Kumho NBR MB is a Carbon Nano Tube master-batch based on acrylonitrile-butadiene rubber (NBR)
that contains MWCNT at a concentration of 16.7% by weight (20 phr). The acrylonitrile
contents in NBR is 34%. Higher concentration of CNT (over 20wt%) is available.
GRANOC high thermal conductive products can fulfill growing needs of thermal management in electric cooling, for satellite and other applications.
The heat conductivity is up to 900 W/mK.
Yarns, fabrics and chopped fibers are available.
Krefine special carbon for permanent dissipative properties
Krefine enables you to produce compounds with defined electrical conductivity in the range of 10E5 to 10E11 Ohm. The accuracy is +/-1 decade and improves the production yield dramatically in a wide production parameter window.
Comaprison to carbon black:
Carbon black is produced out of petroleum. It has a large surface-area to volume – ratio and with a particle size of 10 to 300 nm this leads to agglomeration up to 100µm in diameter. The dispersion in polymers is not easy, so the electric conductivity varies a lot in the compound and the final plastic parts.
If you want to produce a conductive material with a surface resistance of i.e. 10³ Ohm, you put just as much of CB in the compound as you like.
But if the demand of your customer is a dissipative technical part which does not block the electricity nor let it through instantly with a spark- then you have to adjust the recipe very carefully and still might have a high scrap percentage. And this is not only the compound material you have to consider but also the machine time, energy, personal costs and most likely quality checks for every single item coming out of the machine.
Krefine material: With Krefine this huge amount of waste is reduced not only in the technical parts but also in the resin production as well.
Krefine is made of pitch and has a particle size of 22µm, which is very large compared to carbon black. The dispersion in the polymer matrix is much more even and therefor the variance in conductivity very narrow.
In the chart a graph shows the surface resistance of plastic compounds with different amounts of carbon fiber plus different amounts of Krefine. Naturally without the fillers, the polymer acts insulative, means, no electron will pass. With carbon fiber in it (or carbon black), the resistance soon will be gone and the material lets every electron through. The step between isolative and conductive is very small, which is why the machine adjustments are so difficult.
Krefine added to the compound forms small “bridges” between the longish carbon fibers. The electric charge “jumps” from them to the round Krefine particles and to the next fiber. This process takes some time (O ˜ cm/s) and the more time the more “insulation”.
The amount of Krefine adjusts the time / level of “dissipation”, the amount of carbon fiber is depending on the other components and the final application. Higher content of Krefine can stabilize surface resistance level. Adjusting the desired value is done by changing the carbon fiber content.
Krefine helps creating a broad production window for electric dissipative material and reduces the waste dramatically to considerably below 10%.