• Wrong grade selection

• Bad dispersion

• Choose black that meets XC type black standard

• Optimize dispersion to get excellent smoothness

• Low conductive black loading

• Poor dispersion

• Wrong grade selection or does not meet the XC black standard

• Increase loading of conductive black

• Select XC black designed for the specific cable segment, i.e. for bonded shield or strippable shield.

Excessive break down of the carbon black structure by:

• Excessive shear
• Excessive compounding time

Undispersed conductive black:

• Inconsistent pellet quality due to pellet degradation during transport
• By insufficient shear during compounding
• Wrong grade selection

• Optimize compounding conditions by reducing shear, i.e. by increasing temperature, decreasing shear.
• Check conductive black quality during transport. Optimize conveying parameters.
• Increase conductive black loading to increase viscosity.
• Increase shear or length of mixing cycle
• Check resin quality (viscosity).
• Select XC type blacks specified for the specific cable segments.

• Too low carbon black loading (to attain optimal viscosity for optimal dispersion)
• Wrong grade selection

• Adjust conductive black loading to attain the optimal viscosity for dispersion.
• Select conductive black with better surface smoothness performance. XC type black have inherent superior dispersability.

• Undispersed conductive black:
• Inconsistent pellet quality due to excessive degradation in conveying system
• By insufficient shear during compounding
• Poor homogeneity:
  • By insufficient distributive mixing)
  • Polymer gels (degradation problems)
  • Oxidized particles

• Check conductive black pellet quality during transport. Optimization of the conveying parameters.
• Adjust conductive carbon black loading f to achieve desired viscosity to attain optimal shear.
• Increase shear or length of mixing cycle
• Check resin quality (viscosity).
• Optimize extrusion conditions, e.g. increase back pressure by using finer screen packs, reduce temperature.
• Use thermally stabilized raw materials
• Ensure machine is clean
• Use anti-oxidants during shut-down period

• Excessive of moisture in raw materials
• Die design and geometry
• Process conditions
• Melt rheology
• Compatibility between raw materials
• Presence of low molecular weight species
• Thermal stability of raw materials

• Dry raw materials, store in dry conditions
• Reduce extrusion temperature
• Use highly compatible and thermally stable polymers and additives
• Use processing aids, such as fluoropolymers