JP2006032106A - Hose for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hose for a fuel cell excellent in a barrier property and flexibility. <P>SOLUTION: On the hose for the fuel cell having a pipe-shaped rubber layer contacting fluid, the rubber layer is formed by using a rubber layer material composed of at least one kind of rubber material selected from (A) butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber; and (B) polybutene as essential components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hose for a fuel cell, and more specifically, a hose for a fuel cell that can be used for a pure water piping hose used in a fuel cell system, a hydrogen hose such as a hydrogen piping or a hydrogen-containing water piping, and the like. It is about.

  As a next-generation power generation method, a power generation method using a fuel cell system (in particular, a polymer electrolyte fuel cell) is considered promising. It is said that the performance of the power generation site in this fuel cell system is significantly reduced by external contaminants such as sulfur or metal ions. Therefore, hoses used in these fuel cell systems are required to be clean with low extractability (properties that are difficult to be extracted by water or the like flowing through the hose). Further, when the fuel cell system is used in a vehicle, how to cool a large amount of generated heat is one of the problems. Therefore, the role of the cooling system is said to be extremely important. However, if the conductivity of the cooling water (LLC or the like) increases, there is a concern of causing an electrical short circuit, and the battery of the internal fluid (water or LLC). It is required for a hose used in a fuel cell system to maintain insulation, that is, to suppress extraction of ions and not to increase fluid conductivity.

  For this reason, SUS pipes with little ion elution have been often used so far. However, when SUS pipes are used, there is a problem that they are inferior in assemblability, vibration absorption and flexibility because of their high rigidity.

Therefore, recently, a rubber hose using rubber is being used as a fuel cell hose instead of the SUS pipe. In addition, the fuel cell hose has water permeability resistance that blocks or reduces the permeation of water from the inside of the hose to the outside, and gas resistance resistance that blocks or reduces the permeation of gases such as hydrogen gas, nitrogen gas, and oxygen gas. Therefore, butyl rubber and ethylene-propylene-diene rubber (EPDM), which are excellent in barrier properties and extraction resistance, are used (for example, see Patent Document 1).
JP 2003-278958 A

  However, the hose described in Patent Document 1 has insufficient barrier properties such as water permeation resistance and gas permeation resistance depending on the amount of compounding materials (reinforcing agent, filler, softening agent, etc.) and is flexible. There is a difficulty that it is inferior.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel cell hose excellent in barrier properties and flexibility.

In order to achieve the above object, a fuel cell hose according to the present invention is a fuel cell hose having a tubular rubber layer in contact with a fluid, and the rubber layer comprises the following (A) and (B): It is configured to be formed using a rubber layer material having an essential component.
(A) At least one rubber selected from the group consisting of butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber.
(B) Polybutene.

Conventionally, as hose materials for fuel cells, butyl rubber or EPDM blended with process oil has been used, but it has insufficient barrier properties such as water permeability and gas permeability and is flexible. It was inferior to. The inventor has conducted extensive research focusing on oils and polymers used in order to obtain a fuel cell hose excellent in barrier properties and flexibility. And when it replaced with process oil and liquid polymer was used, the compatibility of rubber | gum and liquid polymer was found favorable, and barrier property and a softness | flexibility improved, and it reached | attained this invention. That is, since the polybutene is mainly composed of isobutylene [—C (CH ₃ ) ₂ CH ₂ —], the permeation of gas or the like is blocked by the steric hindrance structure of a large number of methyl groups in the molecular structure, resulting in barrier properties. In addition, the polybutene is a liquid polymer and acts as a plasticizer. Therefore, it is considered that the hardness of the hose is lowered and the flexibility is improved.

  Thus, in the fuel cell hose of the present invention, the tubular rubber layer in contact with the fluid is at least one rubber selected from the group consisting of butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber. The rubber layer material is formed by blending (B component) with (B component). Therefore, the steric hindrance structure of the methyl group present in the molecular structure of the polybutene (B component) improves the barrier properties such as water permeability resistance and gas permeability resistance, and by blending the polybutene (B component), the hose The hardness of the hose is reduced and the flexibility of the hose is also improved.

  Moreover, barrier property and a softness | flexibility improve more that the compounding quantity of the said polybutene (B component) is 3 weight part or more with respect to 100 weight part of specific rubber | gum (A component).

  When a tubular rubber layer in contact with a fluid is formed using a rubber layer material containing a white filler together with the specific rubber (component A) and polybutene (component B), the barrier property and flexibility are further increased. improves.

  Next, embodiments of the present invention will be described in detail.

  As the fuel cell hose of the present invention, for example, as shown in FIG. 1, there is one in which a reinforcing layer 2 is formed on the outer peripheral surface of a rubber inner layer 1 and an outer layer 3 is further formed on the outer peripheral surface.

In the present invention, the tubular rubber inner layer 1 in contact with the fluid is formed using a rubber layer material containing the following (A) and (B) as essential components, and this is the greatest feature. It is.
(A) At least one rubber selected from the group consisting of butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber.
(B) Polybutene.

  In addition, in this invention, an essential component is with respect to arbitrary components, Comprising: The component which must be contained by a structure is said, and it does not receive quantitative restrictions.

  Specific rubber (component A) that is the material for the rubber layer includes butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene rubber (EPM), and ethylene-propylene-diene rubber (EPDM), either singly or in combination. Used together. Examples of the halogenated butyl rubber include chlorinated butyl rubber (Cl-IIR) and brominated butyl rubber (Br-IIR).

  Here, when blending butyl rubber and halogenated butyl rubber, the weight ratio is preferably within the range of butyl rubber / halogenated butyl rubber = 10/90 to 90/10.

Next, as described above, the polybutene (B component) used together with the specific rubber (component A) is particularly a liquid polymer mainly composed of isobutylene [—C (CH ₃ ) ₂ CH ₂ —]. There is no limitation.

And the number average molecular weight (Mn) of the said polybutene (B component) has the preferable range of 300-3700, Most preferably, it exists in the range of 500-3000. Further, the kinematic viscosity (100 ° C.) of the polybutene (component B) is preferably in the range of ^{2 to} 5700 mm ² / s, particularly preferably in the range of 10 to 4000 mm ² / s. Specific examples of such polybutene (component B) include polybutene HV-1900 manufactured by Shin Nippon Petrochemical Co., Ltd.

  The amount of the polybutene (component B) is preferably 3 parts or more, particularly preferably 5 to 30 parts, relative to 100 parts by weight (hereinafter abbreviated as “part”) of the specific rubber (component A). Within range. That is, when the blending amount of polybutene (component B) is less than 3 parts, the effect of improving barrier properties and flexibility tends to be reduced.

  The rubber layer material may be appropriately blended with the specific rubber (component A) and polybutene (component B) together with a white filler, a vulcanizing agent, carbon black, a plasticizer, and the like.

  The white filler is not particularly limited, and examples thereof include talc, mica, sericite, montmorillonite, silica, and clay. These may be used alone or in combination of two or more.

  Moreover, the compounding amount of the white filler is preferably in the range of 20 to 200 parts, particularly preferably in the range of 40 to 130 parts with respect to 100 parts of the specific rubber (component A). That is, if the blending amount of the white filler is less than 20 parts, the barrier property tends to decrease. Conversely, if the blending amount of the white filler exceeds 200 parts, the hardness increases. This is because the flexibility and vibration absorbability are inferior and the extrusion processability tends to deteriorate.

  The vulcanizing agent is not particularly limited, and examples thereof include sulfur, peroxide vulcanizing agents such as dicumyl peroxide, and resin vulcanizing agents such as alkylphenol-formaldehyde resins. These may be used alone or in combination of two or more.

  Moreover, the compounding amount of the vulcanizing agent is preferably in the range of 0.5 to 20 parts with respect to 100 parts of the specific rubber (component A).

  The blending amount of the carbon black can be adjusted according to desired tensile properties and hardness, but is preferably in the range of 20 to 150 parts with respect to 100 parts of the specific rubber (component A).

  Examples of the plasticizer include aroma oil, naphthenic oil, paraffin oil and the like. These may be used alone or in combination of two or more.

  Next, the reinforcing layer 2 formed on the outer peripheral surface of the rubber inner layer 1 is made of, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyamide (nylon), vinylon, rayon, metal wire or the like. The reinforcing yarn can be configured by braiding with a spiral braid, a knit braid, a blade braid, or the like.

  The material (outer layer material) for forming the outer layer 3 on the outer peripheral surface of the reinforcing layer 2 is not particularly limited. For example, butyl rubber (IIR), chlorinated butyl rubber (Cl-IIR), brominated butyl rubber (Br-IIR). ) Halogenated butyl rubber, acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), fluorine rubber (FKM), epichlorohydrin rubber (ECO) ), A rubber material such as acrylic rubber, silicon rubber, chlorinated polyethylene rubber (CPE), urethane rubber, or the like, which is appropriately mixed with a vulcanizing agent, carbon black, or the like is used. Use acrylic elastomers (TPE) such as acrylics, styrenes, olefins, diolefins, vinyl chlorides, urethanes, esters, amides, fluorines, and silicones, heat shrinkable tubes, etc. Is also possible.

  Here, the hose for a fuel cell of the present invention as shown in FIG. 1 can be produced, for example, as follows. That is, the specific rubber (component A), polybutene (component B) and, if necessary, a vulcanizing agent and the like are blended at a predetermined ratio, and this is kneaded with a Banbury mixer or the like to prepare an inner layer material. Next, this inner layer material is extruded into a tube shape to form the rubber inner layer 1, and then the reinforcing yarn is braided to form the reinforcing layer 2. Next, an outer layer material is extruded on the surface of the reinforcing layer 2. In this manner, a fuel cell hose (see FIG. 1) in which the reinforcing layer 2 is formed on the outer peripheral surface of the rubber inner layer 1 and the outer layer 3 is formed on the outer peripheral surface thereof can be produced.

  The fuel cell hose of the present invention is not limited to the three-layer structure shown in FIG. 1 as long as it has at least a tubular rubber inner layer 1 in contact with a fluid. There may be a configuration in which an intermediate layer (rubber layer) or the like is provided between the inner layer 1 and the reinforcing layer 2 or between the reinforcing layer 2 and the outer layer 3.

  Next, examples will be described together with comparative examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[EPDM]
Esprene 532 manufactured by Sumitomo Chemical Co., Ltd.

[Chlorinated butyl rubber (Cl-IIR)]
Butyl HT1066, manufactured by JSR

〔Carbon black〕
Toast Carbon Co., Ltd., Seast 116

[White filler (talc)]
Nihon Talc Co., Ltd., Microace K-1

[Process oil]
Idemitsu Kosan Co., Ltd., Diana Process PW-380

[Liquid polybutene]
New Japan Petrochemical Co., Ltd., polybutene HV-1900 [Mn: 2900, kinematic viscosity (100 ° C.): 590 mm ² / s]

[Peroxide vulcanizing agent]
Dicumyl peroxide (Nippon Yushi Co., Ltd., Park Mill D)

(Resin vulcanizing agent)
Alkylphenol-formaldehyde resin (Taoka Chemical Industries, Tactrol 201)

[Examples 1 to 4, Comparative Examples 1 and 2]
Each component material shown in Table 1 to be described later was blended in the proportions shown in the same table, and kneaded using a Banbury mixer and a roll to prepare a rubber composition. Subsequently, this rubber composition was press vulcanized at 160 ° C. for 45 minutes to produce a rubber sheet (thickness 2 mm).

  Using the rubber sheets of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are also shown in Table 1 below.

[Initial physical properties]
Each rubber sheet was punched into a JIS No. 5 dumbbell, and tensile strength (TB) and tensile elongation at break (EB) were measured in accordance with JIS K 6251. About tensile strength (TB) and tensile breaking elongation (EB), it can be said that it is so favorable that a value is large.

(Transmission constant)
The permeation constant (mg · mm / cm ² · day) of each rubber sheet was measured using a cup type test jig. That is, a cup type test jig (inner diameter 66 mm, inner volume 135 cm ³ , transmission area 34.2 cm ² ) was prepared, and the rubber sheet was fixed to the lower side of the cup type test jig via a butyl rubber packing. And the pure water (100 cm < ³ >) was filled in the said cup-type test jig, it arrange | positioned so that a rubber sheet and pure water might contact | connect, and it was left to stand in 80 degreeC constant temperature atmosphere. The standing time and the weight loss of pure water were plotted on a graph, and the permeability constant (mg · mm / cm ² · day) was calculated from the slope. As for the permeability constant, it can be said that the smaller the value, the better the water permeability resistance.

[Gas permeability coefficient]
Using each rubber sheet, gas (nitrogen gas) permeation coefficient (× 10 ⁻⁹ ml · cm / cm ² ) per unit thickness using a GTR gas permeation measuring device under the conditions of 80 ° C. based on ASTM D1434-75M method. · Sec · cmHg). It can be said that the smaller the value of the gas permeability coefficient, the better the gas permeability resistance.

[Volume resistivity]
The volume resistivity of each rubber sheet was measured according to JIS K 6911. About volume resistivity, it can be said that it is excellent in electrical insulation, so that a value is high.

  From the above results, since the example products used liquid polybutene, they were excellent in barrier properties, as well as in flexibility and electrical insulation. In addition, in the example product using EPM instead of EPDM, excellent effects similar to those of the example product using EPDM were obtained. Also, in the example product using IIR instead of Cl-IIR, the same excellent effect as that of the example product using Cl-IIR was obtained.

  On the other hand, since the comparative product used process oil instead of liquid polybutene, the barrier properties such as water permeability resistance and gas permeability resistance were inferior, and the electrical insulation was inferior.

  The fuel cell hose of the present invention can be used for a pure water piping hose used in a fuel cell system, a hydrogen hose such as a hydrogen piping, a hydrogen-containing water piping, or the like.

It is a block diagram which shows an example of the hose for fuel cells of this invention.

Explanation of symbols

1 Rubber inner layer 2 Reinforcement layer 3 Outer layer

Claims (3)

A hose for a fuel cell having a tubular rubber layer in contact with a fluid, wherein the rubber layer is formed using a rubber layer material having the following (A) and (B) as essential components: A fuel cell hose.
(A) At least one rubber selected from the group consisting of butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-propylene-diene rubber.
(B) Polybutene.   The hose for a fuel cell according to claim 1, wherein the blending amount of the component (B) is 3 parts by weight or more with respect to 100 parts by weight of the component (A).   The fuel cell hose according to claim 1 or 2, wherein the rubber layer material contains a white filler together with the components (A) and (B).