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Colours and Additives for Injection Moulding

One of many injection moulding advantages is that plastics can be coloured making your part more customisable to your requirements. Whether for cosmetic or functional purposes, it is possible to match any colour to achieve the desired results. There are a variety of possibilities when it comes to colouring the injection moulding material depending on the stage that the colour is added.




Compounding provides the greatest level of consistency for a chosen colour. To maintain the purity of the injection moulding material and maximise the performance of structural parts, the pigments are polymerised with the base polymer. As a result, pellets arrived colours, requiring no premixing and measuring of material.




Masterbatches are most commonly produced as concentrated pigments held in a solid carrier resin and cut into granules, but liquid masterbatches are also available. The granules containing the pigment melt and mix with the plastic as it moves through the barrel of the injection moulding machine before the cavity is filled. Colours can be chosen from a range, or a specific match selection. Unlike compounding, colour is measured out by the plastic injection moulding processor, requiring the weighing and mixing of masterbatch and base polymer at a specific ratio to control the final colour.




Compounding is where the base material is specifically coloured in a controlled process prior to moulding, whereas the masterbatch is concentrated coloured pellets or liquid that are mixed with the base material as it melts during the injection moulding process.  Both methods can achieve great results, but designers should take into consideration that the same colour may appear very different depending on the surface finish and wall thickness of the part.


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CJ Tool & Mouldings offer a full range of plastic injection moulding services, with a customer centred and personal approach. We pride ourselves on delivering quality products to meet customer needs, with a strong focus on quality service and value. CJ Tool & Mouldings are a dynamic and growing business through people product partnership. 

Added: 14 Oct 2019 14:50

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