0007] The inventors have paid attention to a combination of
polypropylene excellent in molding workability and talc, which is
an inexpensive filler having a high reinforcing effect, and have
eagerly investigated so as to find out that talc having specific
properties (whiteness, particle diameter, and specific surface
area) and the blend amount of the talc are adjusted, thereby
yielding a material from which metal ions are restrained from
eluting out, the material being stable in long-term physical
properties.
[0008] According to the invention, provided is the following resin
composition for a fuel cell member: [0009] 1. A resin composition
for a fuel cell member including 60 to 85 wt % of the following
polypropylene and 40 to 15 wt % of the following talc:
[0010] (1) polypropylene that is homopolypropylene,
blockpolypropylene or a blend of homopolypropylene and
blockpolypropylene, and has a melt flow rate of 2 to 40 g/10
min.;
[0011] (2) talc that has a whiteness degree of 96% or more, and an
average particle diameter of 4 to 10 82 m. [0012] 2. The resin
composition for a fuel cell member according to item 1, wherein the
specific surface area of the talc is from 7 to 45 m.sup.2/g. [0013]
3. The resin composition for a fuel cell member according to item 1
or 2, wherein when the total weight of the polypropylene and the
talc is regarded as 100 parts by weight, 0.01 to 1 part by weight
of carbon black is contained. [0014] 4. The resin composition for a
fuel cell member according to any one of items 1 to 3, wherein the
electric conductivity is 2 .mu.S/cm or less. [0015] 5. The resin
composition for a fuel cell member according to any one of items 1
to 4, wherein the fuel cell member is a fuel cell cooling circuit
member, a fuel cell ion exchanging member, or a fuel cell ion
exchanging cartridge.
[0016] According to the invention, it is possible to provide a
resin composition for a fuel cell member which gives only a small
amount of eluting ions.
BRIEF DESCRIPTION OF THE DRAWING
[0017] FIG. 1 is a view illustrating a device used to measure
electric conductivities in Examples and Comparative Examples.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The invention will be described hereinafter.
[0019] The polypropylene used in the resin composition of the
invention may be homopolypropylene, blockpolypropylene or a blend
of homopolypropylene and blockpolypropylene.
[0020] Examples of the comonomer of the blockpolypropylene include
ethylene and butene-1. Ethylene is particularly preferred.
[0021] The melt flow rate (MFR) of this polypropylene is from 2 to
40 g/10 min, preferably from 6 to 30 g/10 min, more preferably from
6 to 15 g/10 min. The MFR is measured in accordance with JIS K
7210-1999 under the following conditions: a resin temperature of
230.degree. C., and a load of 21.18 N (2.16 kgf).
[0022] If the MFR is less than 2 g/10 min, the moldability may
deteriorate. If the MFR is more than 40 g/10 min., the strength may
be poor.
[0023] In order to set the MFR into the above-mentioned range, for
example, it is advisable to adjust the molecular weight by the
adjustment of the concentration of hydrogen at the time of
polymerizing the polypropylene or some other operation, or
decompose it with peroxide.
[0024] The talc used in the resin composition of the invention has
a whiteness of 96% or more. The whiteness is measured in accordance
with JIS P 8123. The whiteness is preferably 97% or more, more
preferably 98% or more.
[0025] If the whiteness is less than 96%, the amount of eluting
ions may be large so that the resin composition cannot be used as a
composition for a fuel cell member. Additionally, the physical
stability over a long term may deteriorate.
[0026] In order to set the whiteness into the above-mentioned
range, for example, the producing district is selected or the talc
is pulverized, is washed to remove impurities or is subjected to
surface treatment.
[0027] The average particle diameter of the talc is from 4 to 10
.mu.m, preferably from 4.5 to 8 .mu.m, more preferably from 5 to 8
.mu.m. The average particle diameter can be measured by laser
analysis method.
[0028] If the average particle diameter is more than 10 .mu.m, the
elution-out of metal ions may increase. If it is less than 4 .mu.m,
there maybe the following possibility; The particle diameter is
fine and thus the dispersion of the talc into the polypropylene
deteriorates or the talc goes up as dust into the air at the time
of the production so that the handling ability may deteriorate.
[0029] In order to set the average particle diameter into the
above-mentioned range, for example, the talc is pulverized, is
powdered into fine particles by high-speed stirring, or is
subjected to classification for collecting specific particle
diameters.
[0030] The specific surface area of the talc is from 7 to 45
m.sup.2/g, preferably from 7 to 40 m.sup.2/g, more preferably from
30 to 40 m.sup.2/g. The specific surface area can be measured by
the BET method.
[0031] If the specific surface area is less than 7 m.sup.2/g, the
elution-out of metal ions may increase. If it is more than 45 m2/g,
there may be the following possibility; The dispersion of the talc
into the polypropylene deteriorates or the talc goes up as dust
into the air at the time of the production so that the handling
ability may deteriorate.
[0032] In order to set the specific surface area into the
above-mentioned range, for example, the talc is powdered into fine
particles by high-speed stirring, or is treated with a treating
agent for preventing re-aggregation.
[0033] In the resin composition of the invention, about the
composition ratio between the polypropylene and the talc, the
polypropylene:talc is 60-85 wt %:40-15 wt %, preferably 68-78 wt
%:32-22 wt %, more preferably 70-80 wt %:30-25 wt %.
[0034] If the amount of the talc is less than 15 wt %, the resin
composition may cave or warp when it is molded so that the rigidity
deteriorate. If it is more than 40 wt %, the amount of eluting ions
may be large and thus the composition may not be used as a
composition for a fuel cell member.
[0035] In order to color the resin composition of the invention
into black, the composition may contain carbon black. When the
total amount of the polypropylene and the talc is regarded as 100
parts by weight, the carbon black is preferably added thereto in an
amount of 0.01 to 1 part by weight.
[0036] The resin composition of the invention may contain other
additives as long as the properties thereof are not damaged. If
necessary, various additives may be added, examples of which
include reforming additives such as a dispersing agent, a lubricant
(such as magnesium stearate), a plasticizer, a flame retardant, an
antioxidant (such as a phenol based antioxidant, a
phosphorus-containing antioxidant or a sulfur-containing
antioxidant), an antistatic agent, a light stabilizer, an
ultraviolet absorber, a crystallization promoter (a nucleus-forming
agent), a foaming agent, a crosslinking agent, and an antibacterial
agent; pigments, dyes and other coloring agents (such as titanium
oxide, colcothar, azo pigments, anthraquinone pigments, and
phthalocyanine); particulate fillers such as calcium carbonate,
mica, and clay; fillers in a short fiber form, such as
wollastonite; and other additives such as whiskers such as
potassium titanate. These additives may be added when the
composition is produced, or the additives may be made into a
masterbatch (M/B) and added when the composition is produced.
[0037] The resin composition of the invention may be produced by
charging the above-mentioned components directly into an extruder.
The composition may be produced by kneading and dispersing all of
the components with a Mixing roll, a Banbury mixer, a kneader or
the like and then charging the resultant into an extruder. The
components may be dry-blended with a tumbler type blender, a
Henschel mixer, or a ribbon mixer. The composition can also be
produced by preparing an M/B of the above-mentioned components in
advance and incorporating the M/B by the above-mentioned method.
The method of preparing the M/B is preferred.
[0038] The resin composition of the invention can be preferably
used for a fuel cell member since the amount of eluting ions is
small.
[0039] The electric conductivity of the resin composition of the
invention is preferably 2 .mu.S/cm or less, more preferably from 2
to 0.5 .mu.S/cm. The electric conductivity can be measured by use
of extra pure water.
[0040] When the electric conductivity is 2 .mu.S/cm or less, the
amount of eluting ions is small and thus the composition can be
more preferably used as a composition for a fuel cell member.
[0041] When the resin composition of the invention is molded, a
known forming method can be used without any restriction. Examples
thereof include injection molding, extrusion molding, blow molding,
compression molding, injection compression molding,
gas-insufflating injection molding, and foaming injection molding.
Injection molding, compression molding, and injection compression
molding are particularly preferred.
[0042] Examples of the fuel cell member fabricated from the resin
composition of the invention include fuel cell members for
automobiles or household articles and peripheral members thereof.
The fuel cell member is, for example, a fuel cell cooling circuit
member, a fuel cell ion exchanging member, a fuel cell ion
exchanging cartridge, or the like.
EXAMPLES
Example 1
[0043] The following components were blended and the blend was
injection-molded into a molded product: [0044] (a) polypropylene
(PP) (J-784HV manufactured by Idemitsu Petrochemical Co., Ltd.,
block PP, MFR=12 g/10 minutes): 75 wt %, [0045] (b) talc (TP-A25
manufactured by Fuji Talc Industrial Co., Ltd., whiteness: 98%,
average particle diameter: 4.96 .mu.m, specific surface area: 40
m.sup.2/g, and residue on a 45 .mu.m sieve: 0.002%) 25 wt %, [0046]
(c) antioxidant (Adekastab A0-20 manufactured by Asahi Denka Co.,
Ltd): 0.2 part by weight, [0047] antioxidant (Yoshitomi DMTP,
manufactured by Yoshitomi Fine Chemical Co., Ltd.): 0.2 part by
weight, [0048] (d) magnesium stearate (AFCO CHEM MGS-1,
manufactured by Asahi Denka Co., Ltd): 0.2 part by weight, and
[0049] (e) carbon black M/B (50 wt % polypropylene M/B of Vulcan 9
manufactured by Cabot Corporation.): 0.5 part by weight.
[0050] The amounts of the (c) to the (e) are represented by values
of parts by weight when the total amount of the block PP and the
talc are regarded as 100 parts by weight.
[0051] Physical properties of this molded product were measured by
the following methods. The results are shown in Table 1.
(1) Measurement of the Electric Conductivity
[0052] A device illustrated in FIG. 1 was used to measure the
electric conductivity by the following steps: [0053] 1. Seven
samples 1 (64 mm.times.12.7 mm.times.3.2 mm) (one set) of each of
Examples and Comparative Examples were prepared. [0054] 2. A 500-mL
container 2 made of PFA (made of fluorine-contained resin) was
prepared. [0055] 3. The container 2 was subjected to
overflow-washing with pure water. [0056] 4. The container 2 was
subjected to shake-washing with pure water. [0057] 5. The container
2 was subjected to shake-washing with extra pure water. [0058] 6.
The container 2 was dried. [0059] 7. The container 2 was subjected
to shake-washing with extra pure water. [0060] 8. Each of the
samples 1 was subjected to cup-washing with extra pure water.
[0061] 9. The sample 1 was transferred to the container 2. [0062]
10. The container 2 and the sample 1 were together washed with
extra pure water. [0063] 11. Extra pure water 3 was put thereinto
up to an UP level line. [0064] 12. The sample was stirred at
80.degree. C. for 24 hours. [0065] 13. After a lapse of 10 hours,
the container 2 was taken out from the thermostat bath and then
cooled to ambient temperature. [0066] 14. An electric conductivity
meter 4 was checked.
[0067] Whenever the sample sets of each of Examples and Comparative
Examples were changed, the value of a blank wherein no sample was
put was also measured.
(2) Bending Strength
[0068] It was measured according to ASTM D790 (at 23.degree.
C.).
[0069] Sample piece: 127 mm.times.12.7 mm.times.3.2 mm
(3) Flexural Modulus
[0070] It was measured according to ASTM D790 (at 23.degree.
C.).
[0071] Sample piece: 127 mm.times.12.7 mm.times.3.2 mm
(4) Izod Impact Strength
[0072] It was measured according to ASTM D256 (at 23.degree.
C.).
[0073] Sample piece: 64 mm.times.12.7 mm.times.3.2 mm, with a
notch
(5) Thermal Aging Resistance
[0074] After the sample was kept at 150.degree. C. for 1200 hours,
the stretch retention rate thereof was measured. The tensile
strength was measured according to ASTM D638.
[0075] Sample piece: ASTM type I, dumbbell thickness: 3.2 mm
TABLE-US-00001 TABLE 1 Physical properties of talc Blended Average
Specific amounts in the composition Whiteness particle surface area
PP Talc Antioxidant Kind of PP (%) diameter (.mu.m) (m.sup.2/g) (wt
%) (wt %) (pbw*) Ex. 1 Block PP 98 4.96 40 75 25 0.4 Ex. 2 Block PP
98 4.96 40 70 30 0.4 Ex. 3 Block PP 97 5.83 30 75 25 0.4 Comp. Ex.
1 Block PP 98 4.96 40 90 10 0.4 Comp. Ex. 2 Block PP 98 4.96 40 55
45 0.4 Comp. Ex. 3 Block PP 91 20.6 6 75 25 0.4 Blended Physical
properties of the composition amounts in the composition Izod
Thermal Mg Carbon Electric Bending Flexural impact aging stearate
black M/B conductivity Strength modulus strength resistance (pbw)
(pbw) (.mu.S/cm) (MPa) (MPa) (J/m) (%) Ex. 1 0.2 0.5 1.1 3300 45 53
90 Ex. 2 0.2 0 1.5 3000 48 48 90 Ex. 3 0.2 0.5 1.8 3000 44 47 90
Comp. Ex. 1 0.2 0.5 1.2 2000 22 60 90 Comp. Ex. 2 0.2 0.5 2.2 4300
55 40 85 Comp. Ex. 3 0.2 0.5 2.4 3100 44 50 75 (pbw*): patr by
weight
Example 2
[0076] Production and measurement were performed in the same way as
in Example 1 except that the amount of the polypropylene was
changed from 75 wt % to 70 wt %, that of the talc was changed from
25 wt % to 30 wt % and that of the carbon black M/B was changed
from 0.5 part to 0 part in Example 1.
Example 3
[0077] Production and measurement were performed in the same way as
in Example 1 except that the talc in Example 1 (TP-A25 manufactured
by Fuji Talc Industrial Co., Ltd., whiteness: 98%, average particle
diameter: 4.96 .mu.m, specific surface area: 40 m2/g, and residue
on a 45 .mu.m sieve: 0.002%) was changed to talc (LMK-100
manufactured by Fuji Talc Industrial Co., Ltd., whiteness: 97%,
average particle diameter: 5.83 .mu.m, specific surface area: 30
m.sup.2/g, and residue on a 45 .mu.m sieve: 0.003%).
Comparative Example 1
[0078] Production and measurement were performed in the same way as
in Example 1 except that the amount of the polypropylene in Example
1 was changed from 75 wt % to 90 wt % and that of the talc was
changed from 25 wt % to 10 wt %.
Comparative Example 2
[0079] Production and measurement were performed in the same way as
in Example 1 except that the amount of the polypropylene in Example
1 was changed from 75 wt % to 55 wt % and that of the talc was
changed from 25 wt % to 45 wt %.
Comparative Example 3
[0080] Production and measurement were performed in the same way as
in Example 1 except that the talc in Example 1 (TP-A25 manufactured
by Fuji Talc Industrial Co., Ltd., whiteness: 98%, average particle
diameter: 4.96 .mu.m, specific surface area: 40 m.sup.2/g, and
residue on a 45 .mu.m sieve: 0.002%) was changed to talc (B-8
manufactured by Asada Milling Co., Ltd., whiteness: 91%, average
particle diameter: 20.6 .mu.m, specific surface area: 6 m.sup.2/g,
and residue on a 45 .mu.m sieve: 0.24%).
[0081] As is shown in Table 1, the electric conductivity of the
resin compositions of Examples was 2.0 .mu.S/cm or less. The
retention rate of the tensile strength thereof was 90% or more
according to the long-term thermal resistance test. Thus, the
physical properties thereof were maintained over a long term.
INDUSTRIAL APPLICABILITY
[0082] The resin composition for a fuel cell member of the
invention can be used for a fuel cell member.
* * * * *