COMPOUNDS | ELECTRICALLY CONDUCTIVE
Right: Colloids has been optimising
performance of its E-Tec range of electrically conductive products
performance for film, sheet and profile extrusion, injection moulding, vacuum forming and closed cell foams. The programme was initiated to establish where and how improvements could be made to all aspects of the product develop- ment cycle. The aim was to improve
performance in terms not only of electrical conductivity, but also customer product manufacture and functionality, mechanical property retention, and economics. The additive system used in the E-Tec range is mainly carbon based; selection determined by the level of permanent electrical conductivity required, base polymer and end application. Each product in the E-Tec range has been targeted at particular polymer conversion processes and market applica- tion areas.
New additions to the range include bespoke electrically conductive polymer specific concen- trates formulated to individual customer’s require- ment as well as synthetic and graphite-based, graphene conductive compounds. Formulations were developed based on the need
Below: Grafe’s conductive range includes antistatic masterbatches to prevent dust build-up
to ensure easy manufacturing, including good dispersion of the conductive additive. Emphasis was not only placed on the selection of a conductive additive with the correct functionality on the particle surface, but also on the additives required to assist dispersion, as well as stabilise the compound. Developing and retaining the mechanical character- istics of the base polymer, with the possibility of rheology modification, was also considered. “The compounding phase is critical to the success
of the electrically conductive compound,” says Shazia Akhtar, Senior Analytical Chemist at Colloids. “During the development process, the choice of
main compounding method, control of shear development by adjusting mixing screw geom- etries and feed characteristics, along with other processing factors such as residence time, were established for each individual formula.” Akhtar says
formulation and compounding technol-
ogy are critically important.
“Conductive additives need to be dispersed to an optimum level to reach the percolation threshold at the lowest concentration for a given electrical conductivity requirement. The lower the concentration of conductive additive, the less of a detrimental impact it will have on the mechanical characteristics of the final product. The dispersion characteristics must be carefully monitored to ensure that the conductive network is not destroyed by excessive mixing.” Specialty compounder Witcom claims one of
the broadest range of carbon powder-modified conductive compounds, based on polymers ranging from polyolefins to high temperature plastics. Recent additions include PES and PBT. Christine Van Bellingen, Business Development Manager Conductive Materials says: “The key breakthrough here was to come up with formula- tions that have sufficient impact strength.” Van Bellingen sees considerable opportunity in
the growth of radar-based autonomous driving technologies in the automotive sector, such as adaptive cruise control and collision detection. She says Witcom, part of the Wittenburg Group, has been at the forefront of radar-absorbing materials for more than 10 years. New developments at the company include materials that offer thermal conductivity as well as radar absorption, and materials that offer absorption over a wider frequency range.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.ocsial.com �
www.lehvoss.de �
www.avanzarematerials.com �
www.nanocyl.com �
www.cabotcorp.com �
www.carbonx.nl �
https://en.procotex.com/ �
www.arkema.com �
www.basf.com �
www.grafe.com �
www.colloids.com �
www.wittenburggroup.com (Witcom)
50 COMPOUNDING WORLD | February 2020
www.compoundingworld.com
IMAGE: GRAFE
IMAGE: COLLOIDS
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