Let's see what EPDM polymers are, those mixed with PP and what are the sources of their recycling.

In the world of polymers, rubber EPDM is defined, terpolymer, because it is obtained from the copolymerization of ethylene, propylene and a diene monomer.

In the analysis of EPDM components, the value of ethylene can be represented by a percentage ranging from 45 to 75 This percentage range affects the characteristics of the rubber mixture, in fact the higher the percentage of ethylene, the better the workability, loading and extrusion will be.

Regarding the peroxide-based vulcanization of EPDM rubber compounds, these are characterized by a higher cross-linking density than other similar polymers.

EPDM also lends itself very well to blends with polypropylene, as it has a stiffness and a high softening temperature, compatible with both polymers.

The technical characteristics of the blends between PP and EPDM depend on the degree of mixing of the components, in fact, with a percentage of PP around 90% the same technical characteristics of the original PP are obtained, but with a lower stiffness and softening temperature.

On the other hand, the blends that contain a percentage of PP around 40% will have the typical characteristics of a thermoplastic rubber. Furthermore, the choice of the type of polypropylene, whether homopolymer or copolymer, will change the final characteristics of the mixture.

What are the properties of EPDM?

EPDM products have good resistance to hot and cold water, heat resistance, ozone resistance, weather resistance and steam resistance .

On the other hand, they have low resistance to petrol, kerosene, aliphatic aromatic hydrocarbons, solvents and concentrated acids.

What are the uses?

The most common use of EPDM is certainly the automotive sector, where it is used for the following main products:

• door seals

• windows

• trunks

• windscreen

In the construction sector:

• roof membranes

• geomembrane for ponds

• mixed with polyurethanes they are used on floors, roofs, asphalt, brick and wood

• to create non-slip floors

• seals for fixtures

In the household appliances and systems sector:

• refrigerators

• radiators

• straps

• washing machines

• pipes

• electrical insulation

How to recycle EPDM

EPDM products can derive from the industrial sector, expressed in processing waste, or from the civil sector, as waste from differentiated collection.

In both cases, the objects to be recycled must be previously analyzed as they may contain materials other than EPDM alone.

For example, the recycling of car bumpers must be preceded by a process to remove any data or screws that could be contained in the product, or, in the post-consumer field, the bumpers could present harmful paints to the final quality of the raw material to be recycled.

Furthermore, often, in the automotive industry, EPDM components could have insulators attached such as, for example, the cross-linked polyethylene which worsens the quality of the waste to be processed.

Recycled EPDM is normally used in the form of ground material in various dimensional shapes, but also as a granule suitable for extruders or injection molding machines.

Automatic translation. We apologize for any inaccuracies. Original article in Italian.