Granic® is a granulated calcium carbonate that can be used easily in the thermoplastic processing industry.

Granic® can be added to almost all polyolefins improving some of the polymer properties and offering economic advantages. The special form and composition of Granic® means that it can be handled easily without pre-drying. It is also easy to disperse in most industrial processes.


Economic Advantages for the Processor

The most interesting economic advantage to be gained by the addition of calcium carbonate to polyolefins results from the improved thermal conductivity. The higher the thermal conductivity, the less time is required to heat up or cool down the plastic mixture. The thermal conductivity increases in a linear fashion with the calcium carbonate content.

Process speeds can be increased depending on the calcium carbonate content and the wall thickness of the plastic articles. For example, the injection moulding cycle time can be shortened and the output of an extruder increased.

A further important aspect is that the flexural modulus is increased by the use of Granic®. This makes it possible to reduce the wall thickness of various components resulting in significant raw material cost savings.


Granic® Loadings

For the different uses, the following loadings are recommended:

  • Woven tapes / raffia / woven-non-woven
      multifilament 1-15%.

  • Carrier bags/heavy duty sacks 5-35%.

  • Agriculture film (mulch and silage)
      15-40%.

  • Shrink film 2-4%.
  • Technical film (building and furniture)
      5-35%.
  • Thermo-forming sheeting 20-50%.
  • Injection moulding 20-50%.
  • Pipes/profiles/sheets 7-50%.
  • Containers (blow moulded) 7-30%.
  • Rotomoulding 10-40%.


Selected Properties

In general, the flexural modulus, distortion temperature under load and the density increase whilst other properties such as the toughness or elongation at break are only marginally influenced.


Shrinkage

The nodular shape of the calcium carbonate particles together with their low aspect ratio of about 1, mean that the particles do not orientate themselves when Granic® is used.

The result is that the shrinkage in the machine and transverse directions are not influenced by the shape of the mineral particles. Instead, their presence helps to reduce the polymer orientation. In practice it results in finished articles largely free of residual stress.

Advantages by use of Granic® in Polyolefins

  • Modification of polyolefins without
      additional costs.

  • Improved thermal conductivity of
      the polymer.

  • Increase in stiffness.

  • Improved dimensional stability.
  • Higher distortion temperature under load.
  • Increased puncture-resistance of film
      (dart test).
  • Anti-blocking.
  • Easier further processing such as heat
      sealing, printing, punching, etc.