U.S. patent application number 09/737744 was filed with the patent office on 2001-05-03 for method of preparing a molded sealing composition for sealing against permeation of carbon dioxide gas.
This patent application is currently assigned to NOK Corporation. Invention is credited to Kobayashi, Osamu, Minagawa, Hironori, Ohta, Takashi, Ono, Shigeyuki, Tokumitsu, Hideyuki.
Application Number | 20010000788 09/737744 |
Document ID | / |
Family ID | 27289684 |
Filed Date | 2001-05-03 |
United States Patent
Application |
20010000788 |
Kind Code |
A1 |
Ono, Shigeyuki ; et
al. |
May 3, 2001 |
Method of preparing a molded sealing composition for sealing
against permeation of carbon dioxide gas
Abstract
An object of the present invention is to provide a molding
composition having an excellent properties to seal carbon dioxide.
The composition is made of fluoro thermoplastic elastomer having a
reinforcing filler such as carbon black or white carbon having a
particle diameter of not more than 100 nm. The composition can be
used as a sealing materials such as O-ring, oil seal, gasket, hose,
tube or diaphragm for sealing carbon dioxide.
Inventors: |
Ono, Shigeyuki;
(Ibaraki-ken, JP) ; Ohta, Takashi; (Ibaraki-ken,
JP) ; Tokumitsu, Hideyuki; (Ibaraki-ken, JP) ;
Minagawa, Hironori; (Ibaraki-ken, JP) ; Kobayashi,
Osamu; (Ibaraki-ken, JP) |
Correspondence
Address: |
JACOBSON PRICE HOLMAN & STERN
THE JENIFER BUILDING
400 SEVENTH STREET N W
WASHINGTON
DC
200042201
|
Assignee: |
NOK Corporation
Tokyo
JP
|
Family ID: |
27289684 |
Appl. No.: |
09/737744 |
Filed: |
December 18, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09737744 |
Dec 18, 2000 |
|
|
|
09175995 |
Oct 21, 1998 |
|
|
|
Current U.S.
Class: |
524/544 ;
524/496 |
Current CPC
Class: |
C08L 27/12 20130101;
C08K 3/013 20180101; C08K 3/013 20180101 |
Class at
Publication: |
524/544 ;
524/496 |
International
Class: |
C08L 027/12; C08K
003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 1997 |
JP |
9-316301 |
Feb 4, 1998 |
JP |
10-38056 |
Dec 12, 1997 |
JP |
9-362732 |
Claims
What is claimed is:
1. A molding composition for sealing carbon dioxide comprising a
fluoro thermoplastic elastomer and a filler having a particle size
of not more than 100 nm.
2. A molding composition for sealing carbon dioxide according to
claim 1, wherein said filler comprises a reinforcing filler.
3. A molding composition for sealing carbon dioxide according to
claim 1, wherein said filler comprises a non-reinforcing filer.
4. A molding composition for sealing carbon dioxide according to
claim 1, further comprising an organic peroxide crosslinking
agent.
5. A molding composition for sealing carbon dioxide according to
claim 1, further comprising an organic solvent.
6. A molded sealing composition for sealing carbon dioxide made of
the molding composition according to claim 1.
7. A hose or tube for sealing carbon dioxide made from a molding
composition according to claim 1.
8. A diaphragm for sealing carbon dioxide made from a molding
composition according to claim 1.
9. A molded sealing composition for sealing carbon dioxide
comprising a fluoro thermoplastic ealstomer and fluoro rubber,
wherein a surface of the fluoro rubber is covered by the fluoro
thermoplastic elastomer.
10. A molded sealing composition for sealing carbon dioxide
according to claim 8, wherein at least one kind of monomer unit is
copolymerized in both the fluoro rubber and the fluoro
thermoplastic elastomer.
11. A molded sealing composition for sealing carbon dioxide
according to claim 8, wherein a volume ratio of fluoro
thermoplastic elastomer in the molded sealing composition is in the
range of about 0.1 to 0.9.
12. A molded sealing composition for sealing carbon dioxide
according to claim 8, wherein a reinforcing filler having a
particle size of not more than 100 nm is used in the molded sealing
composition.
13. A molded sealing composition for sealing carbon dioxide
according to claim 8, wherein the molded sealing composition is
used as a part of a sealing device which is used for sealing
between relatively movable portions on one of which the sealing
device is held and at least a part of the molded sealing
composition made of the fluoro thermoplastic elastomer composition
is sealingly contacted with another relatively movable portion.
14. A sealing device for sealing carbon dioxide comprising; a
fluoro rubber, and a fluoro thermoplastic elastomer comprising a
fluoro thermoplastic elasomer and a reinforcing filler having a
particle diameter of not more than 100 nm, wherein a portion of a
carbon dioxide side of the sealing device is made of the fluoro
thermoplastic elasomer and at least one of a surface of the sealing
portion which sealingly contacts with a portion to be sealed is
covered by the fluoro thermoplastic elasomer which covers the
fluoro rubber.
15. A sealing device for sealing carbon dioxide according to claim
14, wherein the sealing device is used for an oil seal.
Description
BACKGROUND OF THE INVENTION
1. 1. Field of the Invention
2. The present invention relates to a molding composition for
sealing carbon dioxide, and a molded composition having an
excellent sealing property to be able to be used for sealing carbon
dioxide. Also, the present invention relates to a sealing device to
provide a seal between relatively movable portions on one of which
a portion of the sealing device is held, sealingly contacting with
another movable portion at a seal lip of the sealing device.
3. 2. Related Art
4. Conventionally, Freon gas has been used in almost all automobile
air-conditioners, refrigerators or the like as a coolant. But from
the point of view of environment disruption (the depletion of the
ozone layer, global warming or the like), new coolants other than
Freon gas have been recently extensively studied. Carbon dioxide is
considered to be one of a most hopeful next generation of coolants.
In the case of conventional Freon gas, sealing materials such as
hydrogenated NBR, EPDM (Ethylene-Propylene-Diene terpolymer) or the
like have been used as sealing materials, but these materials have
some defects such as swelling and blistering which occurs in the
sealing materials when contacting carbon dioxide. These undesirable
phenomena tend to cause the sealing device to be unusable.
Particularly, the addition of a non-reinforcing filler with a large
particle size such as mica or graphite for aiming to decrease in
gas permeability of these rubber materials makes blisters occur
easily, resulting in an unusable condition as a molded composition
for sealing carbon dioxide.
5. On the other hand, there are some materials having a property of
low gas permeability to carbon dioxide, such as vinylidene fluoride
resin or the like. But these materials have a defect in
processability or flexibility which rubber materials usually have.
When these resin like materials are used as sealing
materials--especially such a sealing means as a rotating shaft
seal, a reciprocating shaft seal or the like, response to an axis
to be sealed is slow when the axis is biased. This phenomena causes
a microscopical gap between the seal lip and the axis and then to
cause leakage of a sealing medium. In addition, when the sealing
material made of vinylidene fluoride resin is assembled with an
axis having splines (grooves made in the direction of the axis), a
scratch is easy to occur by the splines and the scratch may not
allow to keep optimum sealing performance.
6. There is a fluoro rubber which contains vinylidene fluoride.
This type of fluoro rubber has excellent flexibility but the
anti-permeability to carbon dioxide is not good.
7. Furthermore, it has been described in the publication of
Japanese patent Tokkai Sho 59-40066 (1984), Tokkai Hei 6-25500
(1994), Tokko Hei 3-2197 (1991), Tokko Hei 3-59937 (1991) and Tokko
Hei 7-68430 (1995) that a fluoro thermoplastic elastomer can be
used for a molding material for a sealing composition resistant to
lubricant. However, in these descriptions, MT carbon black
(particle diameter: 201 to 500 nm) which is commonly used as a
reinforcing filler for fluoro rubbers has been used as it is.
8. When fluoro thermoplastic elastomer containing MT carbon black
is used for sealing devices for sealing carbon dioxide, both
permeability of and swelling due to exposure to carbon dioxide is
large, and a blister phenomena can be seen so that these
compositions cannot be safely used in the seal for sealing carbon
dioxide.
SUMMARY OF THE INVENTION
9. An object of the present invention is to provide a molding
composition being composed of a fluoro rubber type thermoplastic
elastomer and a reinforcing filler, having an excellent anti-carbon
dioxide gas permeability and anti-swelling property to carbon
dioxide gas, and especially having an excellent anti-blistering
property to carbon dioxide gas.
10. Another object of the present invention is to provide a molded
sealing composition having excellent sealing properties to carbon
dioxide as well as having excellent rubber like responsive
properties.
11. Another object of the present invention is to provide a sealing
device having excellent sealing properties to carbon dioxide as
well as having excellent rubber like responsive properties to a
sliding portion to be sealed.
12. The object of the present invention can be achieved by using a
reinforcing filler with a particle size of 100 nm or smaller in a
fluoro thermoplastic elastomer, preferably by using the reinforcing
filler and a non-reinforcing filler in combination. Another object
of the present invention can be achieved by molding the fluoro
thermoplastic elastomer with or without other rubber materials into
various sealing products to seal carbon dioxide. Another object of
the present invention can be achieved by placing a fluoro
thermoplastic elastomer composition having reinforcing filler of
not larger than 100 nm in particle diameter onto a surface of
fluoro rubber sealing materials to form a sealing device.
BRIEF DESCRIPTION OF THE DRAWINGS
13. FIG. 1 shows a cross sectional view of a sealing device for
sealing carbon dioxide of the present invention.
14. FIG. 2 shows a cross sectional view of a metal ring, fluoro
rubber and fluoro thermoplastic elastomer composition that are
placed between an upper and a lower mold die. The die is then set
to press mold at a certain temperature and pressure to mold these
materials.
15. FIG. 3 shows a cross sectional view of a fluoro thermoplastic
elastomer composition that is to be formed into a sliding sealing
portion of the sealing device.
16. FIG. 4 shows a cross sectional view of the mold die and the
sealing device that has just been molded in the die.
17. FIG. 5 is a graph that shows relationships between volume ratio
of fluoro thermoplastic elastomer in the sealing device and
relative gas permeability.
DETAILED DESCRIPTION OF THE INVENTION
18. Fluoro thermoplastic elastomer is classified into two types,
namely, block type and graft type. In the present invention both of
the two types can be used; preferably, the block type is used.
19. The block type of fluoro thermoplastic elastomer is an ABA type
fluoro thermoplastic elastomer to be synthesized by radical
polymerization of fluoro monomers in chain transfer reaction
(telomerization) which is uniquely caused by iodine compound. The
block type fluoro thermoplastic elastomer is comprised of fluoro
rubber (soft segment) and fluoro resin (hard segment), which form
triblock copolymer. The soft segment and hard segment are
chemically bonded to each other in a single molecule. The block
type thermoplastic elastomer shows both rubbery and resinous
properties and can be molded without curing agent into a molded
product to have a rubbery elasticity.
20. Monomers composing the soft segment include vinylidene
fluoride, tetrafluoroethylene, hexafluoropropene or the like. For
examle a soft segment such as vinylidene
fluoride-hexafluoropropene-tetrafluoroethylene terpolymer is
composed of these monomers. On the other hand, monomers composing
the hard segment include vinylidene fluoride, ethylene,
tetrafluoroethylene or the like. For example, a hard segment such
as polyvinylidenefluoride segment or tetrafluoroethylene-ethylene
copolymer segment are provided from those monomers.
21. Reinforcing fillers such as carbon black or silica, preferably
carbon black, having a particle diameter of not larger than 100 nm
are added into these fluoro thermoplastic elastomers. Examples of
the carbon black having a particle diameter of not more than 100 nm
are SAF (particle size 11-19 nm), ISAF (particle size: 20-25 nm),
HAF (particle size: 26-30 nm), XCF (particle size: 31-39 nm), FEF
(particle size: 40-48 nm), GPF (particle size: 49-60 nm), and SRF
(particle size: 61-100 nm). When using reinforcing filler having a
particle diameter of larger than 100 nm, the reinforcing effect of
the particle is insufficient to cause blisters in molded articles.
In the thermoplastic elastomer, about 5 to 100 parts per hundred
rubber (phr), preferably about 10 to 70 phr of these reinforcing
fillers to 100 phr of thermoplastic elastomer is used. When the
amount of fillers is used in an amount of more than the above
mentioned phr range, there arises a difficulty in blending
elastomer with the filler. On the other hand, when the amount of
fillers is less than the above mentioned phr range, there arise
blisters in cured articles.
22. Examples of non-reinforcing fillers which are used together
with the reinforcing filler mentioned above are calcium
metasilicate, diatomite, graphite, mica, calcium carbonate, zinc
oxide or the like. About 5 to 100 phr, preferably about 5 to 60 phr
of one or more kinds of non-reinforcing fillers to 100 phr of
thermoplastic elastomer can be used in the compound. And the
combined amount of both reinforcing and non-reinforcing fillers are
in the range of about 10 to 200, preferably about 10 to 100 phr to
the 100 parts of the elastomer.
23. These non-reinforcing fillers are preferably used after surface
treatment with silane coupling agents or the like before using in
order to obtain wetability between thermoplastic elastomer and
non-reinforcing fillers. The average particle diameter of
non-reinforcing filler is not limited specifically. Powder type
non-reinforcing fillers can be used generally.
24. Organic peroxide is added into the aforementioned composition
as a curative. Organic peroxides are exemplified by
1,1-bis(tertiary butyl peroxy)-3,3,5-trimethylcyclohexane,
2,5-dimethylhexane-2,5-dihydroperoxid- e, di-tertiary butyl
peroxide, tertiary butyl cumyl peroxide, dicumyl peroxide,
.alpha.,.alpha.-bis(tertiary butyl peroxy)-p-diisopropyl benzene,
2,5-dimethyl -2, 5-di(tertiary butyl peroxy)hexane,
2,5-dimethyl-2,5-di(tertiary butyl peroxy)hexine-3, benzoyl
peroxide, tertiary butyl peroxy benzene,
2,5-dimethyl-2,5-di(benzoyl peroxy)hexane or the like. About 0.1 to
20 phr, preferably about 0.5 to 10 phr, of organic peroxides to 100
phr of thermoplastic elastomer is used in the molding
composition.
25. Besides these essential ingredients in this present invention
mentioned above, typical polyfunctional unsaturated crosslinking
agents such as triallylisocyanurate or the like and other various
additives can be added into this molding composition.
26. In order to decrease the viscosity of the molding composition,
about 5 to 60 phr, preferably about 5 to 40 phr of organic solvents
can be added into the composition to 100 phr of thermoplastic
elastomer. Examples of the organic solvent are aromatic or
aliphatic hydrocarbons such as toluene, xylene, n-hexane or the
like, esters of carboxylic acid such as ethyl acetate or the like,
ketones such as acetone, methylethyl ketone, methyl isobutyl ketone
or the like, alcohols such as methanol, ethanol or the like, ethers
such as tetrahydrofuran or the like, non-protonic polar solvents
such as dimethyl acetamide and dimethyl formamide. At least one of
the above mentioned organic solvents or a mixture of these solvents
or a mixture of these organic solvents with water is usefully added
into the composition of the present invention.
27. The molding composition can be prepared first by mixing all
ingredients except curatives in a kneader, and after the thus
obtained mixed compound is further kneaded on a heating roll,
curatives are added into the mixed compound thereafter. The molding
composition of the present invention can be also obtained by using
a twin screw extruder to mix the elastomer with fillers and
additives which are supplied through a feeder set halfway of the
screw. It is also possible to use the combination of a twin screw
extruder where all ingredients except curatives are mixed and one
screw extruder where curatives are added. In this case the
composition containing curatives can be extruded through T die to
form a sheet like molding composition. Moreover, it is more
desirable to eliminate air or volatile materials contained in the
mixed composition using a vent type extruder for preventing
blisters.
28. The molding composition prepared above is molded by press
molding, injection molding or the like to form a molded sealing
composition at the temperature of about 150 to 220.degree. C., at
the pressure of about 100 to 1500 Kgf/cm2, and for about 1 to 20
minutes and then followed by an oven vulcanizing process (secondary
vulcanization or secondary cure) at the temperature of about 180 to
230.degree. C. for about 1 to 24 hours.
29. The molded sealing composition for sealing carbon dioxide of
the present invention can be effectively used as a portion of a
sealing device to seal carbon dioxide between relatively movable
portions, on one of which the sealing device is mounted and
slidably engaging with another relatively movable portion at a seal
lip of the sealing device. Oil seals or the like are examples of
these sealing devices.
30. FIG. 1 shows a cross sectional view of a sealing device which
is formed by using the molded sealing composition of the present
invention. Wherein, the sealing device 1 is comprised of a sealing
potion of a lip or the like being integrally formed on a metal ring
2, and an outer sealing portion 3 which is mounted on an inner
periphery of a housing 4. In an inner peripheral side of the
sealing device, an edge portion of slidable sealing portion 5 and 6
is pressed toward an axis 9 via a spring holder 8 by a garter
spring 7 to cause sealing contact with the axis. In this
construction, a dust lip may be installed to prevent foreign
material such as dust or the like to enter into the carbon dioxide
side from the air side, if necessary.
31. The sealing portion 5 is made of the fluoro thermoplastic
elasotmer composition, and the sealing portion 6 is made of a
fluoro rubber composition and a part of the sealing portion is
covered by the fluoro thermoplastic elastomer composition as is
shown in FIG. 1. The sealing device having the sealing portions 5
and 6 can be manufactured by using a mold die as is shown in FIG.
2, 3 and 4.
32. As is shown in FIG. 2, 3 and 4, a molding die is composed of a
lower die 10, 11 which is used for forming an air side portion of
the sealing device and an upper die 12 which is used for forming a
carbon dioxide side portion. Fluoro rubber composition 13 is placed
in the lower die as shown in FIG. 2, then as shown in FIG. 3
pre-shaped fluoro thermoplastic elastomer composition 14 is placed
together with a metal ring 15, and then the upper die 12 is placed
to compression-mold. At this time it is desirable that the
temperature of these dies are heated up to melting temperature of
the fluoro thermplastic elastomer 14. Fluoro rubber composition 13
and fluoro thermoplastic elastomer composition 14 are, by flowing
into the back of the metal case 15, formed into sliding portions 5
and 6 of the sealing portion as shown in FIG. 1.
33. As for the fluoro rubber composition which is formed into the
sealing sliding portion 6, vinylidene fluoride copolymer such as
vinylidene fluoride-hexafluoropropen copolymer, vinylidene
fluoride-pentafluoroprope- n copolymer, vinylidene
fluoride-chlorotrifluoroethylene copolymer, vinylidene
fluoride-hexafluoropropen-tetrafluoroethylene terpolymer,
vinylidene fluoride-pentafluoropropen-tetrafluoroethylene
terpolymer, vinylidene fluoride-perfluoro(methyl vinyl
ether)-tetrafluoroethylene terpolymer or the like can be used, and
it is more desirable that at least one kind of monomer used in the
fluoro rubber is also used as the monomer in the fluoro
thermoplastic elastomer for reasons to be mentioned below. Viton B
or the like, for example, which is a fluoro rubber manufactured by
Du Pont de Numerous & Co. can be used as a rubber ingredient in
a fluoro rubber composition.
34. Similar kinds of compounding ingredients which are used in the
fluoro thermoplastic elastomer composition can be used in these
fluoro rubber compositions, and polyol type curatives or polyamine
type curatives can be used, but peroxide type curatives can be
preferably used. It is also desirable that the fluoro rubber and
fluoro thermoplastic elastomer are cured by the same curing agent,
but different curing agents can also be used for each rubber and
elastomer according to the purpose or the environment of use of the
product.
35. The sliding sealing portion 5 is made of the fluoro
thermoplastic elastomer composition. There are two kinds of fluoro
thermoplastic elastomers, block type and graft type. In the present
invention any of the two kinds of fluoro thermoplastic elastomers
can be used, but block type elastomer is more preferably used.
36. The composition of fluoro rubber and fluoro thermoplastic
elastomer are molded by compression molding, injection molding or
the like at the temperature of about 150 to 220.degree. C. at the
pressure of about 100 to 1500 Kgf/cm.sup.2, for about 1 to 20
minutes and then oven cured (secondary cure) at the temperature of
about 180 to 230.degree. C., for about 1 to 24 hours. The fluoro
thermoplastic elastomer composition is used in the range of about
0.1 to 0.9 volume ratio, preferably about 0.3 to 0.7, in the
combined amount of the fluoro rubber composition and the fluoro
thermoplastic elastomer composition of the sealing device.
37. It is necessary that a portion of the surface of the sealing
device that directly contacts with carbon dioxide is at least made
of fluoro thermoplastic elastomer composition. If the surface which
directly contacts with carbon dioxide is all covered with the
fluoro thermoplastic elastomer composition, the volume of the
fluoro thermoplastic elastomer composition in the sealing device is
based upon the ratio of the thickness of the sliding portion 5 in
FIG. 5 and the carbon dioxide permeability across the sealing
device can be more effectively decreased.
38. Fluoro rubber and fluoro thermoplastic elastomer are
crosslinked respectively in each composition, and at the same time
in the interface of each composition, the same kind of monomer
segments of both rubber and elastomer tend to agglomerate and
simultaneously to be cross-linked with each other by chemical
reaction to cause a strong bond in the interface between rubber and
elastomer without using any adhesives.
39. The crystalline segment of the copolymer (hard segment) in
fluoro thermoplastic elastomer has a melting temperature. Above the
melting temperature, the crystalline segment will melt and the
molecular chain in the segments becomes highly movable. Under these
conditions agglomeration of the same kind of segments in the
polymer occurs easily, so that the molding temperature of each
material used must be carefully set to obtain maximum effect of
agglomeration.
40. Fluoro thermoplastic elastomer, when compared to vinylidene
fluoride resin, has a rather elastic property similar to fluoro
rubber. So the sliding sealing portion which is made of both fluoro
rubber and fluoro thermoplastic elastomer has an excellent property
with respect to the portion to be sealed.
EFFECT OF THE INVENTION
41. The molding composition of the present invention shows
excellent properties in anti-permeability to carbon dioxide gas and
in resistance of swelling and blistering when contacting carbon
dioxide. Therefore, the molding composition can be effectively used
for molding sealing articles (lip seal, packing, gasket, O-ring, or
the like) , hoses, tubes, diaphragms, or the like which contact
with carbon dioxide.
42. According to the present invention, fluoro rubber and fluoro
thermoplastic elastomer which preferably contain at least one
common copolymer component in both rubber and thermoplastic
elastomer are combined to form a sliding sealing portion of a
sealing device for sealing carbon dioxide so that excellent bonding
strength can be obtained between the interface of both rubber and
thermoplastic elastomer without using any adhesives. There is no
need to use adhesives between an interface of both rubber and
thermoplastic elastomer. And as a result not only the cost of the
adhesion process can be eliminated but also high durability in
sliding sealing portion can be attained.
43. On the other hand, by using fluoro thermoplastic elastomer in
the sliding sealing portion, rubbery elasticity that has not been
attained when fluoro resin has been used can be secured. And an
excellent property in decreasing permeation of carbon dioxide gas
across the sealing device is also attained and also an excellent
property in responding to the portion to be sealed is attained.
44. Moreover, by varying volume ratio of fluoro rubber to fluoro
thermoplastic elastomer, a sealing device having a desired carbon
dioxide permeability can be obtained.
45. The invention is shown in more detail in the following examples
and these embodiments should not be interpreted as limiting the
scope of the present invention.
EXAMPLE
Example 1
46.
1 Fluoro thermoplastic elastomer 100 phr (Daikin product
Daiel-Thermo T-630) FEF carbon black 35 phr Magnesium oxide 5 phr
Organic peroxide 1.5 phr (Nippon Yusi product Percumyl D) Triallyl
isocyanurate 3 phr (Nihon Kasei product Taic M60, 60%)
47. Ingredients except for an organic peroxide were mixed using a
3L kneader and further kneaded on a heating roll (80.degree. C.),
and finally the organic peroxide was mixed. The thus obtained
thermoplastic elastomer composition was press vulcanized at the
temperature of 195.degree. C. for 8 minutes and then oven cured
(secondary vulcanization) at 200.degree. C. for 15 hours to make
two discoid sheets with a diameter of 90 mm and thickness of 0.5
mm. One of these sheets was assigned to a discoid sample with a
diameter of 50 mm and the other was punched to make a squared
sample with a size of 30.times.30 mm.
48. The discoid sample was used for measuring carbon dioxide
permeability (cm.sup.3.multidot.mm/m.sup.2.multidot.atm.multidot.24
hours) under the condition of 5 kgf/cm.sup.2 by using a gas
permeability gauge of Gasperm 100 (Nihon Bunko Kogyo product). The
squared sample was used for measuring the change of weight (weight
swelling ratio, weight %) of the sample by putting the sample in a
pressure-proof container with an inner volume of 50 ml, injecting
carbon dioxide gas into the pressure-proof container, and finally
letting it stand in the conditions of 100.degree. C., 80
kgf/cm.sup.2, for 2 hours followed by returning to room temperature
and atomospheric pressure, together with the number of blisters
(number/cm.sup.2) occurred on the surface of the sample.
Example 2
49. In Example 1, ten (10) phr of FEF carbon black was used instead
of 35 phr of FEF carbon black, and 30 phr of acetone and 10 phr of
methanol were further added.
Example 3
50. In Example 2, same amount of silica (Aerosil Co. product, A200)
was used instead of FEF carbon black.
Comparative Example 1
51. In Example 1, FEF carbon black was not used.
Comparative Example 2
52. In Example 1, same amount of MT carbon black was used instead
of FEF carbon black.
Comparative Example 3
53.
2 Hydrogenated NBR 100 phr (Nippon Zeon product, Zetpol 2010) FEF
carbon black 35 phr Zinc oxide 5 phr Organic peroxide 8 phr (Nihon
Yusi product, Peroximon F40) Stearic acid 0.5 phr
54. Mixing, vulcanization (press cure was done at 180.degree. C.,
for 4 minutes; secondary cure was done at 165.degree. C., for 30
minutes) and measurement were carried out by the same method as in
Example 1.
Comparative Example 4
55.
3 Fluro rubber (Du Pont product, Viton B) 100 phr FEF carbon black
35 phr Magnesium oxide 5 phr N,N'-dicinnamylidene-1,6-hexane
diamine 3 phr
56. Mixing, vulcanization (press cure was done at 205.degree. C.,
for 4 minutes; secondary cure was at 215.degree. C. , for 2 hours),
and measurement were carried out by the same methods as in Example
1.
Example 4
57. In Example 1, fifteen (15) phr of SRF carbon black and 20 phr
of silica (Aerosil Co. product, A200) were used instead of FEF
carbon black.
Example 5
58. In Example 1, ten (10) phr of HAF and 20 phr of calcium
metasilicate (Tomoe Kogyo product, NYAD1250) were used instead of
FEF carbon black.
Example 6
59. In Example 1, seven (7) phr of ISAF and 25 phr of graphite
(Nichiden Carbon product, Graphite AO) were used instead of FEF
carbon black. And the amounts of organic peroxide and
triallylisocyanurate were changed to 1 and 3.5 phr,
respectively.
Example 7
60. In Example 1, ten (10) phr of ISAF carbon black and 35 phr of
mica (Yamaguchi Mica Kogyosho product, Mica Powder A21A) were used
instead of FEF carbon black. And the amounts of organic peroxide
and triallylisocyanurate were changed to 1 and 3.5 phr,
respectively.
Example 8
61. In Example 7, same amount of silica (Aerosil A200) was used
instead of ISAF carbon black.
Comparative example 5
62. In Example 7, same amount of MT carbon black was used instead
of ISAF carbon black.
Example 9
63. In Example 7, twenty (20) phr of calcium metasilicate (Tomoe
Kogyo product, Wollascoat) was used instead of 35 phr of mica.
Comparative example 6
64.
4 Hydrogenated NBR 100 phr (Nippon Zeon product, Zetpol 1010) FEF
carbon black 10 phr Magnesium oxide 5 phr Acetone 30 phr Methanol
10 phr Organic peroxide (Percumyl D) 1.5 phr Triallylisocyanurate 3
phr (Nihon Kasei product, Taic M60, 60%)
65. Mixing, vulcanization, and measurement were carried out by the
same method as Comparative Example 3.
66. The results of the measurement of both examples and comparative
examples are shown in Table 1.
5TABLE 1 Example or Permeability Comparative of carbon Weight
swelling The number of Example dioxide ratio blisters Example 1 380
0.25 0 Example 2 400 -- 0 Example 3 420 -- 0 Comparative 970 0.60 8
Example 1 Comparative 410 0.30 6 Example 2 Comparative 1750 0.29 10
Example 3 Comparative 570 2.50 13 Example 4 Example 4 379 0.24 0
Example 5 375 0.25 0 Example 6 379 0.26 0 Example 7 370 0.25 0
Example 8 382 0.23 0 Comparative 405 0.31 9 Example 5 Example 9 379
0.26 0 Comparative 1350 -- 10 Example 6
Reference Example 1 (Example 10)
67.
6 Fluoro thermoplastic elastomer 100 phr (Daikin product:
Daiel-Thermo T-630) FEF carbon black 10 phr Graphite 5 phr Calcium
metasilicate 20 phr Stearic acid 1 phr Magnesium oxide 6 phr
Organic peroxide (Percumyl D) 1.4 phr Triallyl isocyanurate 1
phr
68. Ingredients except for the organic peroxide were mixed by using
a 3L kneader, further kneaded using a heat roll (80.degree. C.),
and finally the organic peroxide was added. This composition was
press vulcanized at 195.degree. C., at 100 kgf/cm2, and for 4
minutes and then oven vulcanized ( secondary cure ) at 200.degree.
C. for 6 hours to obtain vulcanized sheets having a thickness of 2
mm.
69. The thus obtained sheet was tested for gas permeability by
using a gas permeability measurement device of Gasperm 100 type
(Nihon Bunko Kogyo product) under the condition of room
temperature, at 5 kgf/cm.sup.2, and 60 minutes (N.sub.2, O.sub.2)
or 30 minutes (CO.sub.2).
Reference Example 2 (Example 11)
70. In Reference Example 1, same amount silica (Aerosil A200) was
used instead of FEF carbon black.
Reference Example 3 (Example 12)
71. In Reference Example 1, Graphite and calcium metasilicate which
are non-reinforcing fillers were not used and 55 phr of FEF carbon
black was used instead of 10 phr of FEF carbon black.
Reference Example 4 (Comparative Example 7)
72. In Reference Example 1, same amount of hydrogenated NBR (Zetpol
1010 ) was used instead of fluoro thermoplastic elastomer. This
composition was press vulcanized at the temperature of 180.degree.
C., at the pressure of 100 kgf/cm2, and for 8 minutes and then oven
cured ( secondary cure ) at 150.degree. C. for 1 hour to obtain
vulcanized sheets having a thickness of 2 mm.
73. Permeability (
cm.sup.3.multidot.mm/m.sup.2.multidot.atm.multidot.24 hours) to
various gases measured on aforementioned Reference Examples are
shown in Table 2.
7TABLE 2 Reference Reference Reference Reference Gas Example 1
Example 2 Example 3 Example 4 Nitrogen 20 5 25 20 gas Oxygen gas 60
55 115 70 Carbon 381 390 423 1320 dioxide gas
74. As is shown in Table 2, hydrogenated NBR composition shows an
excellent performance as a gas barrier material to nitrogen and
oxygen gases, however, poor gas barrier performance to carbon
dioxide was shown. On the other hand, the compositions of the
present invention show excellent properties in anti-gas
permeability to carbon dioxide.
75. Next, a sealing device will be explained below.
76. Composition A
8 Fluoro rubber (Du Pont product, Viton B) 100 phr MT carbon black
15 phr Calcium oxide 15 phr Magnesium oxide 15 phr Organic peroxide
(Percumyl D) 1.5 phr Triallyl isocyanurate 3 phr (Nihon Yusi ,Taic
M60, 60%,)
77. All ingredients in the above recipe were mixed and further
kneaded as the same condition as described in Example 1. Then the
compound obtained was press cured at 190.degree. C., for 8 minutes,
and then oven cured in an oven ( secondary cure ) at 200.degree.
C., for 13 hours. Measurement of gas permeability of the thus
obtained sample was carried out using the same procedures as
described in Example 1.
Reference example 6 (Composition B)
78.
9 Fluoro rubber (Du Pont product, Viton B) 100 phr FEF carbon black
35 phr Calcium oxide 5 phr N,N'-dicinnamylidene-1,6-hexanediamine 3
phr
79. All ingredients in the above recipe were mixed and further
kneaded as the same condition described in Example 1. Then the
composition obtained was press cured at 205.degree. C., for 4
minutes, and then oven cured in an oven (secondary cure) at
215.degree. C., for 22 hours. Measurement of gas permeability of
the thus obtained sample was carried out using the same procedures
as described in Example 1.
80. Results of the measurements of permeability of carbon dioxide
gas are shown in Table 3.
10 TABLE 3 Permeability of carbon Example or Composition dioxide
Example 1 380 Example 4 379 Composition A 580 Composition B 570
Example 13
81. In sealing device shown in FIG. 1, the sliding sealing portion
5 was made of the same composition as described in Example 1 and
the sliding sealing portion 6 was made of the same composition as
described in Composition A.
Example 14
82. In the sealing device shown in FIG. 1, the sliding sealing
portion 5 was made of the same composition as described in Example
4 and the sliding sealing portion 6 was made of the same
composition as described in Composition A.
Example 15
83. In the sealing device shown in FIG. 1, the sliding sealing
portion 5 was made of the same composition as described in Example
1 and the sliding sealing portion 6 was made of the same
composition as described in Composition B.
Example 16
84. In the sealing device shown in FIG. 1, the sliding sealing
portion 5 was made of the same composition as described in Example
4 and the sliding sealing portion 6 was made of the same
composition as described in Composition B. Comparative Example
7
85. In the sealing device shown in FIG. 1, the sliding sealing
portions 5 and 6 were made of the same composition as described in
Composition A.
Comparative Example 8
86. In the sealing device shown in FIG. 1, the sliding sealing
portions 5 and 6 were made of the same composition as described in
Composition B.
87. Sealing device (inner diameter of the sliding sealing portion:
13 mm, outer diameter of the sealing device: 30 mm) in the above
Examples (13, 14, 15 and 16 ) and Comparative examples (7, 8 ) were
made by press molding at 185.degree. C., for 10 minutes, and then
oven cured at 165.degree. C., for 10 hours. The thickness of the
surface in the sliding sealing portion 5 was 1 mm, and the
thickness of the sliding sealing portion 6 was 12 mm. Sealing
properties of these sealing devices were evaluated under the
condition that the diameter of the shaft which slidably and
sealingly contacts with the sliding sealing portion of the sealing
device was 15 mm, the revolution of the shaft was 2000 rpm, sealing
oil which was used for lubrication to the sliding sealing portion
was SAE30W, test temperature was 100.degree. C. More detailed test
conditions were as follows.
88. The carbon dioxide side of the sealing device was set to keep
airtight conditions. This airtight room was at first filled with
carbon dioxide gas at a pressure of 5 Kgf/cm.sup.2 and the change
of the pressure decrease in the room was measured during the test
operation. Carbon dioxide gas permeability of the sealing device
made of only fluoro rubber composition was set to 1, and then the
permeability of the Examples were measured, and relative
permeabilities were then calculated.
89. Gas permeability coefficient, Pc, of the sealing device having
a laminated seal lip portion made of both fluoro rubber and fluoro
thermoplastic elastomer (TPE) compositions as shown in FIG. 1 was
theoretically calculated by the following equation.
90. 1/Pc=.phi..sub.rubber/P.sub.rubber+.phi..sub.TPE/P.sub.TPE
91. P.sub.rubber: Gas permeability of fluoro rubber
92. P.sub.TPE: Gas permeability of TPE
93. .phi..sub.rubber: Volume ratio of fluoro rubber
94. P.sub.rubber: Volume ratio of TPE
95. The results obtained were shown in FIG. 5 and the theoretical
curve calculated by the above equation was also shown as well in
FIG. 5.
* * * * *