DE102016217333A1 - Articles, in particular a metal-rubber element for rail vehicles - Google Patents

Abstract

The invention relates to an article having a base body made of a polymeric material having elastic properties, in particular a metal-rubber element for rail vehicles. The article, in particular the metal-rubber element, has a base body made of a polymeric material having elastic properties for improving the fire-retardant properties, wherein the base body of the base body has an article surface which is completely or partially provided with at least one coating, wherein the coating is formed from at least one rubber mixture and wherein the rubber mixture of the coating contains at least one flame retardant or is flame retardant by itself.

Description

The invention relates to an article having a base body made of a polymeric material having elastic properties, in particular a metal-rubber element for rail vehicles.

Rail vehicles have metal-rubber elements in various designs as suspension systems that contribute significantly to the comfort and safety of rail vehicles. These suspension systems have not only suspension, but also leadership and damping tasks. They can be found, inter alia, in the primary spring area between wheelsets and bogies and take over there predominantly the wheelset. In the secondary spring range between bogie and car body, the metal-rubber elements serve as elastic mounting of the car body, often in combination with an air spring bellows. They decouple it largely from the irregularities of the track system and reduce the transmission of structure-borne noise. At the same time they allow the turning of the bogie in Bogenfahrt.

These articles, which are used for suspension of, for example, motor vehicles or railway vehicles and / or serve for vibration damping, are manufactured using elastomeric mixtures, also referred to as rubber compounds. These elastomeric blends commonly used for the basic properties of such articles are well known. Articles having excellent elastic properties, such as metal-rubber elements or vibration dampers, preferably contain vulcanized rubber compounds predominantly based on natural rubber (NR) and / or polyisoprene rubber (IR). However, articles with these elastomeric mixtures show significant disadvantages in the fire behavior. In case of fire, dense flue gases are produced. In the combustion process of said elastomeric mixtures, which are predominantly based on NR and / or IR, the heat release rate is particularly high.

Due to the increased requirements in recent years in terms of fire protection, which is mainly in the tightened fire safety standard EN45545 show, there is an increased demand for fire-optimized polymer articles. These fire protection requirements, the elastomeric mixtures based mainly on NR and / or IR, especially due to the required maximum heat release rate, no longer meet. Thus, the articles containing these elastomeric blends usually no longer meet the stringent requirements.

A common method to improve the fire behavior of rubber compounds is the direct incorporation of fire-retardant substances. However, in the case of the articles concerned, this measure generally leads to a significant deterioration in the physical properties, in particular the suspension, setting or vibration properties.

In WO 2014/019008 A1 In order to solve this problem, it is proposed to use an exclusively sulfur-crosslinked additional outer layer containing a vinyl acetate-containing thermoplastic polymer, a double bond-containing unsaturated elastomer and at least one flame retardant. This additional outer layer must be vulcanized onto the component or onto the basic body of the component at comparatively high vulcanization temperatures via a specifically controlled vulcanization process. In WO 2014 / 019008A1 Thus, if necessary, a vulcanization process must be carried out twice in succession. This not only means a higher production-related effort, but the two-fold vulcanization can also lead to unwanted and harmful reversion processes in the already vulcanized polymer mixture located under the outer layer. Polymer blends which are predominantly based on NR and / or IR show significant reversion processes on overvulcanization.

Out WO 2016 / 045813A1 is particularly known for air springs overcome these disadvantages by a coating of a textile or a shrink film. It has been found, however, that such a textile coating or the coating of a shrink film leads to a significant overhead in the production, since these additional materials not only purchased or even expensive to manufacture themselves, but must also be stored and processed. As a rule, the textile coating also has to be adhesively bonded to the main body and thus can not be removed or replaced without causing damage to the article.

The object of the invention is now to provide an article, in particular a metal-rubber element, which is characterized by an optimized fire protection performance to meet the more stringent requirements, in particular those in EN45545 described to fulfill. At the same time, the necessary physical properties of the article should remain at a comparable level and the complexity in the production process should not be appreciably increased.

At the same time, the present invention is intended to provide a simpler alternative on a production scale. especially for metal-rubber elements, to which in WO 2016 / 045813A1 offer the solution described.

This object is achieved in that the article having a base body made of a polymeric material having elastic properties, in particular the metal-rubber element, an article surface which is completely or partially provided with at least one coating, wherein the coating of at least one rubber mixture is formed and wherein the rubber mixture of the coating contains at least one flame retardant or is flame retardant by itself.

As a cover, according to Duden an interchangeable cover or an exchangeable sleeve is called, which protects something.

In the context of the present invention, the coating protects the underlying article from direct heat radiation, so that the combination of coating and base body meets the requirements of EN45545 , in particular the requirements of EN45545-2 , enough.

The coating here consists of at least one rubber mixture which contains at least one flame retardant or of a rubber mixture which is inherently fire retardant, i. which does not require any additional flame retardants due to a suitable choice for the individual blend ingredients to meet the above requirements.

Partially means in this context that only certain, defined areas or sections of the article surface of the entire article are provided with a coating.

In order to prevent the coating from slipping off, the coating is fastened to the article at defined locations by means of a special connection arrangement such that it can be detached again at any time without damaging the article. This may, for example, be advantageous for a visual inspection of the article or else for a replacement of the coating in the event of damage.

In a preferred embodiment, there is a releasable positive connection between the coating and the base body, so that no additional connecting elements are required. No tools are needed for this type of connection. In particular, for high-speed applications, but it is also a screw and / or clamp connection alone or in combination conceivable, for. Eg via a hose clamp or a direct screw connection.

The coating is in this case formed according to the specifications of the article, i. is adapted to the outer shape of the article.

The cover is thus in no immediate connection with the article surface.

With the exception of the joints between the coating and the article surface is an air layer, which may optionally serve as an additional insulation layer in case of fire.

The article and the cover are thus freely movable to each other and due to the lack of contact also no abrasion takes place.

The geometry of the coating can be freely designed to better meet any space requirements. Thus, for example, a connection between the coating and bogie component of the rail vehicle is conceivable, should the space be insufficient.

The formation of such an air layer is covered with a coating, as in WO 2016 / 045813A1 is described, even without adhesive bond between the coating described there and the article surface, not possible.

The inventive coating of at least one rubber mixture, it is possible that the main body can continue to be built up from the previously used rubber compound and thus continue to take over the majority of the spring properties for which a mechanically highly stressed material is essential. The coating then takes over the fire protection, so to speak, and plays no or only a subordinate role for the wearing properties. The coating protects the surface of the metal-rubber part exposed in the installation area. For this purpose, the coating may extend to the entire article, so that the main body is completely covered by the coating or the coating is only located on certain exposed areas of the metal-rubber element, which are particularly prone to fire.

According to §4.3.4 of EN45545-2: 2016 it is possible that small, unprotected areas up to 0.2m ^{2 are allowed} under certain circumstances.

In an advantageous embodiment, the coating may additionally be provided with a reflective and / or heat-insulating coating or with a flame-retardant flock. As a result, the thickness of the actual coating can be further reduced.

The main body is constructed from a rubber mixture, preferably thermoplastic free is, containing at least one rubber component and other Mischingingredienzien. Rubber components which may be mentioned in particular are: ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), (partially) hydrogenated nitrile rubber (HNBR), fluorinated rubber (FKM), chloroprene rubber. Rubber (CR), Natural Rubber (NR), Deproteinized Natural Rubber (DPNR), Epoxidized Natural Rubber (ENR), Styrene Butadiene Rubber (SBR), Isoprene Rubber (IR), Butyl Rubber (IIR), Bromobutyl Rubber (BIIR), Chlorobutyl Rubber ( CIIR), brominated copolymer of isobutylene and paramethylstyrene (BIMS), polyepichlorohydrin rubbers (CO, ECO, ETER), butadiene rubber (BR), chlorinated polyethylene (CM) alkylated chlorosulfonated polyethylene (ACSM), and / or chlorosulfonated polyethylene (CSM).

The aforementioned types of rubber may be unblended. The use of a blend, in particular in conjunction with one of the abovementioned types of rubber, for example a CR / NR blend, (A) CSM / NR blend, NR / IR blend, NR / BR blend or a BR / SBR blend , is possible.

For the reasons already mentioned, preference is given to using NR and / or IR as the rubber component for a metal-rubber element.

The usual compounding ingredients include at least one crosslinker or crosslinker system (crosslinker and accelerator). Additional compounding ingredients are usually at least one filler and / or at least one processing aid and / or at least one plasticizer and / or at least one aging inhibitor and optionally further additives (for example color pigments, reinforcing fibers). In this regard, reference is made to the general state of rubber mixing technology.

According to the invention, the coating consists of at least one rubber mixture which is preferably thermoplastic-free, containing at least one rubber component as well as further mixture ingredients. Rubber components which may be mentioned in particular are: ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), nitrile rubber (NBR), (partially) hydrogenated nitrile rubber (HNBR), fluorinated rubber (FKM), chloroprene rubber. Rubber (CR), Natural Rubber (NR), Deproteinized Natural Rubber (DPNR), Epoxidized Natural Rubber (ENR), Styrene Butadiene Rubber (SBR), Isoprene Rubber (IR), Butyl Rubber (IIR), Bromobutyl Rubber (BIIR), Chlorobutyl Rubber ( CIIR), brominated copolymer of isobutylene and paramethylstyrene (BIMS), butadiene rubber (BR), polyepichlorohydrin rubbers (CO, ECO, ETER) and / or chlorinated polyethylene (CM) and / or chlorosulfonated polyethylene (CSM) and / or alkylated chlorosulfonated polyethylene (ACSM) and / or silicone rubber (MQ, VMQ, PVMQ, FVMQ) and / or fluorinated methyl silicone rubber (MFQ) and / or perfluorinated propylene rubber (FFPM) and / or perfluorocarbon rubber (FFKM) and / or polyurethane (PU) ,

The aforementioned types of rubber may be unblended. The use of a blend, in particular in conjunction with one of the abovementioned types of rubber, for example, a (A) CSM / NR blend, (A) CSM / CR blend, CR / NR blend, NR / IR blend, NR / BR -Verschnitt or a BR / SBR blend, is possible.

However, preference is given to using EPDM and / or CSM and / or ACSM as rubber components for the coating.

CSM inherently has excellent flame retardant properties and high resistance to environmental and aggressive media. When using CSM, it may be necessary to dispense with a flame retardant. In addition to the advantages of CSM, ACSM also has significantly improved cold flexibility.

In addition to good ozone, aging and heat resistance, EPDM has a favorable processing behavior, is inexpensive and stable against many polar solvents.

The usual compounding ingredients include at least one crosslinker or crosslinker system (crosslinker and accelerator). Additional mixture ingredients are usually still a filler and / or a processing aid and / or a plasticizer and / or an anti-aging agent and optionally other additives, such. Color pigments, reinforcing fibers.

In this regard, reference is made to the general state of rubber mixing technology.

In particular, the use of reinforcing fibers, preferably short fibers, has proved to be advantageous. Such reinforcing fibers, for. Example of PBO, aramid, POD, etc. can be fire-retardant by themselves and thus ensure additional flame retardancy or fire protection.

The rubber mixture of the coating can according to the invention contain at least one flame retardant or be flame-retardant on its own.

If a flame retardant is used, it is preferably a halogen-free flame retardant or one which is a Has the lowest possible halogen content, so that in case of fire, the amount of toxic fumes remains low.

As a flame retardant all flame retardants known to those skilled in the art can be used.

Stannates such as zinc stannate or zinc hydroxystannate, hydroxides such as magnesium hydroxide or aluminum hydroxide, cyanurates such as melamine cyanurate, borates such as zinc borate, phosphorus-containing components such as resorcinol diphosphate or aromatic polyphosphates, nitrogen-containing components such as ammonium phosphate, intumescent mixtures, carbonates such as calcium carbonate or Magnesium carbonate, antimony trioxide, hollow microspheres, preferably in unexpanded form, or expandable graphite in question.

Intumescent mixtures expand to foams. They are used to protect combustible materials such as plastics or wood, but also steel, which loses its strength at elevated temperatures, against the effects of heat and fire.

Minerals with a flame retardant effect, such as, for example, sepiolite and / or hydrotalcite, can also be used as flame retardants.

The flame retardants can be used alone or in combination.

A further object is to provide a method for producing an article, in particular a metal-rubber element, which is characterized by an optimized fire protection behavior to meet the more stringent requirements, in particular those in EN-45545 described to fulfill. At the same time, the necessary physical properties of the article should remain at a comparable level and the complexity in the production process should not be appreciably increased.

• – Herstellen und Vulkanisieren des Artikels mit einem Grundkörper aus einem polymeren Werkstoff mit elastischen Eigenschaften und
• – Herstellen und Vulkanisieren des Überzugs, wobei der Überzug aus wenigstens einer Kautschukmischung gebildet wird und wobei die Kautschukmischung des Überzugs wenigstens ein Flammschutzmittel enthält oder von sich aus flammhemmend ist und
• – Zusammenfügen des vulkanisierten Artikels und des vulkanisierten Überzugs.

This object is achieved in that the method for producing the article, in particular the metal-rubber element, characterized by at least the following process steps:

• Producing and vulcanizing the article with a base made of a polymeric material having elastic properties and
• Preparing and vulcanising the coating, wherein the coating is formed from at least one rubber mixture and wherein the rubber mixture of the coating contains at least one flame retardant or is flame retardant by itself, and
• - Assembly of the vulcanized article and the vulcanized coating.

In this case, the article is preferably produced by means of injection molding (or injection molding, IM process) or transfer molding (TM) and Injection Transfer Molding (I-TM process) or compression molding (Compression Molding , CM method and Injection Transfer Molding, I-CM method).

The production of the coating is preferably carried out by means of transfer molding, but also the use of the injection molding is conceivable.

The assembly of the two separately manufactured components, i. the article and the coating is done by simply coating and optionally subsequently producing a compound as already described above.

The invention will now be explained by means of embodiments with reference to a schematic drawing.

1 shows a section through a metal-rubber element. The metal-rubber element has metal parts at different positions 3 on. The polymeric base body 1 with elastic properties is composed of a rubber compound. The rubber mixture of the main body 1 This is essentially responsible for the actual function of the metal-rubber element, while the rubber mixture of the coating 2 additionally contains a flame retardant and according to the present figure, the base body only partially covered.

LIST OF REFERENCE NUMBERS

1

Rubber mixture of the main body 1

2

Fire-retardant rubber compound of the coating 2

3

metalwork

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2014/019008 A1 [0006, 0006]
• WO 2016/045813 A1 [0007, 0009, 0022]

Cited non-patent literature

• EN45545 [0004]
• EN45545 [0008]
• EN45545 [0012]
• EN45545-2 [0012]
• EN45545-2: 2016 [0024]
• EN-45545 [0045]

Claims (6)

An article comprising a body made of a polymeric material having elastic properties, characterized in that the body has an article surface completely or partially provided with at least one coating, the coating being formed from at least one rubber compound and wherein the rubber mixture of the coating comprises at least one Contains flame retardant or is flame retardant by itself. Article according to claim 1, characterized in that it contains the rubber mixture of the main body as a rubber component NR and / or IR. An article according to claim 1 or 2, characterized in that the rubber mixture of the coating contains as the rubber component of EPDM and / or CSM and / or ACSM. Article according to one of claims 1 to 3, characterized in that the coating is additionally provided with a reflective and / or heat-insulating coating or with a flame-retardant flock. Article according to one of claims 1 to 3, characterized in that the article is a metal-rubber element.  Process for producing an article according to one of Claims 1 to 5, characterized by at least the following process steps: Producing and vulcanizing the article with a base made of a polymeric material having elastic properties and Preparing and vulcanising the coating, wherein the coating is formed from at least one rubber mixture and wherein the rubber mixture of the coating contains at least one flame retardant or is flame retardant by itself, and - Assembly of the vulcanized article and the vulcanized coating.

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