Unmistakably the best

Sponge rubber

Our sponge rubber mouldings and profiles are suitable for a multitude of applications throughout industry. The softness, elasticity, surface finish, shape and durability of sponge rubber can be varied to match the requirements of virtually any application. Precision seals, soundproofing panels, flexible supports... the possibilities are endless.

Take a look at our sponge rubber products and you will be amazed how versatile this material is. Our products are reliable and durable, too. Sponge rubber from KÖPP – Unmistakably the best!

Areas of application

Sponge rubber
Sponge rubber

What is sponge rubber?

Sponge rubber differs from cellular rubber in that it is has a mixed open and closed cell structure. This rubber material has a high compression elasticity and good resilience.

It is available as natural or synthetic rubber in forms such as chloroprene, EPDM, silicone, Buna or fluorine rubber.

The raw materials used bond particularly well with the special material structure of sponge rubber. At first glance, sponge rubber appears to have the same appearance as cellular rubber. Closer inspection will reveal the difference. Inside, sponge rubber has a mixed open and closed cell structure.

You can download our data sheets on sponge rubber at our Service Centre.

Technical data

It differs from cellular rubber also in that it requires the addition of an outer skin if it is to be used for sealing applications. KÖPP sponge rubber profiles and round cords have a high compression elasticity combined with particularly good resilience.

Under light pressure the profile flexes out to the surrounding surfaces making a perfect seal. The softness of sponge rubber is varied by using special mixes and by varying its volume by weight, i.e. its density. There are two methods for manufacturing sponge rubber profiles: Moulded sponge rubber and extruded sponge rubber profiles.

  • Outstanding sealing properties (with skin)
  • High compressibility
  • Good insulation properties
  • Flexible processing options
  • Very high abrasion resistance due to closed outer skin
  • Mixture with high resistance to temperature  and ageing (EPDM)
  • Mixture with high flame resistance and oil resistance (CR/NBR)
Manufacturer, processor, dealer



NR – Natural rubber

High elasticity, good stability under cold conditions.

CR – Chloroprene rubber

High flame retardance, good ozone, weather, chemical and ageing resistance

SBR – styrene butadiene rubber

Good mechanical properties, good heat resistance and ageing stability

NBR – Acrylonitrile butadiene rubber

Good resistance to petrol, mineral oils and greases.

EPDM – Ethylene propylene diene monomer

High ageing stability, high resistance to ozone, good resistance to heat and chemicals.

HNBR – Hydrogenated nitrile butadiene rubber

Outstanding resistance to acid, ageing and ozone.

VMQ – Silicone rubber

For high-temperature applications and damp heat, high resistance to fuels, oils and grease.

FPM – fluorocarbon rubber

Very high heat and chemical resistance, high flame retardance, weather and ageing resistance.

Sliding bearings


Round cord, square and moulded sponge rubber profiles are vulcanised in heated metal moulds. During the vulcanising process, chemical cross-linking takes place and it is this feature which gives sponge rubber is rubbery elastic characteristics. Adding foaming agents creates the cell structure and the final shape of foam rubber. The final shape depends of course on the production mould.

Extruded profiles, on the other hand are not shaped in a closed mould. They are formed by extrusion, that is by forcing a special rubber mixture through a nozzle or die which has the final shape of the finished profile. Vulcanising takes place outside the die at room temperature.

KÖPP sponge rubber profiles are available in standard lengths as semi-finished products or as ready made parts custom-made to your shape and version requirements.

Bonding, cut-outs or punched parts

Sponge rubber round cord, square profile and moulded profile are available in self-adhesive versions ideal for making a clean, durable seal around circular and square openings. This is a tried-and-tested, cost-effective solution for sealing large openings in containers, tanks and casings.

To make fitting easier, we supply versions which are self-adhesive on one side or both sides.

Sponge rubber sheets are ideal for custom cut-outs or punched items.

You can find our sponge rubber profile overviews at our Service Centre.

Moulded parts 
Moulded parts
Sealing rings 
Sealing rings
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