There are two main methods that are used to colour plastic products and packaging; raw pigments and masterbatch. Deciding which one is right for your products can prove to be a bit of a challenge, so we have provided the benefits and drawbacks of each method.
Masterbatch can typically be viewed as more advanced by some manufacturers, but it is important to understand how each process works so you can decide which is best for you.
Raw pigments are mixed with plastic pellets in a hopper. This process uses a ratio of 2% pigment in terms of volume. Sometimes, the pellets need to be dried out before adding the powder. Then, the dry pigment sticks to the plastic pellets, enabling it to reach the colour.
This method is best used in more specific circumstances. For instance, if there is a small amount of custom colour. Pigments are also seen as more cost-effective and come in a range of colours. They are also easy to mix, making the process faster and straightforward.
Since powders can get quite messy, there is a risk the raw pigments will become airborne during the colouring process and, as a result, they could contaminate nearby manufacturing lines. Additionally, the fact they are powders means they can, at times, be harder to store.
This process involves mixing concentrated pigments together under heat, followed by placing these into a binder, to create granules that will make your end-product. Since they are in a pellet form, some manufacturers can view them as easier to store than powders.
Abbey Masterbatch has listed the advantages on their blog. These include the fact that it’s in pellet forms, which, reportedly, makes the manufacturing process easier. With masterbatches, the colouring will also stay consistent throughout, avoiding patchiness and, additionally, the opacity of the product can be changed with ease.
The main disadvantage of masterbatch is the potential insufficient dispersion of the pattern of colouring due to the fact they are pre-mixed. Another drawback associated with this form of colouring is the increased risk of the colourant clumping up during the colouring process.
Therefore, both have their pros and cons, so reading through these might be able to help you decide which is the best method to use to add colour to your products and packaging.