JP2004210813A - Hose material for fuel battery and hose for fuel battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose material for a fuel battery, having both characteristics of low extractability and electric insulation property. <P>SOLUTION: The hose material for the fuel battery is obtained by compounding an olefinic resin as an organic filler with an ethylene-propylene-diene terpolymer. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３８】
【表２】

【００３９】
上記結果より、実施例品は、いずれも、硬度が高く、圧縮永久歪み特性、電気絶縁性、低抽出性の全ての特性に優れていることがわかる。実施例５品は、トルエン着色透過度が従来よりも高め、すなわち未燃分量の少ないクリーンなカーボンブラックを用いているため、低抽出性がさらに向上することがわかる。
【００４０】
これに対して、比較例１品は、エチレン−オレフィン系樹脂を有機フィラーとして配合していないため、伸びが低下し、低硬度で、電気絶縁性に劣ることがわかる。比較例２品は、カーボンブラックを高充填しているため、高硬度ではあるが、伸び、電気絶縁性が悪くなることがわかる。比較例３品は、カーボンブラックとシリカを併用しているため、電気絶縁性は優れているが、低抽出性が著しく劣ることがわかる。比較例４品は、ポリエチレン樹脂をフィラーとして配合しているが、ポリエチレン樹脂の結晶性が高いため、圧縮永久歪み特性に劣ることがわかる。
【００４１】
【発明の効果】
以上のように、本発明の燃料電池用ホース材料は、エチレン−プロピレン−ジエン三元共重合体（ＥＰＤＭ）に、エチレン−オレフィン系樹脂を有機フィラーとして配合してなるものである。このように、本発明は、エチレン−オレフィン系樹脂をポリマーとして用いるのではなく、有機フィラーとして、ＥＰＤＭ中に配合しているため、電気絶縁性に優れるとともに、シリカ等の無機フィラーを用いた場合のような、Ｓｉ元素やイオンの溶出等もないため、低抽出性にも優れている。また、有機フィラーとして用いたエチレン−オレフィン系樹脂が、ＥＰＤＭ中にいわば相溶したかのような状態で分散するため、ＥＰＤＭの機械的物性を損なうこともなく、両者の混練性にも優れている。また、エチレン−オレフィン系樹脂は、ポリエチレン樹脂等の通常の樹脂に比べて、結晶性が低く、エラストマーと樹脂との中間の結晶性を備え、エラストマーと樹脂の双方の特徴を併せ持つため、圧縮永久歪み特性も良好である。
【００４２】
また、エチレン−オレフィン系樹脂の配合割合を、特定の範囲に設定すると、低抽出性および電気絶縁性がさらに向上するようになる。
【図面の簡単な説明】
【図１】本発明の燃料電池用ホース材料における、エチレン−オレフィン系樹脂の分散状態を示す模式図である。
【符号の説明】
１ ＥＰＤＭ
２ エチレン−オレフィン系樹脂
３ カーボンブラック[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a fuel cell hose material and a fuel cell hose using the same, and more specifically, to a fuel cell hose material used for an aqueous hose of a fuel cell and a fuel cell using the same. It is related with the hose.
[0002]
[Prior art]
As a next-generation power generation method, a power generation method using a fuel cell system is considered promising. The power generation site in this fuel cell system is significantly degraded in performance due to external contaminants such as metal ions. Therefore, the fuel cell hose material used in the fuel cell system is also required to be clean with low extractability (property of being extracted by water or the like flowing through the hose). This fuel cell hose material is also required to have electrical insulation (high electrical resistance) from the viewpoint of preventing ignition due to static electricity sparks and preventing electric shock due to stray current and leakage from the fuel cell body. From the viewpoint of pressure resistance and noise countermeasures, it is also required to have high mechanical properties while having high hardness.
[0003]
As such a fuel cell hose material, a material in which carbon black is blended with an ethylene-propylene-diene terpolymer (EPDM) has been conventionally used (for example, see Patent Document 1). However, when a fuel cell hose is molded using this fuel cell hose material, there are disadvantages in that the mechanical properties are low and the electrical insulation is inferior. In this case, it is conceivable to increase the hardness by increasing the amount of carbon black to be blended with EPDM, that is, by making the carbon black highly filled.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-180941
[Problems to be solved by the invention]
However, when carbon black is highly filled and hardened as described above, the carbon black particles approach, so the electrical resistance is further lowered, the conductivity is further increased, and the electrical insulation is significantly inferior. is there. In addition, there is a problem that the elongation of the hose is lowered and the scorch is also deteriorated. Therefore, it is conceivable that carbon black and silica are used in combination without increasing the amount of carbon black, instead of highly filling carbon black. However, although this material is excellent in electrical insulation, there is a problem that low extractability is remarkably inferior due to elution of Si element in silica. Thus, it is the actual situation that a hose material for fuel cells that can achieve both low extractability and electrical insulation and has excellent mechanical properties has not yet been obtained. Development is awaited.
[0006]
The present invention has been made in view of such circumstances, and is a fuel cell hose material that is excellent in both low extractability and electrical insulation properties and excellent in mechanical properties, and a fuel cell using the same. The purpose is to provide a hose for use.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has as a first gist a fuel cell hose material obtained by blending an ethylene-propylene-diene terpolymer with an ethylene-olefin-based resin as an organic filler, A fuel cell hose formed into a hose shape using this fuel cell hose material is a second gist.
[0008]
In order to obtain a fuel cell hose that is excellent in both low extractability and electrical insulation properties and has excellent mechanical properties, the present inventors have conducted extensive research focusing on fuel cell hose materials. . In the course of that research, we focused on ethylene-olefin resins and not using them as polymers, but when blended in EPDM as organic fillers, they have excellent electrical insulation properties, and when inorganic fillers such as silica are used Since there is no elution of Si elements and ions, it has also been found that it has excellent low extractability. In addition, when this ethylene-olefin resin is used as an organic filler, the ethylene-olefin resin is dispersed in a state that is compatible with the EPDM, so that the mechanical properties of the EPDM are impaired. Nonetheless, both are excellent in kneadability. In addition, ethylene-olefin resins have lower crystallinity than ordinary resins such as polyethylene resins, have intermediate crystallinity between elastomers and resins, and have characteristics of both elastomers and resins. -When an olefin resin is used as the organic filler, compression set characteristics are also improved.
[0009]
At the beginning of the research, we focused on the polyethylene resin and conducted an experiment using it as an organic filler, not as a polymer. However, since polyethylene resin has high crystallinity, it has the disadvantage that the compression set characteristics deteriorate. occured. Such a deterioration in compression set characteristics means that a hose made of the above material does not recover as it is when clipped and tightened. This is fatal when used for hoses.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail.
[0011]
The fuel cell hose material of the present invention is used by blending ethylene-propylene-diene terpolymer (EPDM) with an ethylene-olefin resin as an organic filler.
[0012]
The ethylene-propylene-diene terpolymer (EPDM) is not particularly limited, but preferably has an iodine value of 6 to 30 and an ethylene ratio of 48 to 70% by weight. Has an iodine value in the range of 10 to 24 and an ethylene ratio in the range of 50 to 60% by weight. Such EPDM is excellent in stability at high temperature and pressure. An ethylene-propylene copolymer (EPM) can also be used.
[0013]
The diene monomer (third component) contained in this EPDM is not particularly limited, but is preferably a diene monomer having 5 to 20 carbon atoms, specifically 1,4-pentadiene, 1,4-hexadiene. 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), 5-butylidene-2-norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and the like. Among these diene monomers (third component), dicyclopentadiene (DCP) and 5-ethylidene-2-norbornene (ENB) are preferable.
[0014]
In the present invention, the greatest feature is to use ethylene-olefin resin as an organic filler together with EPDM. The ethylene-olefin resin is not particularly limited, and examples thereof include those obtained by copolymerizing ethylene and an α-olefin having 3 to 10 carbon atoms. Examples of the α-olefin having 3 to 10 carbon atoms include propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, nonene-1, and decene-. 1 etc. These may be used alone or in combination of two or more. Especially, as said ethylene-olefin type-resin, what copolymerized ethylene and C6-C10 alpha-olefin is preferable since it is excellent in the balance of mechanical strength and radical crosslinkability, Especially preferably, , An ethylene-octene resin obtained by copolymerizing ethylene and octene-1.
[0015]
The ethylene-olefin resin used in the present invention can be produced by a known metallocene catalyst. This metallocene-based catalyst is composed of a cyclopentadienyl derivative of a group IV metal such as titanium or zirconium and a co-catalyst, and is not only highly active as a polymerization catalyst but also a conventional catalyst such as a Ziegler Compared with the system catalyst, the molecular weight distribution of the copolymer obtained is narrow, the distribution of the α-olefin having 3 to 10 carbon atoms as the comonomer in the copolymer is uniform, and the catalyst species is uniform. It is a feature.
[0016]
Compared to the case of using a Ziegler catalyst or the like, an ethylene-olefin resin using a metallocene catalyst has a super-high polymerization catalyst, so the composition of the comonomer α-olefin is greatly increased compared to the conventional case. It is possible to obtain an elastomeric copolymer excellent in flexibility even in a state in which no plasticizer is contained.
[0017]
The blending ratio of the ethylene-olefin-based resin is preferably in the range of 2 to 40 parts, particularly preferably in the range of 5 to 20 parts, with respect to 100 parts by weight of EPDM (hereinafter abbreviated as “parts”). That is, when the blending ratio of the ethylene-olefin resin is less than 2 parts, effects such as high electrical resistance and low extractability tend to be inferior, and conversely, when it exceeds 40 parts, the hose is like shark skin. This is because the hose appearance deteriorates and the roll processability tends to deteriorate.
[0018]
The fuel cell hose material of the present invention includes an ethylene-propylene-diene terpolymer and an ethylene-olefin resin, as well as carbon black, a peroxide cross-linking agent, a co-crosslinking agent, a process oil, an anti-aging agent, etc. May be blended as necessary.
[0019]
The carbon black is not particularly limited as long as it has excellent extrudability and excellent reinforcement, and examples thereof include SRF grade carbon black. In particular, carbon black designed to have a high electrical resistance generally has a large amount of unburned components and tends to have a low toluene coloring transmittance of 20%. By using about -50% carbon black, the low electrical extractability is further improved while maintaining high electrical resistance.
[0020]
The blending ratio of this carbon black is preferably in the range of 20 to 140 parts, particularly preferably in the range of 60 to 120 parts, with respect to 100 parts of EPDM. That is, if the carbon black is less than 20 parts, the reinforcing effect is poor, and it is difficult to increase the hardness. Conversely, if it exceeds 140 parts, the electrical resistance tends to be low and the electrical insulation tends to be poor. Because.
[0021]
Examples of the peroxide crosslinking agent include 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -3,3, 5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1-bis (t-butylperoxy) cyclohexane, 2, Pers such as 2-bis (t-butylperoxy) octane, n-butyl-4,4-bis (t-butylperoxy) butane, n-butyl-4,4-bis (t-butylperoxy) valerate, etc. Oxyketals, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, α, α'-bis (t-butylperoxy-m-iso Propyl) benzene, α, α′-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis Dialkyl peroxides such as (t-butylperoxy) hexyne-3, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl Diacyl peroxides such as peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, m-trioyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxide Oxy-2-ethylhexanoate , T-butyl peroxylaurate, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butyl peroxymalein Peroxyesters such as acid, t-butylperoxyisopropyl carbonate, cumylperoxyoctate, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2, And hydroperoxides such as 5-dihydroperoxide and 1,1,3,3, -tetramethylbutyl peroxide. These may be used alone or in combination of two or more. Among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is preferably used in that there is no problem of odor.
[0022]
The proportion of the peroxide crosslinking agent is preferably in the range of 1.5 to 20 parts with respect to 100 parts of EPDM. That is, when the peroxide cross-linking agent is less than 1.5 parts, the cross-linking is insufficient and the hose strength is inferior. Conversely, when the peroxide cross-linking agent exceeds 20 parts, it becomes too hard and the hose is flexible. This is because the tendency to be inferior is seen.
[0023]
Further, as the co-crosslinking agent, for example, divinylbenzene and triallyl isocyanurate (TAIC) are preferably used. Together with these, triallyl cyanurate, diacetone diacrylamide, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, Methylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diisopropenylbenzene, p-quinonedioxime, p, p-dibenzoylquinonedioxime, phenylmaleimide, Allyl methacrylate, N, N-m-phenylenebismaleimide, diallyl phthalate, tetraallyloxyethane, 1, - polybutadiene and the like. These may be used alone or in combination of two or more.
[0024]
The proportion of the co-crosslinking agent is preferably in the range of 0.1 to 10 parts, particularly preferably in the range of 0.5 to 7.0 parts, with respect to 100 parts of EPDM.
[0025]
The blending ratio of the process oil is preferably in the range of 5 to 100 parts, particularly preferably in the range of 20 to 80 parts, with respect to 100 parts of EPDM.
[0026]
Examples of the antiaging agent include carbamate type antiaging agent, phenylenediamine type antiaging agent, phenol type antiaging agent, diphenylamine type antiaging agent, quinoline type antiaging agent, and waxes. These may be used alone or in combination of two or more.
[0027]
The blending ratio of this anti-aging agent is preferably in the range of 0.2 to 2 parts, particularly preferably in the range of 0.5 to 1.0 part, with respect to 100 parts of EPDM.
[0028]
The hose material for a fuel cell of the present invention includes, for example, an ethylene-propylene-diene terpolymer (EPDM) blended with an ethylene-olefin resin as an organic filler, and, if necessary, carbon black, peroxide. It can be prepared by blending a product cross-linking agent, a co-crosslinking agent, a process oil, an anti-aging agent and the like and kneading them using a kneader such as a kneader, a Banbury mixer, or a roll.
[0029]
In the fuel cell hose material of the present invention thus obtained, for example, as shown in FIG. 1, the ethylene-olefin resin 2 is in a state in which its interface is in a so-called compatible state in EPDM1. Since it is dispersed as an organic filler, it does not impair the mechanical properties of EPDM1 and is excellent in kneadability between them. In the figure, 3 indicates carbon black.
[0030]
The fuel cell hose of the present invention is, for example, extruded from the fuel cell hose material of the present invention prepared as described above, and then vulcanized in its entirety under a predetermined condition using a mandrel. It can be produced by pulling it out of the mandrel.
[0031]
The fuel cell hose of the present invention thus obtained has a thickness usually in the range of 1.5 to 12 mm, and an inner diameter of usually 5 to 50 mm.
[0032]
The fuel cell hose of the present invention is not limited to the single layer structure as described above, and may have a multilayer structure of two or more layers. In this case, the innermost layer of the fuel cell hose of the present invention is preferably formed using the fuel cell hose material of the present invention from the viewpoint of low extractability and electrical insulation.
[0033]
Next, examples will be described together with comparative examples.
[0034]
First, prior to the examples and comparative examples, the following materials were prepared.
[EPDM]
Manufactured by Sumitomo Chemical Co., Ltd., Esprene 501A [iodine value: 12, ethylene ratio: 50 wt%, Mooney viscosity (ML1 + 4 100 ° C.): 43]
[Ethylene-octene resin]
DACT PLASTOMERS, EXACT 0210
[Carbon black (1)]
SRF grade carbon black (Showa Cabot Corporation, Show Black IP-200, Toluene color transmission: 20%)
[Carbon black (2)]
SRF grade carbon black (Asahi Carbon Co., Ltd., Asahi # 52, Toluene color transmission: 40%)
[Process oil]
Idemitsu Kosan Co., Ltd., Diana Process PW-380
[Peroxide crosslinking agent]
2,5-dimethyl-2,5-di (t-butylperoxy) hexane (manufactured by NOF Corporation, Perhexa 25B)
[Co-crosslinking agent]
Ethylene glycol dimethacrylate (Seiko Chemical Co., Ltd., High Cloth ED)
[Phenylamine anti-aging agent]
N-phenyl-N'-isopropyl-p-phenylenediamine (manufactured by Seiko Chemical Co., Ltd., Ozonon 3C)
〔silica〕
NIPSEAL ER, manufactured by Nippon Silica Industry
[Polyethylene resin]
Asahi Kasei Kogyo Co., Ltd., Suntec LD M6545
[0035]
Examples 1-5, Comparative Examples 1-4
The components shown in Table 1 and Table 2 below were blended in the proportions shown in the same table, and kneaded using a Banbury mixer and roll to prepare a fuel cell hose material.
[0036]
Using the fuel cell hose materials of the example product and the comparative product obtained in this way, each characteristic was evaluated according to the following criteria. These results are shown in Tables 1 and 2 below.
[Tensile strength (TB), elongation (EB)]
Each hose material for a fuel cell was press vulcanized at 160 ° C. for 45 minutes to prepare a vulcanized rubber sheet having a thickness of 2 mm. Subsequently, a JIS No. 5 dumbbell was punched out, and tensile strength (TB) and elongation (EB) were evaluated according to JISK 6251. In addition, about tensile strength (TB) and elongation (EB), it can be said that it is so favorable that a value is large.
[Hardness (HA)]
Using the vulcanized rubber sheet produced as described above, the hardness (durometer type A) was measured according to JIS K 6253.
(Compression set)
Using each fuel cell hose material, compression set was measured in accordance with JIS K 6262 under the condition of −25 ° C. × 24 hours.
[Volume resistivity]
The volume resistivity was measured according to JIS K 6911 using each fuel cell hose material. About volume resistivity, it can be said that it is excellent in electrical insulation, so that a value is high.
[Conductivity of the extracted solution]
The vulcanized rubber sheet prepared as described above was punched into a size of 28 mm × 28 mm × 2 mm. This was sealed in a propylene container together with 50 ml of pure water (1.0 μS / cm), heat-treated at 100 ° C. for 168 hours, and then the conductivity of the resulting extracted solution at 25 ° C. was measured with a conductivity meter (Horiba Seisakusho). Measurement was performed using CONDUCTIVITYMETER D-24). The evaluation of low extractability was evaluated as 場合 when the conductivity was less than 3 μS / cm, ○ when the conductivity was 3 to 5 μS / cm, and × when the conductivity was more than 5 μS / cm.
[0037]
[Table 1]

[0038]
[Table 2]

[0039]
From the above results, it can be seen that all of the examples have high hardness and are excellent in all the characteristics of compression set, electrical insulation and low extractability. It can be seen that the product of Example 5 has a higher toluene coloring permeability than that of the conventional product, that is, uses clean carbon black with a small amount of unburnt, and thus further improves the low extractability.
[0040]
On the other hand, since the product of Comparative Example 1 does not contain an ethylene-olefin resin as an organic filler, it can be seen that the elongation decreases, the hardness is low, and the electrical insulation is inferior. It can be seen that the product of Comparative Example 2 is highly filled with carbon black and thus has high hardness, but is elongated and has poor electrical insulation. Since the product of Comparative Example 3 uses carbon black and silica in combination, the electrical insulation is excellent, but the low extractability is remarkably inferior. Although the comparative example 4 product mix | blends polyethylene resin as a filler, since the crystallinity of polyethylene resin is high, it turns out that it is inferior to compression set property.
[0041]
【The invention's effect】
As described above, the fuel cell hose material of the present invention is obtained by blending an ethylene-olefin-based resin as an organic filler with an ethylene-propylene-diene terpolymer (EPDM). As described above, the present invention does not use an ethylene-olefin-based resin as a polymer, but is blended in EPDM as an organic filler, so that it has excellent electrical insulation and an inorganic filler such as silica is used. Since there is no elution of Si elements and ions, it is excellent in low extractability. In addition, since the ethylene-olefin resin used as the organic filler is dispersed in a state of being compatible with each other in EPDM, the mechanical properties of EPDM are not impaired, and the kneadability of both is excellent. Yes. In addition, ethylene-olefin resins have lower crystallinity than ordinary resins such as polyethylene resins, have intermediate crystallinity between elastomers and resins, and have the characteristics of both elastomers and resins. The distortion characteristics are also good.
[0042]
Further, when the blending ratio of the ethylene-olefin resin is set within a specific range, the low extractability and the electrical insulation are further improved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a dispersion state of an ethylene-olefin resin in a fuel cell hose material of the present invention.
[Explanation of symbols]
1 EPDM
2 Ethylene-olefin resin 3 Carbon black

Claims (4)

A fuel cell hose material comprising an ethylene-propylene-diene terpolymer and an ethylene-olefin resin as an organic filler. 2. The fuel cell hose material according to claim 1, wherein the blending ratio of the ethylene-olefin resin is in the range of 2 to 40 parts by weight with respect to 100 parts by weight of the ethylene-propylene-diene terpolymer. 3. The fuel cell hose material according to claim 1, wherein the ethylene-olefin resin is an ethylene-octene resin. A fuel cell hose formed by forming the fuel cell hose material according to any one of claims 1 to 3 into a hose shape.

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