WO2018046150A1

WO2018046150A1 - Article, in particular a metal-rubber element for rail vehicles

Info

Publication number: WO2018046150A1
Application number: PCT/EP2017/064240
Authority: WO
Inventors: Christoph Zander; Hans-Harald Kielbasiewicz; Mark LINDENBERG; Thorsten Leethaus
Original assignee: Contitech Luftfedersysteme Gmbh
Priority date: 2016-09-12
Filing date: 2017-06-12
Publication date: 2018-03-15
Also published as: DE102016217333A1

Abstract

The invention relates to an article comprising a main body of a polymer material with elastic properties, in particular a metal-rubber element for rail vehicles. To improve the fire-retarding properties, the article, in particular the metal-rubber element, has a main body of a polymeric material with elastic properties, wherein the main body has an article surface that is completely or partially provided with at least one coating, wherein the coating is formed by at least one rubber compound and wherein the rubber compound of the coating contains at least one flame retardant or is inherently flame-retarding.

Description

ContiTech Luftfedersysteme GmbH

description

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

The invention relates to an article having a base body of a polymeric

Material with elastic properties, in particular a metal-rubber element for S rail vehicles.

Rail vehicles have metal-rubber elements in various designs as suspension systems that are essential for the comfort and safety of

Rail vehicles contribute. These suspension systems have not only suspension, but also leadership and damping tasks. You will find u.a im

Primary spring area between wheelsets and bogies and take over there

mainly the wheelset. In the secondary spring range between bogie and car body, the metal-rubber elements serve as elastic storage of

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, for example, of motor vehicles or rail vehicles and / or serve vibration damping, are under

Use of elastomeric mixtures, also referred to as rubber compounds produced. These elastomeric blends commonly used for the basic properties of such articles are well known. Article with

outstanding elastic properties, such as metal-rubber elements or vibration dampers, preferably contain vulcanized rubber mixtures which are predominantly based on natural rubber (NR) and / or polyisoprene rubber (IR). However, articles with these elastomeric blends show significant disadvantages in the art Fire behavior. In case of fire, dense flue gases are produced. At the

Combustion process of said elastomeric mixtures, which are based predominantly on NR and / or IR, the heat release rate is particularly high.

Due to the increased requirements in recent years regarding the

Fire protection, which is particularly evident in the stricter fire protection standard EN45545, results in an increased demand for fire protection-optimized polymer articles. These fire protection requirements, the elastomeric mixtures, which are mainly based on NR and / or IR, mainly 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, this leads

Measure in the affected articles usually to the fact that the physical properties, especially the suspension, setting or vibration characteristics worsen significantly.

In WO 2014/019008 AI is proposed to solve this problem, a

exclusively sulfur-crosslinked additional outer layer comprising a vinyl acetate-containing thermoplastic polymer, a double bond-containing, unsaturated elastomer and at least one flame retardant to use. 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, if necessary, a vulcanization process must therefore 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. Especially on

Polymer blends based predominantly on NR and / or IR show significant reversion processes on overvulcanization.

From WO 2016/045813 AI is known in particular for air springs to overcome these disadvantages by a coating of a textile or a shrink film. It was However, found that such a textile coating or the coating of a shrink film leads to a significant overhead in production, since these additional materials not only purchased or possibly even costly self-made, but must also be stored and processed. The textile

Coating usually has to be adhesively bonded to the base 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 behavior to the more stringent requirements, in particular those in EN45545

described to fulfill. At the same time, the necessary physical

Properties of the article remain at a comparable level and the

Complexity in the manufacturing process can not be significantly increased.

The present invention is also intended to simplify the production scale

Alternative, in particular for metal-rubber elements, to provide the solution described in WO 2016 / 045813A1.

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 at least one

Contains 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 thermal radiation, so that the combination of coating and base body meets the requirements of EN45545, in particular the requirements of EN45545-2. The coating consists of at least one rubber mixture, the at least one Contains flame retardant or from a rubber mixture, which is fire-retardant by itself, ie due to a suitable choice for the individual

Mixture ingredients does not require any additional flame retardants 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 form-fitting

Connection between the coating and the body, so that no additional fasteners are required. No tools are needed for this type of connection. In particular, for high-speed applications but it is also a screw connection 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

2016/045813 AI 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 on the entire

Articles extend so that the body is completely covered by the coating or the coating is only on certain exposed areas of the metal-rubber element, which are particularly at risk of fire.

According to §4.3.4 of EN45545-2: 2016 it is possible that small, unprotected areas up to 0.2m ² are permissible 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 of a rubber mixture, which is preferred

is thermoplastic, containing at least one rubber component and other Mischingingredienzien. As rubber components may be mentioned in particular:

Ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM),

Nitrile rubber (NBR), (partially) hydrogenated nitrile rubber (HNBR), fluoro rubber (FKM), chloroprene rubber (CR), natural rubber (NR), deproteinized natural rubber (DPNR), epoxidized natural rubber (ENR), styrene-butadiene rubber (SBR), isoprene rubber (IR), butyl rubber (HR), bromobutyl rubber (BIIR), chlorobutyl rubber (CUR), 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 aforementioned 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 NR and / or IR as

Rubber component used for a metal-rubber element.

The usual compounding ingredients include at least one crosslinker or crosslinker system (crosslinker and accelerator). additional

Mixture ingredients are usually still 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, the general state of the

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 (HR), Bromobutyl Rubber (BIIR), Chlorobutyl Rubber ( CUR), 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 aforementioned types of rubber, for example, a (A) CSM / NR blend, (A) CSM / CR blend, CR / NR blend, NR / IR blend, NR / BR - Cuttings 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 shows a favorable one

Processing behavior, is inexpensive and stable against many polar

Solvents.

Mixture ingredients are usually still a filler and / or a

Processing aids and / or a plasticizer and / or an aging inhibitor and optionally further 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 at least one

Contain flame retardants or be flame retardant by itself.

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

Resorcinoldiphosphat or aromatic polyphosphates, nitrogen-containing components such as ammonium phosphate, Intumeszenzgemische, 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 burn flammable

Materials such as plastics or wood, but also steel, which at elevated temperature its

Loss of strength, to protect against the action of heat and fire.

Also minerals with flame retardant effect, such as sepiolite and / or

Hydrotalcite, can be used as a flame retardant.

The flame retardants can be used alone or in combination.

Another object is to provide a method for producing an article, in particular a metal-rubber element, which is characterized by an optimized

Fire safety performance in order to meet the more stringent requirements, in particular those described in EN-45545. At the same time, the necessary

physical properties of the article remain at a comparable level and the complexity in the manufacturing process is not significantly increased.

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:

Manufacture and vulcanize the article with a base of one

polymeric material with 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 on its own

is flame-retardant and

- Assembly of the vulcanized article and the vulcanized coating.

The article is preferably produced by injection molding (IM) or transfer molding (TM) or Injection Transfer Molding (I-TM) or

Compression Molding (CM) and Injection Transfer Molding (I-CM).

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. of the article and the coating is done by simply coating and optionally subsequent

Producing a connection as already described above.

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

Fig. 1 shows a section through a metal-rubber element. The metal-rubber element has metal parts 3 at different positions. The polymeric base body 1 with elastic properties is constructed from a rubber mixture. The

Rubber mixture of the base body 1 is 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, only partially covers the base body. LIST OF REFERENCE NUMBERS

(Part of the description)

1 rubber mixture of the main body 1

2 Fire-protected rubber mixture of the coating 2

3 metal parts

Claims

claims

1. article having a base body made of a polymeric material having elastic properties, characterized in that the base body a

Having article surface which is wholly 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 on its own

flame retardant.

2. Article according to claim 1, characterized in that the

Rubber mixture of the main body contains as a rubber component NR and / or IR.

3. Article according to claim 1 or 2, characterized in that the

Rubber mixture of the coating as a rubber component EPDM and / or CSM and / or ACSM contains.

4. 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.

5. Article according to one of claims 1 to 3, characterized in that the

Article is a metal-rubber element.

6. A method for producing an article according to any one of claims 1 to 5

characterized by at least the following method steps:

Manufacture and vulcanize the article with a base of one

polymeric material with 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.