5A kneading blocks are used in many of the high-performance twin screw extruders of the ZSK series from Coperion.
The 5A kneading blocks protected by EP patent number 1 508 424 B2 have been proven to prevent the torsional vibration occurring in high performance extruders. These extruders are often stimulated in the resonance frequency, that may lead to cracked shafts or coupling malfunctions. To counter these effects, Coperion developed kneading blocks that can help to reduce the stimulating forces. Coperion owns said patent for the 5A kneading blocks and in April 2016, the company was able to successfully defend it. Since registering the patent in 2003, Coperion has primarily used the 5A kneading blocks for large-scale machines to avoid possible damage.
Coperion also holds patents for the 5A kneading blocks in China, Japan, India and Taiwan.