JP4404205B2 - Polyphenylene sulfide resin-silicone rubber composite material, fuel cell separator and fuel cell using the same - Google Patents

Description

The present invention relates to a composite material of a polyphenylene sulfide resin molded article excellent in adhesiveness to silicone rubber and silicone rubber, a fuel cell separator using the molded article of a polyphenylene sulfide resin composition, and a fuel cell.

  Polyphenylene sulfide resin has excellent heat resistance, rigidity, dimensional stability, flame retardancy, and other suitable properties as engineering plastics. Therefore, various electrical / electronic parts, machine parts, and automobile parts are mainly used for injection molding. It is used for such purposes. Silicone rubber, on the other hand, is also excellent in heat resistance, cold resistance, weather resistance and electrical properties. Similarly, electrical and electronic parts, mechanical parts and automobile parts, OA equipment and precision parts, as well as architectural gaskets and indoor and outdoor It is used in various fields such as insulating materials.

  In particular, a composite material in which polyphenylene sulfide resin and silicone rubber are integrated can be expected to have high performance as the above-mentioned various parts and modules, for example, when the housing is used as polyphenylene sulfide resin and the seal portion is used as silicone rubber. . However, it is difficult to bond the polyphenylene sulfide resin and the silicone rubber only by curing the silicone rubber composition on the polyphenylene sulfide resin, and a method using a primer is common. Not only does the process become complicated, but there also arises a problem that adhesion becomes poor due to smearing of the primer or uneven drying. In recent years, problems with the work environment have also been pointed out because solvents are used for primer application.

  Several studies have been made for the purpose of improving the adhesion of polyphenylene sulfide resin to silicone. For example, a method for improving silicone adhesion by blending an epoxy resin cured product with a polyarylene sulfide resin (Patent Document 1: Japanese Patent Application Laid-Open No. 7-11136), a polyarylene containing a paraarylene sulfide unit and a metaarylene sulfide unit. There is a method (Patent Document 2: JP-A-8-269200) for improving adhesiveness with silicone by sulfide. Furthermore, by adding magnesium oxide to a polyphenylene sulfide resin, a method of obtaining good adhesion with a silicone resin or a silicone rubber, particularly a silicone rubber obtained from an addition-curing type silicone rubber composition (Patent Document 3: Japanese Patent Laid-Open Publication No. 2003-208867) No. 2003-96299) has been proposed. However, although all of these methods have a certain effect of improving adhesiveness, they are not particularly satisfactory in terms of adhesion durability.

JP 7-11136 A JP-A-8-269200 JP 2003-96299 A Japanese Patent Publication No. 45-3368 Japanese Patent Publication No. 52-12240 JP 59-131650 A Japanese Patent Laid-Open No. 58-2004045 JP-A-58-20406 JP 2003-323900 A

The present invention has been made to solve the above problems, adhesion to silicone rubber polyphenylene sulfide resin, in particular improved adhesion durability, composite material of the shaped body and the silicone rubber of the polyphenylene sulfide resin composition Another object of the present invention is to provide a fuel cell separator in which a molded article of a polyphenylene sulfide resin composition is formed, and a fuel cell using the same.

  As a result of intensive studies to achieve the above object, the present inventor has obtained a molded product obtained by molding a polyphenylene sulfide resin composition obtained by adding a certain amount of silicone resin to a polyphenylene sulfide resin. It has been found that the adhesiveness, particularly the adhesive durability such as heat resistance, weather resistance, and chemical resistance, has been dramatically improved.

  Then, the molded body obtained by molding the polyphenylene sulfide resin composition and the silicone rubber composition are brought into contact with each other to cure the silicone rubber composition, or when the polyphenylene sulfide resin composition is molded, A polyphenylene sulfide resin-silicone rubber composite material in which the molded body of the polyphenylene sulfide resin composition and the silicone rubber are firmly bonded is obtained by bringing the silicone rubber composition into contact with the molded / cured product. It is very suitable as a component of solid polymer fuel cell separators suitable for various electric / electronic parts, automobile parts, etc., especially for automobiles and households. By using such separators, Found that a fuel cell with excellent durability can be obtained. Are those able to complete the present invention.

That is, the present invention relates to a polyphenylene sulfide resin molded article obtained by molding a polyphenylene sulfide resin composition containing 100 parts by mass of polyphenylene sulfide and 0.5 to 30 parts by mass of a silicone resin, and a cured product of the silicone rubber composition. And a polyphenylene sulfide resin -silicone rubber composite material characterized by being bonded to each other.

Furthermore, the present invention provides a fuel cell separator in which a base member made of metal or conductive resin and a thermoplastic resin member provided along the outer periphery thereof are integrally formed via a silicone rubber member. A separator for a fuel cell, wherein the thermoplastic member is formed of a molded product of a polyphenylene sulfide resin composition comprising 100 parts by mass of polyphenylene sulfide and 0.5 to 30 parts by mass of a silicone resin ; and A fuel cell comprising a single cell in which an electrode structure including a catalyst layer and a diffusion layer on both surfaces of an electrolyte membrane is sandwiched between a pair of separators, or a stacked cell in which a plurality of separators and electrode structures are alternately stacked. And the fuel cell using the said separator for fuel cells as a separator is provided.

  The polyphenylene sulfide resin composition of the present invention provides a polyphenylene sulfide resin molded article excellent in adhesiveness to silicone rubber, in particular, adhesion durability, and the polyphenylene sulfide resin composition molded article and silicone rubber are firmly bonded. A sulfide resin-silicone rubber composite material can be constituted.

  In addition, this polyphenylene sulfide resin-silicone rubber composite material is very useful as a component of a solid polymer fuel cell separator suitable for various electric / electronic parts, automobile parts, especially automobiles and households. By using such a separator, a fuel cell having excellent durability can be obtained.

Hereinafter, the present invention will be described in more detail.
The polyphenylene sulfide resin composition of the present invention comprises 100 parts by mass of polyphenylene sulfide and 0.5 to 30 parts by mass of a silicone resin.

で示される単位構造を有する重合体である。 The polyphenylene sulfide resin contained in the polyphenylene sulfide resin composition of the present invention has the following structural formula (a):

It is a polymer which has a unit structure shown by these.

で示される単位構造から選ばれる１種又は２種以上を含むものが好適である。上記構造式（ａ）で示される単位構造が７０モル％未満では、耐熱性が損なわれるおそれがある。 As such a polymer, the unit structure represented by the above structural formula (a) is 70 mol% or more (that is, 70 to 100 mol%), preferably 90 mol% or more, particularly 90 to 99.9 mol. %, The balance is the following structural formula

What contains 1 type, or 2 or more types chosen from the unit structure shown by these is suitable. When the unit structure represented by the structural formula (a) is less than 70 mol%, the heat resistance may be impaired.

  Generally, a polyphenylene sulfide resin includes a polymer having a relatively small molecular weight represented by a polymer obtained by the production method described in Japanese Patent Publication No. 45-3368 (Patent Document 4), and Japanese Patent Publication No. 52-12240. There are essentially linear and relatively high molecular weight polymers represented by the polymer obtained by the production method described in (Patent Document 5). In the present invention, polyphenylene sulfide obtained by any method Although it is possible to use a resin and is not particularly limited, a polymer having a relatively low molecular weight such as the former contains a large amount of an oligomer component. Since it may become a catalyst poison when the addition-curing type silicone rubber composition is cured and bonded to the molded body of the resin composition, It is preferable to use a relatively high molecular weight polymers such as.

  In the above polymer, if the polymerization degree is increased by heating in an oxygen atmosphere after polymerization, or by adding a crosslinking agent such as peroxide and heating, the above-mentioned catalyst poisons can be obtained. Since it is possible to avoid the influence, even the polymer having a relatively low molecular weight described above in the present invention can be used effectively. If the polymer is made high in this way, it can be used. There is no problem at all.

  From the above viewpoint, the molecular weight of the polyphenylene sulfide resin to be blended in the polyphenylene sulfide resin composition of the present invention is 1,000 to 1,000,000 in terms of weight average molecular weight (in terms of polystyrene in gel permeation chromatography analysis). Is preferred.

  The melt viscosity of the polyphenylene sulfide resin of the present invention is not particularly limited as long as a molded product can be obtained, but in terms of toughness of the polyphenylene sulfide resin itself, the melt viscosity at 310 ° C. is 100 poise (10 mPa · s) or more. In view of moldability, those having a melt viscosity at 310 ° C. of 10,000 poise (1,000 mPa · s) or less are preferred.

  The polyphenylene sulfide resin composition of the present invention includes a silicone resin (that is, an organopolysiloxane resin having a three-dimensional network molecular structure) in order to obtain sufficient adhesion between the molded product of the polyphenylene sulfide resin composition and the silicone rubber. ) Is essential.

As this silicone resin, what is represented by the following average compositional formula (1) is suitable.
R _n SiO _{(4-n) / 2} (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, preferably an alkoxy group having 1 to 6 carbon atoms, or a hydroxyl group. N is 0 <n <2, preferably 0.2 <n <1.8, more preferably 0.5 <n ≦ 1.5, and still more preferably 0.8. (It is a positive number satisfying ≦ n ≦ 1.5.)

  Here, as the unsubstituted or substituted monovalent hydrocarbon group represented by R, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, Hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group and other alkyl groups, phenyl group, tolyl group, xylyl group, naphthyl group and other aryl groups, benzyl group, phenylethyl group, phenylpropyl group and other aralkyl groups, Alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, etc., and part or all of the hydrogen atoms of these groups are fluorine, bromine, chlorine, etc. Substituted by halogen atoms, cyano groups, etc., such as chloromethyl group, chloropropyl group, bromoethyl , Trifluoropropyl group, cyanoethyl group and the like. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a phenoxy group.

Especially, what contains a phenyl group as said R is preferable, and what is represented by the following average compositional formula (2) is more suitable.
R ¹ _x (C ₆ H ₅ ) _y SiO _{(4-xy) / 2} (2)
(Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group (excluding an unsubstituted phenyl group), an alkoxy group or a hydroxyl group, and may be the same or different. X and y are 0 <x + y. <2, preferably 0.2 <x + y <1.8, more preferably 0.5 <x + y ≦ 1.5, more preferably 0.8 ≦ x + y ≦ 1.5, and 0 <y / (x + y) ≦ 1.0, preferably 0.1 <y / (x + y) ≦ 1.0, more preferably a positive number satisfying 0.15 ≦ y / (x + y) ≦ 1.0.

Here, the unsubstituted or substituted monovalent hydrocarbon group represented by R ¹ is preferably the same as those exemplified as R above except for an unsubstituted phenyl group, preferably excluding an aryl group and an aralkyl group. It is done.

  The molecular weight of the silicone resin is not particularly limited and can be used from a low-viscosity liquid to a high-viscosity water-like or solid, but the weight average molecular weight (polystyrene conversion in gel permeation chromatography analysis) is Those of about 100 to 100,000 are particularly suitable.

  Such a silicone resin can be produced by hydrolyzing chlorosilane or alkoxysilane appropriately selected according to the composition of the silicone resin to be produced by a known method in the silicone resin production technology. .

  The compounding amount of these silicone resins is 0.5 to 30 parts by mass, preferably 1 to 25 parts by mass, more preferably 2 to 15 parts by mass, and further preferably 3 to 12 parts by mass with respect to 100 parts by mass of the polyphenylene sulfide resin. Parts, most preferably 5-10 parts by weight. If the amount is less than 0.5 part by mass, sufficient adhesion between the polyphenylene sulfide resin molded product and the silicone rubber cannot be obtained. If the amount exceeds 30 parts by mass, the strength of the polyphenylene sulfide resin molded product is reduced.

  In addition, the polyphenylene sulfide resin composition of the present invention includes additives such as an antioxidant, a heat stabilizer, a lubricant, a crystal nucleating agent, an ultraviolet light inhibitor, a colorant, and a small amount within a range that does not impair the effects of the present invention. Other polymers can be added, and further, a normal peroxide, a crosslinking accelerator such as a metal salt of thiophosphinic acid described in JP 59-131650 A (Patent Document 6), or JP It is also possible to incorporate a crosslinking inhibitor such as dialkyltin dicarboxylate and aminotriazole described in JP-A-58-204045 (Patent Document 7), JP-A-58-20406 (Patent Document 8), etc. It is.

  In the present invention, the fibrous and / or granular reinforcing material is not an essential component, but if necessary, it may be blended within a range not exceeding 300 parts by mass with respect to 100 parts by mass of the total of the polyphenylene sulfide resin and the silicone resin. Is possible. In addition, when mix | blending, 1 mass part or more is preferable from the point which exhibits the effect effectively. Examples of the fibrous reinforcing material include glass fibers, alumina fibers, silicon carbide fibers, ceramic fibers, gypsum fibers, metal fibers and other inorganic fibers and carbon fibers. The granular reinforcing materials include wollastonite, sericite, kaolin, mica, clay, bentonite, asbestos, talc, alumina silicate and other metals, alumina, fumed silica, magnesium oxide, zirconium oxide, titanium oxide and other metals. Examples include oxides, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and magnesium sulfate, glass beads, boron nitride, and silica. These may be solid or hollow. Good.

  The method for producing the polyphenylene sulfide resin composition of the present invention is not particularly limited, but the mixture of raw materials is supplied to a generally known melt kneader such as a single or twin screw extruder, a Banbury mixer, a kneader, a mixing roll, etc. 280 A typical example is a method of melt-kneading at a temperature of ˜380 ° C. There is no restriction | limiting in particular in the mixing order of a raw material.

  The molded article of the polyphenylene sulfide resin composition of the present invention has good adhesion to silicone rubber and is excellent for producing a polyphenylene sulfide resin-silicone rubber composite material in which both are integrated. As a method for producing such an integrated composite material, a molded product obtained by molding the polyphenylene sulfide resin composition of the present invention is brought into contact with an uncured (unvulcanized) silicone rubber composition. Examples thereof include a method of curing the silicone rubber composition, and a method of molding and curing by contacting the polyphenylene sulfide resin composition with an uncured (unvulcanized) silicone rubber composition at the time of molding the polyphenylene sulfide resin composition. Methods for molding a molded body of a polyphenylene sulfide resin composition alone or as a composite material with silicone rubber include injection molding, compression molding, extrusion molding, two-color molding that continuously cures both, and screen printing. The method may be appropriately selected from methods such as coating and dipping.

  The silicone rubber composition used for the production of this composite material may be any type of organic peroxide curing type, addition curing type, and condensation curing type, but it can be molded in a short time and is excellent in mass productivity. In this respect, a liquid addition-curable silicone rubber composition containing a platinum group metal catalyst is preferred. Moreover, you may use what added the adhesion adjuvant to the addition curable silicone rubber composition from the point of strengthening adhesiveness.

  The addition-curable liquid silicone rubber composition includes a liquid diorganopolysiloxane having two or more alkenyl groups such as vinyl groups in one molecule, and one molecule of hydrogen atom (SiH group) bonded to a silicon atom. A known addition-curable liquid silicone rubber composition containing a liquid organohydrogenpolysiloxane having two or more, preferably three or more, and a platinum group metal-based addition reaction catalyst such as a platinum compound as essential components. Obtained and commercially available, for example, KE1950-40A / B, KE1950-50A / B, KE2000-40A / B, KE2000-50A / B, KE1935A / B, KER1987A / B (manufactured by Shin-Etsu Chemical Co., Ltd.) And two liquid mixture type of B liquid).

  In addition, as the adhesion assistant, for example, at least one selected from alkenyl groups such as vinyl groups, (meth) acryloxy groups, hydrosilyl groups (SiH groups), epoxy groups, alkoxysilyl groups, carbonyl groups, and phenyl groups An organic silicon compound such as a silane having two or more kinds of functional groups, and a linear or cyclic siloxane having 2 to 30 silicon atoms, preferably about 4 to 20 silicon atoms can be used.

  In addition, 1 to 4, preferably 1 to 2, phenylene groups or biphenylene groups in the molecule, and a functional group capable of reacting with a hydrosilyl group (SiH group) in an addition-curable silicone rubber composition by a hydrosilyl addition reaction. An organic compound having 1 or more, preferably 2 to 4 (for example, functional groups such as alkenyl group and (meth) acryloxy group) and having no silicon atom, and benzene having two functional groups in the molecule Examples thereof include dicarboxylic acid esters and benzenetetracarboxylic acid esters having four functional groups in the molecule. The compounding quantity of these adhesion assistants can be 0.1-30 mass parts normally with respect to 100 mass parts of silicone rubber compositions except an adhesion aid, Preferably it can be about 0.5-10 mass parts. . Specific examples of such an adhesion assistant include the following compounds.

  In addition, a self-adhesive type addition-curable liquid silicone rubber composition that is commercially available as an addition of an adhesion assistant to these ordinary silicone rubber compositions can also be used. As such, KE2030-40A / B, KE2030-50A / B, KE2030-60A / B, KE2030-70A / B, X-34-1624A / B, X-34-1625A / B Chemical Industry Co., Ltd. product A liquid and B liquid two-component mixed type).

  In addition, when the molded product of the polyphenylene sulfide resin composition of the present invention and the silicone rubber composition are bonded, sufficiently strong adhesiveness can be obtained without using a primer. It can also be made stronger. As such a primer, primer No. 4. Primer No. 101A / B, primer C, and X-33-156-20 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

  Since the molded product of the polyphenylene sulfide resin composition of the present invention has excellent properties in heat resistance, rigidity, dimensional stability, flame retardancy, etc., various electric / electronic parts, mechanical parts, automobile parts, etc. It can be suitably used as a material for the above. In particular, the composite material in which the molded product of the polyphenylene sulfide resin composition of the present invention and the silicone rubber are integrated has a strong adhesion between the molded product of the polyphenylene sulfide resin composition and the silicone rubber. Suitable for various parts and modules that require both the rigidity of the resin composition and the elasticity of silicone rubber, and require excellent properties in heat resistance, cold resistance, weather resistance, dimensional stability, flame retardancy, electrical properties, etc. Can be used.

  Further, from these excellent performances, the molded article of the polyphenylene sulfide resin composition of the present invention is a material for members constituting a separator of a solid polymer type fuel cell, particularly a base member made of metal or conductive resin. The thermoplastic resin member provided along the outer periphery thereof is suitable as a thermoplastic resin member of a fuel cell separator formed integrally with a silicone rubber member.

  The fuel cell needs almost no fossil fuel to pay attention to resource depletion, generates almost no noise in power generation, and can achieve a higher energy recovery rate than other power generation engines. Due to its superior properties, it has been developed as a relatively small power plant for buildings and factories, and has been partially put into practical use. In particular, polymer electrolyte fuel cells operate at a lower temperature than other types of fuel cells, so there is less concern about the corrosion of the components that make up the cell, and relatively low It is characterized by being capable of discharging a large current, and is attracting attention not only for home cogeneration but also as an alternative to in-vehicle internal combustion engines.

  Among the components constituting this polymer electrolyte fuel cell, a separator is generally formed by forming a plurality of parallel grooves on both sides or one side of a flat plate, and generates power with a gas diffusion electrode in the fuel cell. In addition to transmitting the electricity to the outside, the groove plays a role of securing a flow path for the reactive gas flowing into the fuel cell and a flow path for draining water generated in the groove during power generation.

  Such a separator for a fuel cell is required to be smaller and thinner, and it is important to have excellent durability because a large number of separators are used in an overlapping manner. Furthermore, since acid gas is generated in the electrolyte membrane part, it goes without saying that the acid resistance of the material used for the separator and the sealing material is necessary.

  Recently, it has been proposed that an elastic member functioning as a gasket is formed on the outer peripheral portion of the separator, and the separator and the seal member are integrated to reduce the size and thickness of the fuel cell. For example, Japanese Patent Laid-Open No. 2003-323900 (Patent Document 9) proposes a separator in which a central part is a metal member and an outer peripheral part is a resin member, and these are coupled via an elastic member. In this separator, the gas passage and the generated water passage are formed in the resin member, and thereby the corrosion resistance of the gas passage and the generated water passage against the gas and the generated water can be ensured. The sulfide resin composition can be used as a material for a resin member of such a separator.

  That is, the present invention provides a thermoplastic member for a fuel cell separator in which a metal or conductive resin base member and a thermoplastic resin member provided along the outer periphery thereof are integrally formed via a silicone rubber member. By using the molded product of the polyphenylene sulfide resin composition, it is possible to take advantage of the characteristics of the polyphenylene sulfide resin and the silicone rubber even when various kinds of silicone rubber having excellent resistance are used as the elastic member used in the fuel cell. On the other hand, it is possible to constitute a separator having excellent adhesion between the resin member, which is a molded body of the polyphenylene sulfide resin composition, and the elastic member, which is silicone rubber, and particularly excellent in acid resistance durability.

  In addition, a single cell in which an electrode structure including a catalyst layer and a diffusion layer on both surfaces of an electrolyte membrane is sandwiched between a pair of separators, or a plurality of separators and the above electrode structures are alternately stacked. By using it as a separator of a fuel cell provided with the laminated cell, a solid polymer fuel cell having excellent durability can be configured.

  An example of the structure of the fuel cell separator and the fuel cell according to the present invention will be described with reference to the drawings, for example, as shown in FIGS. 1 and 2 are exploded views showing an example of a polymer electrolyte fuel cell including the fuel cell separator of the present invention.

  In this fuel cell 10, a negative electrode 15 and a positive electrode 16 are arranged on the upper surface 11 a side and the lower surface 11 b side of the electrolyte membrane 11, respectively, and an upper fuel cell separator 20 is superimposed on the negative electrode 15, and The fuel cell separator 20 is superposed. The separator 20 is provided with a thermoplastic resin member 30 around an outer periphery of a base member 22 made of metal or conductive resin, and the base member 22 and the thermoplastic resin member 30 are interposed via a silicone rubber member 40. It is integrally formed. In addition, the thermoplastic resin member 30 is provided with a hydrogen gas passage 31, an oxygen gas passage 32, a generated water passage 33, and projecting seal portions 34 and 41. In the figure, 12 is a hydrogen gas passage, 13 is an oxygen gas passage, and 14 is a product water passage.

  According to the fuel cell 10, hydrogen gas is supplied through the hydrogen gas passages 31 and 12 as indicated by an arrow A, and the hydrogen gas in the hydrogen gas passages 31 and 12 is directed toward the upper base member 22 as indicated by an arrow B. In addition, oxygen gas can be supplied through the oxygen gas passages 32 and 13 as indicated by an arrow C, and the oxygen gas in the oxygen gas passages 32 and 13 can be guided toward the lower base member 22 as indicated by an arrow D.

By introducing hydrogen gas to the base member 22, hydrogen molecules (H ₂ ) are brought into contact with the catalyst contained in the negative electrode 15, and oxygen molecules (O ₂ ) are introduced into the catalyst contained in the positive electrode 16 by introducing oxygen gas to the base member 22. ) Are brought into contact with each other, and electrons e ⁻ flow as shown by arrows to generate current. At this time, generated water (H ₂ O) is generated from hydrogen molecules (H ₂ ) and oxygen molecules (O ₂ ), and this generated water is transferred from the base member 22 to the generated water passages 14 and 33 as indicated by arrow E. The produced water thus led is caused to flow through the produced water passages 14 and 33 as indicated by arrows F.

  And in this invention, in the separator for fuel cells of such a structure, this thermoplastic resin member 30 is formed with the molded object of the polyphenylene sulfide resin composition of this invention.

  1 and 2 described above, a fuel cell including a single cell in which an electrode structure including a catalyst layer and a diffusion layer on both surfaces of an electrolyte membrane is sandwiched between a pair of separators is shown. However, the present invention is not limited to this. The fuel cell may be provided with a stacked cell in which a plurality of separators and the above electrode structures are alternately stacked.

  Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Silicone resin (I)
Trimethylchlorosilane, dimethylchlorosilane, and phenyltrichlorosilane were hydrolyzed, washed with water, neutralized, and then the solvent was removed to obtain a silicone resin that was solid at room temperature represented by the following average composition formula.
(CH ₃ ) _1.11 (C ₆ H ₅ ) _0.35 (OH) _0.02 SiO _1.26

Silicone resin (II)
Dimethyldimethoxysilane and phenyltrimethoxysilane were polymerized in the presence of an alkali catalyst. After neutralization, the solvent was removed to obtain a solid silicone resin at room temperature represented by the following average composition formula.
(CH ₃ ) _0.55 (C ₆ H ₅ ) _0.75 (CH ₃ O) _0.05 SiO _1.33

Silicone rubber composition (I)
100 parts by mass of KE1950-50A (manufactured by Shin-Etsu Chemical Co., Ltd.), an addition-curable liquid silicone rubber composition, and γ-glycidoxypropyltrimethoxysilane (trade name KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) 2 The silicone rubber composition (I) -A and KE1950-50B (manufactured by Shin-Etsu Chemical Co., Ltd.) are used as they are as the silicone rubber composition (I) -B. A mixture of I) -A and silicone rubber composition (I) -B at 1: 1 (mass ratio) was designated as silicone rubber composition (I).

Silicone rubber composition (II)
X-34-1625A and B (manufactured by Shin-Etsu Chemical Co., Ltd.), which are self-adhesive addition-curing liquid silicone rubber compositions, were converted into silicone rubber composition (II) -A and silicone rubber composition (II) -B, respectively. The silicone rubber composition (II) -A and the silicone rubber composition (II) -B were mixed at a ratio of 1: 1 (mass ratio) to obtain a silicone rubber composition (II).
A 0.5 L autoclave equipped with a polyphenylene sulfide resin synthesis stirrer was charged with 0.6 mol of Na ₂ S · 2.9H ₂ O and 150 g of N-methyl-2-pyrrolidone and gradually stirred while stirring under a nitrogen stream. The temperature was raised to 200 ° C. to distill 21.2 g of water. After cooling the system to 170 ° C., 0.6 mol of p-dichlorobenzene was added together with 50 g of N-methyl-2-pyrrolidone, and the system was sealed under a nitrogen stream. The system was heated to 225 ° C. and polymerized for 2 hours, then heated to 250 ° C. over 30 minutes, and further polymerized at 250 ° C. for 3 hours. After completion of the polymerization, the slurry cooled to room temperature is poured into a large amount of water to precipitate the polymer, filtered, repeatedly washed with pure water, and then heated and vacuum dried overnight to obtain a single polymer. Released.

[Examples 1-8, Comparative Examples 1-10]
Production of Polyphenylene Sulfide Resin Composition (Pellets) The polyphenylene sulfide resin and the silicone resin (I) or silicone resin (II) were previously uniformly mixed with a tumbler. Then, using a twin screw extruder with a screw diameter of φ37 mm, while supplying the glass fiber from the side feeder, the cylinder temperature was adjusted so that the temperature from the hopper to the head was 245 ° C. (hopper side) to 300 ° C. (head side). Controlled, melt-kneaded and pelletized to obtain a polyphenylene sulfide resin composition. The amount of each component is shown in Tables 1 and 2.

  Using the polyphenylene sulfide resin composition and the silicone rubber compositions (I) and (II), the following physical properties were evaluated. The results are shown in Tables 1 and 2.

Production of resin plate The pellet was injection molded at a cylinder temperature of 330 ° C. and a mold temperature of 150 ° C. to produce a 150 mm × 150 mm × 2 mm plate, cut into 75 mm × 25 mm × 2 mm, and a sample for confirming adhesion to silicone A resin plate was used.

Preparation of Adhesive Test Piece of Silicone Rubber and Resin Rubber thickness that allows silicone rubber composition (I) or silicone rubber composition (II) to be press-molded on the sample resin plate and only an area of 10 mm × 25 mm adheres. A 2 mm 180 ° peel test piece was prepared. The molding conditions were such that the film was press-cured at 150 ° C. for 5 minutes at a pressure of about 80 kgf / cm ² , then removed from the mold and post-cured at 150 ° C. for 2 hours in an oven.

Physical property evaluation Bending strength: Conforms to JIS K 7171.
Adhesiveness: How much rubber is adhered to the adhesive surface after peeling by 180 ° (cohesive failure rate) is visually determined as a percentage of the area (the higher the numerical value, the better the adhesiveness).
Acid resistance: A sample for adhesion test prepared in sulfuric acid having a pH of 1 in a pressure vessel was immersed and left in an oven at 95 ° C. for 100 hours. After leaving, the pressure vessel is taken out from the oven, cooled for 2 hours, the inside sample is taken out, a 180 ° peel test is performed, and the same determination as the above adhesiveness is made.
Cell durability: MEA (Membrane Electrode Assembly) is sandwiched between two separators, and the state after power generation for 1,000 hours is determined. “◯” indicates that there was no abnormality after power generation, “×” indicates that the silicone peeled off or cracked in the resin part, and “−” indicates that the evaluation was not performed.

It is a disassembled perspective view of a fuel cell provided with the separator for fuel cells of this invention. It is a fragmentary sectional view in alignment with line 2-2 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell 11 Electrolyte membrane 12, 31 Hydrogen gas passage 13, 32 Oxygen gas passage 14, 33 Production water passage 15 Negative electrode 16 Positive electrode 20 Separator 22 Base member 30 Thermoplastic resin member 34, 41 Protruding seal part 40 Silicone rubber member

Claims (13)

A polyphenylene sulfide resin molded product formed by molding a polyphenylene sulfide resin composition containing 100 parts by mass of polyphenylene sulfide and 0.5 to 30 parts by mass of a silicone resin and a cured product of a silicone rubber composition are bonded to each other. A polyphenylene sulfide resin -silicone rubber composite material . The silicone resin has the following average composition formula (1)
R _n SiO _{(4-n) / 2} (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group, alkoxy group or hydroxyl group, and may be the same or different. N is a positive number satisfying 0 <n <2.)
The polyphenylene sulfide resin -silicone rubber composite material according to claim 1, wherein The silicone resin has the following average composition formula (2)
R ¹ _x (C ₆ H ₅ ) _y SiO _{(4-xy) / 2} (2)
(Wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group (excluding an unsubstituted phenyl group), an alkoxy group or a hydroxyl group, and may be the same or different. X and y are 0 <x + y. <2 and a positive number satisfying 0 <y / (x + y) ≦ 1.0.)
The polyphenylene sulfide resin -silicone rubber composite material according to claim 2, wherein The polyphenylene sulfide resin-silicone rubber composite material according to any one of claims 1 to 3, wherein the silicone rubber composition is an addition-curable liquid silicone rubber composition containing a platinum group metal catalyst. . 5. The polyphenylene sulfide resin-silicone rubber composite material according to claim 4, wherein the silicone rubber composition contains an adhesion aid. A silane or siloxane having an adhesion aid of two or more functional groups selected from an alkenyl group, a (meth) acryloxy group, a hydrosilyl group (SiH group), an epoxy group, an alkoxysilyl group, a carbonyl group, and a phenyl group;
An organic compound having 1 to 4 phenylene groups or biphenylene groups and one or more alkenyl groups or (meth) acryloxy groups in the molecule and having no silicon atom,
A benzenedicarboxylic acid ester having two alkenyl groups or (meth) acryloxy groups in the molecule, and
Benzenetetracarboxylic acid ester having four alkenyl groups or (meth) acryloxy groups in the molecule
The polyphenylene sulfide resin-silicone rubber composite material according to claim 5, wherein the composite material is selected from the group consisting of: A fuel cell separator in which a base member made of metal or conductive resin and a thermoplastic resin member provided along the outer periphery thereof are integrally formed via a silicone rubber member, wherein the thermoplastic member is A separator for a fuel cell, which is formed of a molded product of a polyphenylene sulfide resin composition containing 100 parts by mass of polyphenylene sulfide and 0.5 to 30 parts by mass of a silicone resin . The silicone resin has the following average composition formula (1)
R _n SiO _{(4-n) / 2}             (1)
(In the formula, R is an unsubstituted or substituted monovalent hydrocarbon group, alkoxy group or hydroxyl group, and may be the same or different. N is a positive number satisfying 0 <n <2.)
The fuel cell separator according to claim 7, which is represented by: The silicone resin has the following average composition formula (2)
R ¹ _x (C ₆ H _Five ) _y SiO _{(4-x-y) / 2}             (2)
(Wherein R ¹ Is an unsubstituted or substituted monovalent hydrocarbon group (excluding an unsubstituted phenyl group), an alkoxy group or a hydroxyl group, which may be the same or different. x and y are positive numbers satisfying 0 <x + y <2 and 0 <y / (x + y) ≦ 1.0. )
The fuel cell separator according to claim 8, which is represented by: 10. The fuel cell separator according to any one of claims 7 to 9 , wherein the silicone rubber member is formed of a cured product of an addition curable liquid silicone rubber composition containing a platinum group metal catalyst. . 11. The fuel cell separator according to claim 10, wherein the silicone rubber composition is formulated with an adhesion assistant. A silane or siloxane having an adhesion aid of two or more functional groups selected from an alkenyl group, a (meth) acryloxy group, a hydrosilyl group (SiH group), an epoxy group, an alkoxysilyl group, a carbonyl group, and a phenyl group;
An organic compound having 1 to 4 phenylene groups or biphenylene groups and one or more alkenyl groups or (meth) acryloxy groups in the molecule and having no silicon atom,
A benzenedicarboxylic acid ester having two alkenyl groups or (meth) acryloxy groups in the molecule, and
Benzenetetracarboxylic acid ester having four alkenyl groups or (meth) acryloxy groups in the molecule
The fuel cell separator according to claim 11, wherein the fuel cell separator is selected from the group consisting of: A fuel cell comprising a single cell in which an electrode structure including a catalyst layer and a diffusion layer on both surfaces of an electrolyte membrane is sandwiched between a pair of separators, or a stacked cell in which a plurality of separators and electrode structures are alternately stacked. A fuel cell comprising the separator for a fuel cell according to any one of claims 7 to 12 as the separator.

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