Supply Chains for Compounds

Processors may also perform compounding themselves, to customise materials for their own specific requirements. This may 

Masterbatches are concentrated mixtures of colours and/or additives incorporated into suitable carrier materials. This enables easy incorporation of the selected masterbatch formulation into the production process. Often, masterbatches are used to improve the downtime when changing colour and materials, which improves production efficiency. It is more expensive to buy a masterbatch than an additive. However, the advantages, especially in cases where nmnerous colour changes are required, can quickly repay the cost. For example, carbon black pigment is very fine and incredibly difficult to remove from feed hoppers and mixers (and the production workers ), whereas a black masterbatch containing perhaps 20% black pigment in a carrier material such as low-density polyethylene (LDPE) can be added to the mixture at 1-5%, leaving the hoppers and mixers easy to clean, ready for the next blend. 

Whether an additive is used in concentrated masterbatch form or in its standard form will vary depending on the requirements of particular producers. Masterbatches are routinely used for blow moulding and film blowing in commodity plastics such as polypropylene (PP), LDPE and high-density polyethylene (HOPE). 

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