This is a synthetic, vulcanized rubber that is made by kneading together several materials. This includes an organic agent and a crosslinking agent. An additive, often times sulfur, is usually added to make it more durable.

There are many characteristics to the rubber sponge that allow for several variations. You can choose between different foam structures, expansion ratios and hardness. The chemical properites can also be chosen, such as whether it is fire resistant(CR) or chemical resistant(EPDM). EPDM even has resistance to some acids and alkalis.


Closed Cell

  • C-4305
  • CR-250NN


Semi-closed Cell


Main Applications

Cushioning material, sealing, packaging materials, window frame rubber, rugs,
packing car parts, OA equipment, construction equipment, medical equipment,
sports O-rings, seals, and gaskets.


NR – Natural Rubber

NR, an abbreviation for Natural Rubber, comes from the sap(latex) of a rubber tree. This tree is mainly grown in Southeast Asia.
Since it is essentially raw latex, it allows for the manufacturing of gloves, adhesive, and foam rubber.
It provides workability, elasticity, abrasion resistance, and cold resistance among other things.
However, it is lacking in heat resistance, oil resistance, weather resistance, and ozone resistance. It is also relatively inexpensive and is commonly used
in industrial products and large tires. Essentially, it works well with anything that requires abrasion resistant, vibration resistant, high strength rubber.

CR – Chloroprene Rubber

CR is an abbreviation for chloroprene rubber. It is flame retardant and has excellent chemical and weather resistance.
Due to its large range of properties, it is the most widely used rubber in industry.
Our CR rubber products are high on the UL safety scale (flame resistance rating)
while having low sulfur content and conductivity.

EPDM – Ethylene-Propylene-Diene Monomer(M-class)

EPDM is an abbreivation for Ethylene-Propylene-Diene-Monomer. It is sometimes referred to as EP or EPM.
It has excellent weather resistance, ozone resistance, chemical resistance, and heat resistance.
It also has good electrical insulating properties. It is typically used outdoors, in general industrial rubber products, and for electrical insulation.
It also has low sulfur content and low conductivity.

NBR – Nitril-Butadiene Rubber

NBR is an abbreviation for Nitirl-Butadiene Rubber.
It has a very high oil resistance.
However, it has poor resilience and bad ozone resistance.
Often used in industrial rubber products, it is common to see it used in mechanical parts in factories that deal with oil.

Si – Silicone Rubber

Si is an abbreviation for silicon rubber. It may also be referred to as SR, VMQ, or Q.
It has excellent heat resistance, cold resistance, and ozone resistance.
It is weak in strength. In particular, di-methyl silicone rubber has weak resistance to steam.
Methyl-vinyl silicone rubber on the other hand, is resistant to high pressure steam and is widely used in heat resistant rubber products.
This type of rubber is used in high temperature environments, often times the food industry. An appropriate temperature range is from -60 C-200 C. This ensures that everything is up to Food Sanitation Law.

For all your rubber, urethane, and polyolefin needs, please leave it up to Chiyoda Rubber.


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