One of challenges of making high concentration carbon black masterbatch is how to feed such fine and light weight powder into twin screw extruder. Not carbon black alone, all fine and fluffy filler alike has the same feeding and distribution issues, such as graphite, super fine talc and CaCO3.
There are some traditional ways including batch kneader or high speed mixer with crusher. Either way has to be processed in two steps which involve more procedures and labor work. Our innovative one-step method eliminated pre-treatment process; yet keep good distribution of high concentration of carbon black.
The new facility was named CKC (Continuous Kneader Compounding) which is a kind of tandem extrusion system comprised of one continuous kneader plus one twin screw extruder. The diameter of continuous kneader is much greater than twin screw extruder, so it features good intake capability. The special designed kneading elements can cram and distribute carbon black into polymer resin before entering into twin screw extruder for further dispersion mixing.
What is more important is that the CKC system can work with loss-in-weight dosing system which makes the feeding process fully automatic instead of traditional way which has to weigh each ingredient in batches and premix it. The Continuous Kneader is dedicated to conveying, plasticizing and distributing, so that the twin screw extruder can work on dispersing filler more dedicated.
This new CKC (Continuous Kneader Compounding) can apply for HFFR (Halogen Free Fire Retardant) cable material with high percentage of filler. PP/PE compounding plus more than 80% super fine CaCO3 (>3000 mesh) or talc (>3000 mesh). PP/PE masterbatch plus more than 40% of carbon black or graphite filler. We have applied this system to make graphite and carbon black masterbatch for EPS beads production and XPS production.
With this new CKC system, the productivity can be increased by 50%, even 100% when the fine filler concentration is high.