What is the composition and production of EPDM rubber

 

epdm rubber

What is the composition and production of EPDM rubber?

The use of ethylene propylene diene monomer (EPDM) rubber spans multiple industries and offers a host of applications from roofing membrane to door and gasket seals. Alanto offers a wide range of products made from EPDM rubber, in both open-cell and closed-cell form.

 

What is the composition of EPDM rubber?

EPDM is a copolymer of ethylene, propylene and a small amount of non-conjugated diene monomers (3% - 9%) which provide cross-linking sites for vulcanization (rubber hardening). EPDM rubber is an M-class synthetic rubber; the M classification comprising of elastomers with a saturated chain of the polymethylene type.

The ethylene content of EPDM rubber is around 45% - 75% - the higher the percentage, the more filler loading possibilities are presented. Dependent on the grade and formulation, EPDM rubber can withstand temperatures as low as -40℃ and as high as 100℃.

At Alanto, we offer both open-cell and closed-cell EPDM rubber sponge, each with their own benefits dependent upon their application. Both variants have excellent resistance to UV rays and do not degrade over time, rendering them an ideal option for outdoor applications.

Open-cell EPDM material allows for the ingress of air, dust, and moisture until it is compressed by 80% of its thickness - at which point it becomes closed-cell. This makes it ideal for applications that require the material to revert back to its original shape following compression. Open-cell foams are also processed and engineered to provide excellent sound-proofing as their composition allows for the efficient absorption of sound.

Closed-cell EPDM material does not allow air, dust, or moisture to permeate the material. This makes it ideal for applications that require a water-tight EPDM material, such as outdoor sealing and gasketing. Alanto offers a range of closed-cell EPDM sponges in the following densities:

Ref

Density (kg/m3)

DK1070

70-100

DK1075

75-105

DK2010

100-140

DK2015

125-165

AL43

270-330

 

The production of EPDM rubber

EPDM synthetic rubber was created in the mid-1960s, initially with the idea to replace the natural rubber used for products such as car and bicycle tyres. However, it was quickly realised that it was not suited to such applications, and other avenues were explored for this exceptional synthetic rubber. Due to its outstanding resistance to weather, ozone, and heat, applications in the automotive and construction industries were invested in and developed. Along with these industries, EPDM is now a key player in industries such as:

  • Body Armour & Personal Protection
  • Domestic Appliances
  • Engineering
  • Electrical & Lighting
  • Heating & Ventilation
  • Packaging & Logistics

 

What is the production process of EPDM rubber?

EPDM can be manufactured using one of three processes - slurry, solution, and gas-phase.

Slurry

Solution

Gas-phase

- The monomers and catalyst system are injected into a propylene filled reactor in this modification of bulk polymerization.

- Masses of polymer are formed that are not soluble in the propylene - reducing the need for solvents and solvent handling.

- Stable temperature control is facilitated by the low viscosity of the slurry.

- Polymerization of the ethylene, propylene and catalyst systems takes place in an excess of hydrocarbon solvent.

- Stabilizers and oils are added directly after polymerization (if required).

- Hot water, steam or mechanical devolatilization are used to flash the solvent and unreacted monomers, leaving only the EPDM compound.

- The remaining crumb-like polymer is then dried by either mechanical press, drying ovens, or dewatering in screens.

- The monomers, catalysts and nitrogen in gas form are fed in a reactor that consists of a vertical fluidized bed.

- Solid product is removed.

- Circulating gas is used to remove the intense heat of the reaction, which also fluidizes the polymer bed.

- Gas-phase does not involve the use of solvents, however, the process requires continuous injection of carbon black. This acts as a partitioning aid which prevents the polymer granules from sticking to each other and the reactor walls.

 

Alanto offers EPDM rubber solutions in the form of rubber tape, rubber coils, rubber sheets/rolls, and rubber gaskets, each tailored to suit your individual application. Contact us today to see how Alanto can find an EPDM solution for you.