Balancing conductivity and processability in conductive foams applications
Conductive polyolefin foams need to combine reliable electrical conductivity with good mechanical performance and stable processing. Achieving that balance can be challenging and places particular demands on both formulation and process conditions.
Why conductive foams are challenging to produce
Electrical conductivity in many polyolefin foams is achieved by adding conductive carbon black, which forms a conductive network throughout the polymer.
During foaming, this network is stretched as the material expands and millions of small cells are formed. At the same time, carbon black reduces the melt strength of the polymer.
If the formulation and processing conditions are not optimally balanced, manufacturers may experience:
- unstable or irregular cell structures
- reduced melt strength
- variation in electrical conductivity
- cell collapse
- a narrow processing window
In chemically crosslinked foam production, crosslinking can help increase melt strength, support a more stable foam structure and more consistent electrical performance.
The formulation needs to match the production process
There is no single formulation that works for every conductive foam process. Polymer type, blowing agents, peroxide systems, antioxidants and production technology all influence the final result. This means the conductive concentrate must be selected and adjusted to the specific application and process.
Our partner Premix develops PRE-ELEC® conductive concentrate solutions for several polyolefin foam technologies, including:
XLPE foams
For chemically crosslinked block foam and continuous sheet extrusion.
EVA foams
For applications including batch-produced block foam.
PP and PE bead foams
For bead foam processes followed by steam chest moulding, where customised conductive grades are often required.
Material and process development go together
Choosing the conductive material is only one part of the solution.
Processing conditions have a direct influence on foam structure and electrical performance.
For manufacturers developing a new conductive foam, or improving an existing process, this makes application testing and formulation work particularly important.
Alsiano works with Premix to give Nordic plastics producers access to specialised conductive compounds and concentrates together with technical application knowledge.
Working with conductive polyolefin foams?
Contact us to discuss your polymer, production process and required electrical performance.
