Elastomers EDPM, NBR, FPM: the raw materials of the BUCCHI seals

Elastomers EDPM, NBR, FPM: the raw materials of the BUCCHI seals

The choice of materials for seals is essential, above all in the case of products and fittings for specific applications and sectors.
A suitable raw material is in fact an indispensable feature to ensure the quality, longevity and performance of the product. For this reason, the choice of BUCCHI S.r.l. to produce and use elastomer seals allows to create high-level products with extraordinary performance.

In general, the main characteristics of elastomer seals concern:

• the ability to adapt to dynamic movements, or to undergo significant elastic deformations, without changing the original shape of the gaskets
• resistance to low temperatures
• resistance to extreme thermal conditions

Let’s see in detail, together with Dr. Anna Valentini, Head of Laboratory and Quality Control of BUCCHI Srl, the rubber raw materials used in the company.

NBR
This elastomer is a copolymer of butadiene and acrylonitrile and is used for most seal applications for conventional fluids.
NBR elastomers offer good properties of compression, tear and abrasion resistance; good flexibility and high breaking load (up to 210kg cm²).
The operating temperature varies from -30 ° to + 100 ° C, and for a short time up to 120 ° C.
NBR seals are impermeable to gases and present an excellent chemical resistance in the presence of town gas, butane, propane, fatty acids, water and detergents.

EPDM
It is an ethylene and propylene-based rubber plus a third monomer (diene). For its chemical structure it is particularly resistant to fluids such as water and vapour. The gaskets in E.P.D.M. they have a high resistance to permanent deformation and a good breaking load (up to 180 kg cm2), with an operating temperature from -45 ° to + 130 ° C, up to peaks of + 150 ° C.
The EPDM compound offers a versatile solution and resists the corrosive action of chemical agents, oxidation, the ozone, heat, heat ageing; its resistance to high concentration acids is also good.
However, it must be emphasized that this material is not compatible in applications with gasoline, lubricating oils, aromatic solvents and hydrocarbons.

FPM
This fluorinated elastomer possesses an exceptional resistance to heat and to atmospheric and chemical agents. It has a low permanent deformation and a breaking load of over 140 kg cm2.
The operating temperature varies from -30 ° to + 200 ° C, up to peaks of + 280 ° C.
Fluorinated elastomers have an excellent chemical resistance in the presence of lubricating oils, aliphatic and aromatic hydrocarbons, petrol, hydraulic liquids not readily flammable, caustic soda, formaldehyde, chloroform, acids and numerous other chemical products. Their resistance to oxidation, ozone, atmospheric agents and ageing in sunlight is outstanding.
The FPM compound is not recommended in contact with low molecular weight esters, ethers, ketones, and amines.