JP2008274252A - Rubber composition for outer hood, and outer hood for railway vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for an external hood that is excellent in breaking elongation and wear resistance. <P>SOLUTION: The rubber composition for an external hood comprises 40-80 pts.mass titanium oxide, 10-30 pts.mass silica and 0.5-3.0 pts.mass diethylene glycol, each based on 100 pts.mass EPDM. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

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 railway vehicles include, for example, a hardness that does not buckle even if a person leans on it, excellent weather resistance, and white or gray rubber products. The rubber flow during vulcanization is good.
The present applicant has previously proposed Patent Document 1 as a rubber composition capable of providing a white or colored rubber product.
Patent Document 1 discloses a white filler containing 1 to 15 parts by weight of an organic peroxide and 20% by weight or more of silica with respect to 100 parts by weight of at least one ethylene-propylene copolymer selected from the group consisting of EPDM and EPM. A rubber composition characterized by containing 50 to 200 parts by weight and 0.3 to 5 parts by weight of a silane coupling agent containing a sulfur atom in the molecule is described.

Japanese Patent Laid-Open No. 2002-265714

However, the present inventor has found that the rubber obtained from the rubber composition described in Patent Document 1 has room for improvement in breaking elongation as an outer hood for a railway vehicle.
In addition, a new problem has arisen in that an outer hood for a railway vehicle obtained from a rubber composition containing talc is likely to damage the outer hood due to the collision or wear of the outer hoods and the outer hood is easily damaged.
Then, an object of this invention is to provide the rubber composition for outer hoods which is excellent in elongation at break and abrasion resistance.
Another object of the present invention is to provide an outer hood for a railway vehicle that is excellent in elongation at break and wear resistance.

  As a result of diligent research to solve the above problems, the present inventor has a rubber composition containing a specific amount of titanium oxide, silica, and diethylene glycol with respect to EPDM, which is excellent in elongation at break and wear resistance. The present invention was completed by finding out that it could be an outer hood for a railway vehicle.

That is, the present invention provides the following (1) to (4).
(1) A rubber composition for an outer hood containing 40 to 80 parts by mass of titanium oxide, 10 to 30 parts by mass of silica, and 0.5 to 3.0 parts by mass of diethylene glycol with respect to 100 parts by mass of EPDM.
(2) The rubber composition for an outer hood as described in (1) above, which does not substantially contain a silane coupling agent.
(3) The rubber composition for an outer hood according to (1) or (2), further including 1 to 10 parts by mass of an organic peroxide and 0.05 to 1.0 part by mass of sulfur.
(4) An outer hood for a railway vehicle using the rubber composition for an outer hood as described in any one of (1) to (3) as a material.
The present invention further provides the following (5) to (7).
(5) The rubber composition for an outer hood according to the above (1) or (2), further comprising sulfur and a vulcanization accelerator or an organic peroxide.
(6) The outer hood rubber according to (5), wherein the amount of sulfur is 0.5 to 3.0 parts by mass and the amount of the vulcanization accelerator is 1.0 to 3.0 parts by mass. Composition.
(7) An outer hood for a railway vehicle using the rubber composition for an outer hood as described in (5) or (6) above as a material.

The rubber composition for an outer hood of the present invention can be an outer hood for a railway vehicle having excellent elongation at break and wear resistance.
The outer hood for a railway vehicle of the present invention is excellent in breaking elongation and wear resistance.

The present invention will be described in detail below.
The rubber composition for an outer hood of the present invention contains 40 to 80 parts by mass of titanium oxide, 10 to 30 parts by mass of silica, and 0.5 to 3.0 parts by mass of diethylene glycol with respect to 100 parts by mass of EPDM. It is.

EPDM will be described below.
The EPDM contained in the rubber composition for an outer hood of the present invention is not particularly limited as long as it is a copolymer obtained from ethylene, propylene and a diene monomer.
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 excellent processability.

The iodine value of EPDM is preferably 3 to 25 and more preferably 3 to 20 from the viewpoint of excellent chemical resistance and weather resistance.
The ethylene content in EPDM is preferably 90 to 40 mol%, more preferably 80 to 50 mol%, from the viewpoint of excellent vulcanization properties such as elongation at break.
Further, the Mooney viscosity of EPDM at 100 ° C. is preferably 30 to 80, more preferably 50 to 70, from the viewpoint of excellent processability.
EPDM can be used alone or in combination of two or more.
EPDM is not particularly limited for its production. For example, a conventionally well-known thing is mentioned.

Titanium oxide will be described below.
The titanium oxide contained in the outer hood rubber composition of the present invention is not particularly limited.
The amount of titanium oxide is high in elongation at break, excellent in abrasion resistance, excellent in weather resistance, rubber flowability during vulcanization, and has a hardness that can prevent falling from the station platform, and is white or gray. From the viewpoint of being able to be a rubber such as, it is 40 to 80 parts by mass with respect to 100 parts by mass of EPDM.
In addition, the amount of titanium oxide is higher in elongation at break and excellent in wear resistance, excellent in weather resistance, rubber flowability during vulcanization, and has a hardness that can serve to prevent falling from the platform of the station, From the viewpoint that the rubber can be white or gray, it is preferably 40 to 70 parts by mass, more preferably 45 to 65 parts by mass with respect to 100 parts by mass of EPDM.

Silica will be described below.
The silica contained in the outer hood rubber composition of the present invention is not particularly limited. Examples thereof include hydrous silica, anhydrous silica, precipitated silica, and fumed silica.
The amount of silica is high in elongation at break, excellent in abrasion resistance, excellent in weather resistance, rubber flowability during vulcanization, and has a hardness that can serve to prevent falling from the station platform, such as white or gray From the viewpoint of being able to be a rubber, it is 10 to 30 parts by mass with respect to 100 parts by mass of EPDM.
In addition, the amount of silica is higher in breaking elongation, better in wear resistance, excellent in weather resistance, rubber flowability during vulcanization, and has a hardness that can serve as a fall prevention function from the station platform. Or from a viewpoint that it can become rubbers, such as gray, it is preferred that it is 10-25 mass parts to 100 mass parts of EPDM.
Silica can be used alone or in combination of two or more.

Diethylene glycol will be described below.
The diethylene glycol contained in the outer hood rubber composition of the present invention is not particularly limited.
By containing diethylene glycol, the rubber composition for outer hood of the present invention has high elongation at break, excellent wear resistance, excellent weather resistance, rubber flowability during vulcanization, and a function to prevent falling from the platform of the station. It can be a rubber having a hardness that can be achieved.

The amount of diethylene glycol is 0.5 to 3.0 parts by mass with respect to 100 parts by mass of EPDM. In such a range, it can be a rubber having a high elongation at break, excellent wear resistance, excellent weather resistance, rubber flowability during vulcanization, and a hardness sufficient to perform a function of preventing falling from a station platform.
In addition, the amount of diethylene glycol can be a rubber having higher elongation at break, better wear resistance, better weather resistance, better rubber flow during vulcanization, and a hardness that can serve to prevent falling from the station platform. In view of the above, it is preferably 0.5 to 2.5 parts by mass, more preferably 0.5 to 2.0 parts by mass with respect to 100 parts by mass of EPDM.

The rubber composition for an outer hood of the present invention can further contain an organic peroxide.
The organic peroxide that can be further contained in the rubber composition for an outer hood of the present invention is not particularly limited as long as it is used for rubber peroxide vulcanization.
Examples thereof include dicumyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, benzoyl peroxide, and 1,3-bis (t-butylperoxyisopropyl) benzene.
Of these, dicumyl peroxide is preferable from the viewpoint of excellent crosslinking effect.
An organic peroxide can be used individually or in combination of 2 types or more, respectively.

  The amount of the organic peroxide is preferably 1 to 10 parts by mass and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of EPDM. When the amount of the organic peroxide is 1 part by mass or more, the number of crosslinking points increases and the physical properties are excellent. Moreover, when the amount of the organic peroxide is 10 parts by mass or less, the organic peroxide residue is small and the heat aging is hardly affected.

Examples of the co-crosslinking agent that can be used in combination with the organic peroxide include trimethylolpropane trimethacrylate, tri (2-ethylhexyl) trimethacrylate, and triallyl isocyanate.
The amount of the co-crosslinking agent is preferably 1 to 30 parts by mass with respect to 100 parts by mass of EPDM.

Moreover, the rubber composition for outer hoods of this invention can contain sulfur further.
The sulfur that the rubber composition for an outer hood of the present invention can further contain is not particularly limited as long as it is used for rubber vulcanization.

The amount of sulfur is preferably 0.05 to 3.0 parts by mass and more preferably 1.0 to 3.0 parts by mass with respect to 100 parts by mass of EPDM.
In the present invention, sulfur can be used as a vulcanizing agent or a vulcanization aid. In the present invention, when sulfur is used as a vulcanizing agent, it is preferable to use a vulcanization accelerator in combination. Moreover, when using an organic peroxide in this invention, it is preferable to use sulfur together as a vulcanization auxiliary.

The amount of sulfur is preferably 0.05 to 1.0 part by mass and more preferably 0.05 to 0.5 part by mass with respect to 100 parts by mass of EPDM. When the amount of sulfur is 0.05 parts by mass or more, vulcanized physical properties such as elongation at break are excellent. Moreover, when the amount of sulfur is 1.0 part by mass or less, the wear resistance and heat resistance are excellent.
The amount of sulfur described above is for use in combination with an organic peroxide.
In the present invention, sulfur is used as a vulcanization aid, and when organic peroxide is used as a crosslinking agent, it acts to suppress molecular cutting of rubber during a crosslinking reaction that is likely to occur in crosslinking with organic peroxide. Conceivable.
When using sulfur as a vulcanizing agent, the amount of sulfur is preferably 0.5 to 3.0 parts by mass, more preferably 1.0 to 2.5 parts by mass with respect to 100 parts by mass of EPDM. Preferably, it is 1.3-2.5 mass parts. When the amount of sulfur is 0.5 parts by mass or more, vulcanized physical properties such as hardness and abrasion resistance are excellent. Moreover, when the amount of sulfur is 3.0 parts by mass or less, the heat resistance and elongation at break are excellent.

  The vulcanization accelerator that the rubber composition for an outer hood of the present invention can further contain is not particularly limited as long as it is used for rubber vulcanization. For example, inorganic vulcanization accelerators such as slaked lime, magnesia (MgO), and resurge (PbO); and organic vulcanization accelerators.

Examples of organic vulcanization accelerators include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole and N-cyclohexyl-2-benzothiazolesulfene; fats such as n-butylamine, tert-butylamine and propylamine. Oxidative condensates of aliphatic primary amines with 2-mercaptobenzothiazole, oxidative condensates of aliphatic secondary amines such as dicyclohexylamine, pyrrolidine and piperidine with 2-mercaptobenzothiazole, alicyclic primary amines and 2 -Sulfenamide vulcanization accelerators such as oxidative condensate with mercaptobenzothiazole, oxidative condensate between morpholine compound and 2-mercaptobenzothiazole; tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD) ), Tetraethylthiu Thiuram-based vulcanization accelerators such as mudimonosulfide (TETD), tetrabutylthiuram dimonosulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT); zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC) And dithiocarbamate vulcanization accelerators such as zinc di-n-butylcarbamate (ZnBDC).
Vulcanization accelerators can be used alone or in combination of two or more.

Examples of the combination of the vulcanization accelerator include a combination of a sulfenamide vulcanization accelerator and a thiuram vulcanization accelerator, a dithiocarbamate vulcanization accelerator, a thiazole vulcanization accelerator and a thiuram vulcanization. A combination with an accelerator may be mentioned.
A combination of a sulfenamide vulcanization accelerator and a thiuram vulcanization accelerator, a dithiocarbamate vulcanization accelerator, a thiazole vulcanization accelerator, and a thiuram vulcanization accelerator from the viewpoint of superior elongation at break and abrasion resistance. A combination with a sulfur accelerator is preferred.

  In the present invention, the amount of the vulcanization accelerator is preferably 1.0 to 3.0 parts by mass with respect to 100 parts by mass of EPDM, from the viewpoint of being excellent in elongation at break and abrasion resistance. More preferably, it is 3.0 parts by mass.

  The rubber composition for an outer hood according to the present invention preferably contains sulfur and a vulcanization accelerator or an organic peroxide from the viewpoint of excellent elongation at break and wear resistance. It is more preferable to contain.

  When the rubber composition for an outer hood according to the present invention contains sulfur and a vulcanization accelerator, the amount of sulfur is 0.5 to 3 with respect to 100 parts by mass of EPDM from the viewpoint of being excellent in elongation at break and wear resistance. It is preferably 0.0 parts by mass, more preferably 1.0 to 2.5 parts by mass, and even more preferably 1.3 to 2.5 parts by mass.

  Further, when the outer hood rubber composition of the present invention contains sulfur and a vulcanization accelerator, the amount of the vulcanization accelerator is 100 parts by mass of EPDM from the viewpoint of being excellent in elongation at break and wear resistance. It is preferably 1.0 to 3.0 parts by mass, and more preferably 1.5 to 3.0 parts by mass.

  When the outer hood rubber composition of the present invention contains an organic peroxide and sulfur, the amount of the organic peroxide is preferably 1 to 10 parts by mass with respect to 100 parts by mass of EPDM. More preferably, it is 10 parts by mass. When the amount of the organic peroxide is 1 part by mass or more, the number of crosslinking points increases and the physical properties are excellent. Moreover, when the amount of the organic peroxide is 10 parts by mass or less, the organic peroxide residue is small and the heat aging is hardly affected.

  Further, when the rubber composition for an outer hood of the present invention contains an organic peroxide and sulfur, the amount of sulfur is preferably 0.05 to 1.0 part by mass with respect to 100 parts by mass of EPDM. It is more preferable that it is 0.05-0.5 mass part. When the amount of sulfur is 0.05 parts by mass or more, vulcanized physical properties such as elongation at break are excellent. Moreover, when the amount of sulfur is 1.0 part by mass or less, the wear resistance and heat resistance are excellent.

  In addition to EPDM, titanium oxide, silica, diethylene glycol, organic peroxide or vulcanization accelerator and sulfur, the rubber composition for the outer hood of the present invention includes, for example, a filler other than titanium oxide and silica, if necessary. Contains additives such as organic sulfur-containing compounds such as N, N-dithiobismorpholine, plasticizers, pigments, vulcanization aids, vulcanization accelerators, vulcanization accelerators, anti-aging agents, etc. can do.

  Fillers other than titanium oxide and silica are not particularly limited. Examples thereof include carbon black, heavy calcium carbonate, surface-treated calcium carbonate, zinc oxide, magnesium oxide, diatomaceous earth, precipitated barium sulfate, hydrous silicate, fine particle carbonate, hard clay, and talc.

The plasticizer can be used to ensure the dispersibility of the filler. As a plasticizer, a process oil and a liquid polymer are mentioned, for example, These can also be mixed and used.
Examples of the process oil as the plasticizer include paraffinic, naphthenic and aromatic oils. In view of fracture characteristics and compatibility with EPDM, paraffinic compounds are particularly preferable in order to avoid deterioration of physical properties.

  Examples of the liquid polymer as the plasticizer include liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid EPDM, and liquid EPM. In particular, in view of compatibility with EPDM, in order to avoid deterioration of physical properties, it is preferable to use liquid EPDM or liquid EPM as a plasticizer.

A pigment can be used for coloring the outer hood rubber composition of the present invention. Examples of the pigment include inorganic pigments and organic pigments, which can be used in combination.
Examples of the inorganic pigment include titanium dioxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, and the like.
Examples of organic pigments include azo pigments, phthalocyanine pigments, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, perinone pigments, diketopyrrolopyrrole. Examples thereof include pigments, quinonaphthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindoline pigments, and carbon black.
The pigments can be used alone or in combination of two or more.
What is necessary is just to determine the quantity of a pigment suitably as needed, and 0.1-2 mass parts can be added with respect to 100 mass parts of EPDM.

Examples of the vulcanization aid include fatty acids such as acetyl acid, propionic acid, butanoic acid, stearic acid, acrylic acid, and maleic acid; zinc acetylate, zinc propionate, zinc butanoate, zinc stearate, zinc acrylate, Examples include fatty acid zinc such as zinc maleate.
Examples of the vulcanization accelerator include thiurams such as tetramethylthiuram disulfide (TMTD) and tetraethylthiuram disulfide (TETD); aldehydes and ammonia such as hexamethylenetetramine; guanidines such as diphenylguanidine: dibenzothiazyl disulfide (DM) and the like; sulfenamides such as cyclohexylbenzothiazylsulfenamide and the like. Further, an alkylphenol resin or a halide thereof may be used.
As the vulcanization acceleration aid, for example, metal compounds such as zinc white, and fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid can be used.

  Examples of the anti-aging agent include ketone / amine condensates such as TMDQ, amines such as DNPD, monophenols such as styrenated phenol, and the like.

The rubber composition for an outer hood of the present invention is substantially free from a silane coupling agent from the viewpoint that it is excellent in elongation at break and stable product characteristics can be obtained without deactivating the organic peroxide. Is preferred. When a silane coupling agent is contained, examples of the silane coupling agent that can be used include vinyl silane.
The amount of the silane coupling agent is preferably 0.1 to 0.3 parts by mass with respect to 100 parts by mass of EPDM from the viewpoint of not reducing elongation at break.
In the present invention, “substantially not containing a silane coupling agent” means that the amount of the silane coupling agent is 0.3 parts by mass or less with respect to 100 parts by mass of EPDM.
Moreover, when using sulfur as a vulcanizing agent in this invention, the rubber composition for outer hoods of this invention can contain a silane coupling agent further.

The rubber composition for an outer hood of the present invention is not particularly limited for its production. For example, EPDM, titanium oxide, silica and diethylene glycol, an organic peroxide or a vulcanization accelerator and sulfur, and an additive that can be used as necessary, using a roll mill or a closed mixer, The rubber composition for an outer hood of the present invention can be obtained by uniformly dispersing and mixing.
Also, for example, EPDM, titanium oxide, silica, and diethylene glycol and additives that can be used as necessary are uniformly dispersed, mixed, and vulcanized using a roll mill or a closed mixer. The rubber composition for an outer hood of the present invention can be obtained by adding an organic peroxide or a vulcanization accelerator and sulfur to the mixture and uniformly dispersing and mixing the mixture using a closed mixer or the like.
The resulting rubber composition is excellent in rubber flow during vulcanization and can secure sufficient tensile strength after vulcanization, so the molding method is usually molding of rubber products such as injection molding, blow molding, press molding, extrusion molding, etc. Molding and vulcanization can be performed by a method used for processing.

The rubber composition for the outer hood of the present invention has a long Mooney scorch time, and since the rubber does not burn for a long time when working on a hot plate during molding, the processing safety is high and the vulcanization speed does not decrease, so the productivity is high. Is excellent.
The vulcanizate obtained from the rubber composition for an outer hood according to the present invention has a high elongation at break, excellent wear resistance, weather resistance, and tensile strength, and has a hardness (JIS) that can serve to prevent falling from a station platform. Hardness: 57-67).
Further, the color of the vulcanizate obtained from the rubber composition for an outer hood of the present invention is not particularly limited, but white and gray can be mentioned from the viewpoint of improving the aesthetic appearance according to the color scheme of the railway vehicle.

Next, the outer hood for a railway vehicle of the present invention will be described below.
The outer hood for a railway vehicle of the present invention is not particularly limited as long as the rubber composition for the outer hood of the present invention is used as a material.

  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 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 is used by covering the woven fabric made of fibers of nylon, aramid, PET, etc. with the rubber composition for an outer hood of the present invention as a reinforcing layer in order to increase rigidity and resilience as required. can do.

In FIG. 2, the outer shapes of the vehicle 21 and the outer hood 23 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 membrane 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 21. .
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 linear member 3 and attaching it to the vehicle 1 with the longitudinal end of the shoulder member 4 overlapped with the end of the linear 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, only the two left and right linear members 3 may be used, and the linear members may be flat.

The inventor of the present application considered that an outer hood for a railway vehicle obtained from a conventional rubber composition for an outer hood containing talc is inferior in wear resistance because the talc peels off due to friction.
On the other hand, the outer hood for a railway vehicle of the present invention is excellent in elongation at break and wear resistance.
This is because the rubber composition for an outer hood used for the outer hood for a railway vehicle of the present invention contains diethylene glycol, thereby preventing silica from aggregating in EPDM and effectively dispersing silica in EPDM. By increasing the reaction point between silica and EPDM, it is considered that silica and EPDM are bonded to each other, so that the wear resistance is increased without reducing the breaking elongation of the resulting rubber.
In addition, said mechanism is a presumption of this inventor, and even if it is other than said mechanism, it is in the range of this invention.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

1. Evaluation The obtained rubber composition was subjected to the following tests to evaluate its unvulcanized or vulcanized rubber properties. The results are shown in Tables 1 and 2.
(1) Mooney scorch test Based on the Mooney scorch test method of JIS K6300-1: 2001, the Mooney viscometer (L-shaped rotor) was used to measure the Mooney minimum viscosity (min torque) and Mooney scorch time at 125 ° C. . As for the Mooney scorch time, the time (ML5up, unit: minute) required to increase by 5 Mooney from the min torque is displayed.

(2) Rotorless rheometer test In accordance with a vulcanization test of JIS K6300-2: 2001, a rotorless rheometer was used to measure stress by applying vibration to rubber to obtain a vulcanization curve. A time T ₉₅ [min] until reaching a stress corresponding to 95% of the difference between the maximum value and the minimum value of the obtained stress at a vulcanization temperature of 160 ° C. was determined. The larger the vulcanization rate of T ₉₅ is slow.

(3) Tensile test The obtained rubber composition was subjected to press vulcanization at 160 ° C for 60 minutes, molded into JIS standard No. 3 dumbbell (JIS K6251: 2004), and tensioned according to JIS K6251: 2004. Strength (T _B ) and elongation at break (E _B ) were measured.
When the tensile strength is 6.9 MPa or more, it is practical as an outer hood for a railway vehicle.
When the elongation at cutting is 400% or more, it is practical as an outer hood for a railway vehicle.

(4) JIS hardness: According to JIS K 6253: 2006, the hardness at 23 ° C. was measured using a spring type A type hardness tester.
When the JIS hardness is 57 to 67, it is practical as an outer hood for a railway vehicle.

(5) DIN abrasion test The obtained rubber composition was press vulcanized at 160 ° C for 60 minutes, and in accordance with the DIN abrasion test method described in JIS K6264-2: 2005, the abrasion distance was 9.8 N at a load of 40 rpm. The amount of wear (mm ³ ) after 40 m was measured.
When the wear loss is within 185 mm ³ , it is practical as an outer hood for a railway vehicle.

2. Preparation of rubber composition The components (excluding organic peroxide and sulfur) shown in Table 1 in the blending amounts (parts by mass) shown in Table 1 were charged into 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.

Each component shown in Table 1 is as follows.
・ EPDM: ESPRENE305 (manufactured by Sumitomo Chemical Co., Ltd.)
・ SiO ₂ : Nip seal VN3 (made by Nippon Silica)
・ TiO ₂ : R-650 (manufactured by Sakai Chemical Industry Co., Ltd.)
-Talc: N talc (made by Nippon Talc)
Aluminum hydroxide: Heidilite H-42M (Showa Denko)
Diethylene glycol: manufactured by Maruzen Petrochemical Co., Ltd. Silane coupling agent: vinyl-tris (2-methoxy-ethoxy) silane (trade name A-172, manufactured by Nihon Unicar)
Organic peroxide: Park mill D-40 (manufactured by NOF Corporation)
・ Sulfur: Powdered sulfur (manufactured by Karuizawa Refinery)

As is clear from the results shown in Table 1, Comparative Examples 3 and 4 containing fillers other than titanium oxide and silica were inferior in wear resistance.
Further, Comparative Example 1 not containing diethylene glycol and Comparative Example 2 not containing silica had low elongation at break and poor wear resistance.
On the other hand, Examples 1-7 have high elongation at break and excellent wear resistance.

3. Preparation of rubber composition The components (excluding sulfur and vulcanization accelerator) shown in Table 2 in the blending amounts (parts by mass) shown in Table 2 were charged into a 20 L kneader mixer and mixed for about 15 minutes. Thereafter, the obtained rubber mixture was wound around an 18-inch kneading roll, sulfur and vulcanization accelerators 1 to 4 were added, and kneaded for about 10 minutes to obtain a rubber composition.

Each component other than the vulcanization accelerators 1 to 4 shown in Table 2 is the same as that shown in Table 1.
The details of the vulcanization accelerators 1 to 4 are as follows.
・ Vulcanization accelerator 1: Vulcanization accelerator CZ (sulfenamide vulcanization accelerator), manufactured by Ouchi Shinsei Chemical Co., Ltd. ・ Vulcanization accelerator 2: Vulcanization accelerator BZ (dithiocarbamate vulcanization accelerator) Agent), made by Ouchi Shinsei Chemical Co., Ltd., vulcanization accelerator 3: vulcanization accelerator M (thiazole vulcanization accelerator), made by Sanshin Chemical Industry Co., Ltd., vulcanization accelerator 4: vulcanization accelerator TS ( Thiuram vulcanization accelerator), manufactured by Sanshin Chemical Industry Co., Ltd.

As is apparent from the results shown in Table 2, Examples 8 and 9 containing sulfur and a vulcanization accelerator have a high elongation at break and excellent wear resistance.
In addition, Examples 8 and 9 are more excellent in abrasion resistance than Examples 1 to 7.

It is a typical partial perspective view for demonstrating one Embodiment with the outer hood of this invention attached to the vehicle. It is the sectional view on the AA line of FIG. 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 Vehicle 2, 23 Outer hood 3 Straight member 4 Shoulder member 5 Passage 6 Flexible film body 7 Near center 8 Flange part 9 Through hole

Claims (6)

  A rubber composition for an outer hood containing 40 to 80 parts by mass of titanium oxide, 10 to 30 parts by mass of silica, and 0.5 to 3.0 parts by mass of diethylene glycol with respect to 100 parts by mass of EPDM.   The rubber composition for an outer hood according to claim 1, further comprising sulfur and a vulcanization accelerator or an organic peroxide.   The rubber composition for an outer hood according to claim 2, wherein the amount of sulfur is 0.5 to 3.0 parts by mass, and the amount of the vulcanization accelerator is 1.0 to 3.0 parts by mass.   The rubber composition for an outer hood according to claim 2, containing 1 to 10 parts by mass of the organic peroxide and 0.05 to 1.0 part by mass of the sulfur.   The rubber composition for an outer hood according to any one of claims 1 to 4, which does not substantially contain a silane coupling agent.   An outer hood for a railway vehicle using the rubber composition for an outer hood according to any one of claims 1 to 5 as a material.

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