JP6036273B2 - Rubber composition and outer hood for railway vehicles - Google Patents

Description

  The present invention relates to a rubber composition and an outer hood for a railway vehicle formed using the rubber composition.

The main purpose is to prevent people from falling from the platform to the space created between the train cars and to reduce the air resistance of the connecting part between the vehicles between the railway vehicles (vehicle connecting part). The outer hood is arranged.
The characteristics required for the material of the outer hood for a railway vehicle include, for example, a hardness that does not buckle even when a person leans on, and excellent weather resistance.

As a material satisfying such characteristics, for example, in Patent Document 1, the present applicant selected “from 30 to 100% by mass of natural rubber, and a group consisting of styrene-butadiene rubber, butadiene rubber, and ethylene-propylene-diene rubber”. 100 parts by mass of a rubber component containing 0 to 70% by mass of one or more kinds of rubbers,
A rubber composition comprising the following component (1) or (2):
(1) 30 to 85 parts by mass of aluminum hydroxide, 20 to 50 parts by mass of decabromodiphenyl ether and 10 to 20 parts by mass of ammonium polyphosphate (2) 30 to 90 parts by mass of aluminum hydroxide, 10 to 50 parts by mass of chlorinated paraffin and "3 to 20 parts by mass of antimony trioxide" has been proposed.

JP 2006-176659 A

However, when the present inventor examined the rubber composition described in Patent Document 1, depending on the type of flame retardant to be blended, the rubber flowability at the time of vulcanization is reduced and the appearance is poor or after vulcanization. It became clear that workability at the time of demolding may be inferior.
Then, an object of this invention is to provide the rubber composition which is excellent in the flame retardance, and is excellent in the external appearance after vulcanization, and the workability | operativity at the time of demolding.

As a result of intensive studies to solve the above problems, the present inventor has obtained a rubber composition in which ethylene bis (pentabromobenzene) and a sulfur-containing silane coupling agent are blended in a specific amount with respect to an ethylene-propylene copolymer. When used, it was found that excellent flame retardancy was maintained and the appearance after vulcanization and workability during demolding were excellent, and the present invention was completed.
That is, the present invention provides the following (1) to (3).

  (1) 20 to 40 parts by mass of silica, 10 to 50 parts by mass of silicate mineral, 30 to 80 parts by mass of aluminum hydroxide, and ethylene bis (pentabromo) with respect to 100 parts by mass of the ethylene-propylene copolymer (Benzene) A rubber composition containing 20 to 50 parts by mass, 5 to 30 parts by mass of ammonium polyphosphate, and 0.5 to 5.0 parts by mass of a sulfur-containing silane coupling agent.

  (2) The rubber composition according to (1), which is a rubber composition for an outer hood of a railway vehicle.

  (3) An outer hood for a railway vehicle using the rubber composition described in (1) above as a material.

  As described below, according to the present invention, it is possible to provide a rubber composition that retains excellent flame retardancy and is excellent in appearance after vulcanization and workability during demolding.

It is a typical partial perspective view for demonstrating one Embodiment with the outer hood of this invention attached to the vehicle. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and is a schematic cross-sectional view of a side portion of an outer hood of a railway vehicle when the vehicle travels on a linear rail or a rail having a small curvature. FIG. 6 is a schematic partial perspective view for explaining another shape of the flexible film body 6 constituting the linear member 3 of the outer hood 2. It is explanatory drawing for demonstrating the attachment method of the flexible film body which comprises the linear part of an outer hood. It is explanatory drawing for demonstrating the attachment method of a cyclic | annular outer hood. It is a typical perspective view of the shoulder part member of the outer hood obtained in the Example of this invention. It is typical sectional drawing for demonstrating other embodiment of the state in which the outer hood of this invention was attached to the vehicle. It is BB arrow sectional drawing of FIG.

(Rubber composition)
The rubber composition of the present invention is 20 to 40 parts by mass of silica, 10 to 50 parts by mass of silicate mineral, 30 to 80 parts by mass of aluminum hydroxide, with respect to 100 parts by mass of the ethylene-propylene copolymer. It contains 20 to 50 parts by mass of ethylenebis (pentabromobenzene), 5 to 30 parts by mass of ammonium polyphosphate, and 0.5 to 5.0 parts by mass of a sulfur-containing silane coupling agent.
Next, the essential components and optional components contained in the rubber composition of the present invention will be described in detail.

<Ethylene-propylene copolymer>
If the ethylene-propylene copolymer contained in the rubber composition of the present invention is a copolymer of ethylene and propylene (EPM) and / or a copolymer of ethylene, propylene and a diene monomer (EPDM) There is no particular limitation.

Specific examples of the diene monomer include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene.
Of these, dicyclopentadiene is preferred from the viewpoint of processability.

The iodine value of the EPDM is preferably 3 to 25 and more preferably 3 to 20 from the viewpoint of chemical resistance and weather resistance.
In addition, the ethylene content in the ethylene-propylene copolymer is preferably 90 to 40 mol%, more preferably 80 to 50 mol%, from the viewpoint of vulcanized physical properties such as elongation at break.
Furthermore, the Mooney viscosity at 100 ° C. of the ethylene-propylene copolymer is preferably 30 to 80 and more preferably 50 to 70 from the viewpoint of processability.

<Silica>
The silica contained in the rubber composition of the present invention is not particularly limited.
Specific examples of the silica include hydrous silica, anhydrous silica, precipitated silica, and fumed silica. These may be used alone or in combination of two or more. .

In the present invention, the silica content improves the rubber flowability during vulcanization, so that the appearance after vulcanization is improved, and the workability during demolding is improved. From the reason that the hardness and mechanical properties of rubber products (for example, outer hoods of railway vehicles) are good, it is 20 to 40 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer, and 20 to 30 It is preferable that it is a mass part.
Moreover, the content of the silica is 20 to 80% by mass with respect to the total mass with a silicate mineral described later, because the appearance after vulcanization and the workability at the time of demolding become better. Is preferable, and it is more preferable that it is 20-60 mass%.

<Silicate mineral>
The silicate mineral contained in the rubber composition of the present invention is not particularly limited.
The silicate mineral is preferably a layered silicate (phyllosilicate), and specific examples thereof include clays such as kaolin and wax, mica, smectite, serpentine, talc, chlorite, vermiculite, and the like. These may be used alone or in combination of two or more.
Of these, talc and clay are preferred because the processability is good and the mechanical properties of the rubber product after vulcanization are good.

  In the present invention, the content of the silicate mineral improves the appearance after vulcanization because the rubber flowability during vulcanization is good, and also improves the workability during demolding. For the reason that the hardness and mechanical properties of the rubber product after vulcanization are good, the amount is 10 to 50 parts by weight, preferably 20 to 50 parts by weight with respect to 100 parts by weight of the ethylene-propylene copolymer. .

<Aluminum hydroxide>
The aluminum hydroxide contained in the rubber composition of the present invention is not particularly limited, and conventionally known ones can be used as in Patent Document 1.
In the present invention, the content of the aluminum hydroxide is 30 to 80 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer because the flame retardancy of the rubber product after vulcanization is good. It is preferable that it is 30-60 mass parts.

<Ethylenebis (pentabromobenzene)>
The ethylene bis (pentabromobenzene) contained in the rubber composition of the present invention is not particularly limited, and is also called bis (pentabromophenyl) ethane.

  In the present invention, the content of ethylene bis (pentabromobenzene) is 20% with respect to 100 parts by mass of the ethylene-propylene copolymer because the flame retardancy of the rubber product after vulcanization becomes good. It is -50 mass parts, and it is preferable that it is 20-40 mass parts.

<Ammonium polyphosphate>
The ammonium polyphosphate contained in the rubber composition of the present invention is not particularly limited, and conventionally known ones can be used as in Patent Document 1.
In the present invention, the content of the ammonium polyphosphate is 5 to 30 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer because the flame retardancy of the rubber product after vulcanization is good. It is preferable that it is 5-20 mass parts.

<Sulfur-containing silane coupling agent>
The sulfur-containing silane coupling agent contained in the rubber composition of the present invention is not particularly limited, and any conventionally known silane coupling agent can be used.
Specific examples of the silane coupling agent include 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide, and triethoxysilylpropyl-methacrylate. Monosulfide, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, bis- [3- (triethoxysilyl) -propyl] tetrasulfide, bis- [3- (trimethoxysilyl) -propyl] tetra Examples include sulfide, bis- [3- (triethoxysilyl) -propyl] disulfide, 3-mercaptopropyl-trimethoxysilane, 3-mercaptopropyl-triethoxysilane, and the like. Well, it may be used in combination of two or more thereof.
Of these, a silane coupling agent having a mercapto group is preferred because the mechanical properties of rubber products after vulcanization are good.

  In the present invention, the content of the sulfur-containing silane coupling agent improves the appearance after vulcanization because the rubber flowability during vulcanization is good, and also improves the workability during demolding, Furthermore, the rubber product after vulcanization is 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer, because the rubber product after vulcanization has good hardness and mechanical properties. It is preferable that it is 0.5-3 mass parts with respect to 100 mass parts of the said ethylene-propylene copolymer from the reason for which the breaking strength of a product becomes favorable.

The rubber composition of the present invention can contain various additives as necessary in addition to the rubber component and the flame retardant as long as the object of the present invention is not impaired.
Examples of additives include reinforcing agents (fillers) other than the silica and silicate minerals described above, silica stabilizers, anti-aging agents, antioxidants, pigments, dyes, plasticizers, thixotropic agents, and ultraviolet rays. Examples include absorbents, solvents, surfactants (including leveling agents), dispersants, dehydrating agents, rust preventives, adhesion imparting agents, antistatic agents, and thixotropy imparting agents.
As these additives, those usually used in rubber compositions can be blended in a usual content. Moreover, it can change suitably according to the objective, a use, a required characteristic, etc.
For example, the content of the silica stabilizer (for example, alcohol such as diethylene glycol) is preferably 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer. More preferably, it is 5-2.5 mass parts.

Further, the rubber composition of the present invention may contain an organic peroxide, a vulcanizing agent, a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, etc. within a range that does not impair the purpose of the present invention. it can.
As these vulcanizing agents and the like, those usually used in rubber compositions can be blended with usual contents. Moreover, it can change suitably according to the objective, a use, a required characteristic, etc.
For example, the content of the organic peroxide (for example, dicumyl peroxide) is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the ethylene-propylene copolymer. It is more preferable that
Moreover, it is preferable that content of a vulcanizing agent (for example, sulfur etc.) is 0.05-1.0 mass part with respect to 100 mass parts of said ethylene-propylene copolymers, 0.05-0. More preferably, it is 5 parts by mass.

The method for producing the rubber composition of the present invention is not particularly limited. For example, the above-described ethylene-propylene copolymer, silica, silicate mineral, aluminum hydroxide, ethylene bis (pentabromobenzene), ammonium polyphosphate and A sulfur-containing silane coupling agent and various additives as necessary can be produced by uniformly mixing them with a roll, a kneader, an extruder, a universal agitator or the like.
The rubber composition thus obtained can be vulcanized by mixing a vulcanizing agent and the like, heating to a desired temperature, stirring and mixing.

Since the rubber composition of the present invention contains a specific amount of the above-mentioned components, particularly the ethylene bis (pentabromobenzene) with respect to the ethylene-propylene copolymer, it retains excellent flame retardancy. , Appearance after vulcanization and workability during demolding are improved.
The rubber composition of the present invention can be used in various applications in which the rubber composition is used, but is preferably used in various applications that require these characteristics. Especially, it can use suitably for the outer hood of a railway vehicle, and can be used suitably especially for the outer hood of a subway vehicle in which a flame retardance is requested | required.

[Railway outer cover]
The outer hood of a railway vehicle of the present invention (hereinafter simply referred to as “the outer hood of the present invention”) is an outer hood of a railway vehicle using the rubber composition of the present invention as a material.
The configuration of the outer hood of the present invention is not particularly limited. For example, the outer hood is an annular outer hood that covers the entire circumference of the space between the vehicles at the connecting portion of the front and rear vehicles, and includes a rear end portion of the front vehicle and a rear vehicle. One of the preferred embodiments is an outer hood made of a flexible membrane body having a substantially U-shaped cross section (V-shaped or the like) attached to face the front end of each. Other preferred embodiments include a plate-shaped outer hood (also referred to as “protective rubber”) that covers a part of the space between the vehicles at the connecting portion of the front and rear vehicles.
Here, with respect to the annular outer hood, the upper, lower, left and right linear members (the left and right side surfaces, the ceiling and the floor) that cover the entire circumference of the space between the vehicles, and the shoulders disposed at the four corners connected thereto It is preferable that the flexible film body has a thick flange portion at the attachment portion with the vehicle, and a thin cross-sectional U-shaped (V-shape, etc.) film body at the portion facing the front and rear vehicles. It is preferable to consist of a part, and it is preferable to embed the reinforcement layer inside the flexible membrane.

  Hereinafter, an outer hood of the present invention will be described with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a schematic partial perspective view for explaining an embodiment in which the outer hood of the present invention is attached to a vehicle.
As shown in FIG. 1, an annular outer hood 2 that covers the entire circumference of a space portion between vehicles in a connecting portion of a vehicle 1 is composed of four linear members 3 in the vertical and horizontal directions (left and right side portions, a ceiling portion, and a floor portion). And four shoulder members 4 connecting the four linear members 3 at the four corners. In the figure, reference numeral 5 denotes a passage in the vehicle 1.

2 is a cross-sectional view taken along the line AA in FIG.
As shown in FIG. 2, the linear member 3 of the outer hood 2 includes a flexible film body 6 having a substantially U-shaped cross section. The linear member 3 may be used by coating the rubber composition of the present invention on a woven fabric made of nylon, aramid, PET, or the like as a reinforcing layer in order to increase rigidity and resilience as required. it can.

In FIG. 2, the outer shape of the vehicle connected to the vehicle and the outer hood attached thereto are shown by dotted lines in order to show the relative positional relationship between the front and rear vehicles. That is, the outer hood 2 of the present invention is configured by a flexible film body 6 having a substantially U-shaped cross section that is attached to face the rear end portion of the front vehicle 1 and the front end portion of the rear vehicle 1. .
Here, the outer hood of the present invention preferably has a substantially U-shaped cross section. Specifically, in addition to the U shape, the shape may be a substantially V shape, a substantially semicircular shape, or the like. These shapes can be changed according to the shape of the vehicle used. For example, even if it is substantially V-shaped, it can be non-equal, not equi-lateral.

FIG. 3 is a schematic partial perspective view for explaining another shape of the flexible film body 6 constituting the linear member 3 of the outer hood 2.
As shown in FIG. 3, the flexible film body 6 is thin at the center 7 in the width direction and gradually increases in thickness toward both ends, and is attached to the vehicle 1 at both ends. A portion 8 is formed. As shown in FIG. 2, the flexible film body 6 includes a thick flange portion 8 at a site where the vehicle 1 is attached and a thin cross-section substantially U-shaped (V-shaped, etc.) at a site facing the front and rear vehicles 1. ).

  FIG. 3 shows the case where the flange portions 8 formed at both ends of the flexible film body 6 have shapes protruding in opposite directions. This is the case where the flexible film body 6 is attached to the vehicle. Therefore, there is no problem even if the protruding directions of the flanges 8 formed at both ends of the flexible film body 6 are the same direction.

  FIG. 4 is an explanatory diagram for explaining a method of attaching the flexible membrane body constituting the straight portion of the outer hood, and FIG. 5 is an explanatory diagram for explaining a method of attaching the annular outer hood. .

  As shown in FIG. 4, the flexible film body 6 is attached by attaching one flange portion 8 to the outer peripheral side of the upper, lower, left, and right straight portions of the vehicle 1 so that the end portion is directed toward the inside of the vehicle 1. Thereafter, the other end side is bent in the direction indicated by arrow C in the figure, and the flexible film body 6 is bent so that the cross section of the flexible film body 6 is substantially U-shaped. The attachment of the linear member 3 of the outer hood 2 is completed after attaching to the circumferential side.

  Further, as shown in FIG. 5, a plurality of shoulder members 4 each having a substantially U-shaped cross section with a desired curvature and having a flange portion having an L-shaped cross section inward in the width direction end portion are provided. Installation of the outer hood 2 of the present invention is completed by forming the shoulder member 4 separately from the straight member 3 and attaching it to the vehicle 1 with the longitudinal end of the shoulder member 4 overlapped with the end of the straight member 3. To do.

Although the outer hood of the present invention has been specifically described with reference to one embodiment, the outer hood of the present invention is not limited to this. For example, a through hole 9 (see FIG. 5) is formed on the wall surface of the shoulder member 4 of the outer hood for the purpose of improving workability for fixing the outer hood to the vehicle body and releasing concentrated stress. Alternatively, a notch or the like may be formed in the shoulder member 4.
Further, the outer hood of the present invention is an embodiment in which the outer hood is provided only on the two linear members 3 on the left and right (left and right side portions) in the embodiment shown in FIG. 1, that is, FIGS. 7 and 8 (B- in FIG. 7). As shown in the B cross-sectional view), a plate-shaped outer hood (protective rubber) 12 attached to each side surface of the front and rear vehicles may be used.

Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to this.
1. Preparation of rubber composition (Examples 1-4 and Comparative Examples 1-4)
Ingredients (parts by mass) shown in Table 1 below were added to the components (excluding organic peroxide and sulfur) shown in the same table in a 20 L kneader mixer and mixed for about 15 minutes. Then, the obtained rubber mixture was wound around an 18-inch kneading roll, an organic peroxide and sulfur were added, and kneaded for about 10 minutes to obtain a rubber composition.

2. Production of outer hood of railway vehicle First, a 1 / 2-scale simple molding mold of the outer hood was produced.
Next, using this simple mold, each rubber composition obtained above was press vulcanized at 150 ° C. for 45 minutes to obtain a shoulder member of the outer hood.
FIG. 6 is a schematic perspective view of the shoulder member of the outer hood obtained.
As shown in FIG. 6, a shoulder member 4 having a substantially V-shaped cross section was obtained. The height of the obtained shoulder member 4 is 125 to 130 mm, the length of the outer surface 10 of the hood is 700 mm, the radius of curvature (R) on the outer surface side of the curved portion 11 is 200 mm, and the width of the hood (distance between the flanges 8). Was 70 mm and the V-shaped cross section was equilateral.
The shoulder member 4 shown in FIG. 6 and the symmetrical shoulder member 4 'were also obtained in the same manner.

3. Evaluation Each rubber composition or vulcanized shoulder member obtained was evaluated for processability, appearance, workability during demolding, and flame retardancy by the following methods. These results are shown in Table 1.

<Processability (Rubber flow during vulcanization)>
About the obtained rubber composition, according to the Mooney scorch test method of JIS K 6300-1: 2001, using a Mooney viscometer (L-shaped rotor), Mooney minimum viscosity (Vm, unit: Mooney) at 125 ° C. and Mooney Scorch time was measured. As for the Mooney scorch time, the time (ML5up, unit: minute) required to increase by 5 Mooney from the min torque is displayed.
Here, those having a Mooney minimum viscosity (Vm) greater than 65 can be evaluated as being inferior in rubber flowability during vulcanization, and those having a Mooney minimum viscosity (Vm) of 65 or less are those during vulcanization. It can be evaluated that the fluidity is excellent.

<Appearance>
The appearance of the obtained shoulder member was confirmed visually.
As a result, the shape of the simple molding mold was evaluated as “◯” as excellent in appearance, the rubber flow was slightly insufficient, and the light taste was evaluated as “△” as slightly inferior in appearance. A flow that completely lacked flow and did not conform to the shape of the simple mold was evaluated as “x” as being inferior in appearance.

<Workability during mold removal>
The workability when removing the shoulder member from the simple mold was evaluated according to the following criteria.
In other words, those that are easily peeled off from the simple mold are evaluated as “Good” as being excellent in workability, and cracks are generated, but those that can be removed from the simple mold if carefully peeled off are somewhat inferior in workability. Evaluation was made as “Δ”, and those that were torn and could not be removed from the simple mold were evaluated as “x” as inferior in workability.

<Flame retardance>
(1) Flammability (oxygen index)
The flame retardancy test for the rubber compositions obtained in Comparative Examples 2 to 4 and Examples 1 to 4 was conducted according to JIS K 7201-1: 1999 and JIS K 7201-2: 1999 “Plastic-Oxygen Index Flammability”. The test method was conducted according to the above.
As the test piece, the rubber composition obtained above was vulcanized at 150 ° C. for 45 minutes.
When the oxygen index was determined, the burning lengths of the test pieces were 38 mm and 55 mm, and the burning times were 155 seconds and 187 seconds.
The flame retardant test was conducted 5 times, and the average value of the oxygen index was evaluated. In addition, although it can be said that it is generally flame-retardant if an oxygen index exceeds 21, in recent years, in view of higher safety, 25 or more tends to be required.
(2) Generated gas volume (index)
The amount of gas generated during the flame retardancy test was measured by a method according to BS6853 flame retardant Annex B.
The measured values are represented by an index with the value of Comparative Example 2 being 100, and are shown in Table 1 below. The smaller the index, the smaller the amount of gas generated, which means better flame retardancy.

The components shown in Table 1 are as follows.
・ EDPM: ESPRENE305 (manufactured by Sumitomo Chemical Co., Ltd.)
・ Silica: Nip seal VN3 (made by Nippon Silica)
-Talc: N talc (made by Nippon Talc)
Aluminum hydroxide: Heidilite H-42M (Showa Light Metal Co., Ltd.)
・ Decabromodiphenyl ether: Frame cut BR-100 (manufactured by Tosoh Corporation)
・ Ethylenebis (pentabromobenzene): SAYTEX8010 (manufactured by ALBEMALE CORPORATION)
-Ammonium polyphosphate: Sumisafe P (manufactured by Sumitomo Chemical Co., Ltd.)
・ Sulfur-containing silane coupling agent: Si69 (Evonik Degussa)
Vinyltriethoxysilane: KBE-1003 (manufactured by Shin-Etsu Chemical Co., Ltd.)
・ Diethylene glycol: manufactured by Maruzen Petrochemical Co., Ltd. ・ Zinc oxide: Ginseng R (manufactured by Toho Zinc Co., Ltd.)
・ Stearic acid: LUNAC YA (manufactured by Kao Corporation)
-Paraffin oil: Machine oil (made by Showa Shell Sekiyu KK)
Organic peroxide: Park mill D-40 (manufactured by NOF Corporation)
・ Sulfur: Powdered sulfur (manufactured by Karuizawa Refinery)

As is apparent from the results shown in Table 1, ethylene bis (pentabromobenzene) and a sulfur-containing silane cup containing the flame retardant aluminum hydroxide, decabromodiphenyl ether and ammonium polyphosphate described in Patent Document 1 It was found that the rubber composition of Comparative Example 2 prepared without blending the ring agent was inferior in rubber flowability during vulcanization, as a result, the appearance after vulcanization was slightly inferior, and the workability during demolding was inferior. .
On the other hand, instead of decabromodiphenyl ether, the rubber compositions of Examples 1 to 4 prepared by blending ethylene bis (pentabromobenzene) and further blending a sulfur-containing silane coupling agent were It was found that the same level of excellent flame retardancy was maintained, and the appearance after vulcanization and workability during demolding were excellent.
On the other hand, even when ethylene bis (pentabromobenzene) and a sulfur-containing silane coupling agent are blended, the rubber composition of Comparative Example 3 with a large amount of silica is inferior in rubber flowability during vulcanization. It was found that the appearance after vulcanization was inferior and the workability during demolding was slightly inferior.
Further, in Comparative Example 4 in which vinyltriethoxysilane was blended instead of the sulfur-containing silane coupling agent, as in Comparative Example 2, as a result of inferior rubber flowability during vulcanization, the appearance after vulcanization was slightly inferior, It was found that the workability during demolding was inferior.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Outer hood 3 Straight member 4, 4 ', 4 "Shoulder member 5 Passage 6 Flexible film body 7 Center vicinity 8 Flange part 9 Through-hole 10 Outer surface 11 Curved part 12 Outer hood (protective rubber)

Claims (3)

  Silica 20 to 40 parts by mass, silicate mineral 10 to 50 parts by mass, aluminum hydroxide 30 to 80 parts by mass, and ethylene bis (pentabromobenzene) 20 with respect to 100 parts by mass of the ethylene-propylene copolymer. A rubber composition containing -50 parts by mass, 5-30 parts by mass of ammonium polyphosphate, and 0.5-5.0 parts by mass of a sulfur-containing silane coupling agent.   The rubber composition according to claim 1, which is a rubber composition for an outer hood of a railway vehicle.   An outer hood for a railway vehicle using the rubber composition according to claim 1 as a material.