One of the most significant characteristics of PVC is that it can be coloured with pigments or with masterbatch, thanks to the intrinsic versatility of this polymer, which is normally used in powder form, and therefore allows the use of pigments without any decanting issues during production.
However, Delta Tecnic, a company specializing in the production of masterbatch for the PVC industry, highlights the advantages of masterbatch and recommends its use over pigments to obtain optimal results in both products and production.
Pigment concentrate encapsulated in the plastic matrix
Masterbatch is a pigment concentrate encapsulated in the plastic matrix that offers excellent dispersion. Thanks to this encapsulation, masterbatch is a product that does not transfer colour by contact but only during passage through the extruder. Therefore, its use significantly reduces the need to clean the facilities, which in turn decreases production time and improves efficiency.
Pigments, on the other hand, transfer colour through simple contact and since they must pass through a mixing process prior to extrusion, this means the elements used to mix and transport the material to the extruder require cleaning. Replacing pigments with masterbatch can achieve an 80% reduction in clean-up time, leading to an improvement in productivity, since the time needed to change from one colour to the next is reduced.
Another advantage of masterbatch is its ease of handling. Pigments are a highly volatile powder and more complex to work with and in many cases require the use of personal protective equipment (PPE) to guarantee the health and safety of those who handle them, while masterbatch is easier to introduce into the turbo mixer since it is non-volatile and does not give off powder dust during handling.
High colour uniformity for PVC
Masterbatch leads to very high colour uniformity in the manufactured parts. Due to their nature, when working with pigments, each production batch is different and results in a slightly different tone. Due to this intrinsic property of pigments, the final colour obtained is slightly different and in the vast majority of cases the colour of different production batches is not identical.
Meanwhile, during the manufacture of the colour masterbatch for PVC, the necessary pigmentary adjustment is carried out to ensure colour uniformity during the manufacture of the final parts. These adjustments made by the masterbatch compounder in these cases ensure that the final processor has a product that provides colour uniformity between different production batches, while avoiding changes in the formulation (in terms of colour) during the preparation of any new batch.
In this regard, each time a masterbatch is manufactured, the formula is adjusted to avoid any colour variation with respect to the customer’s specifications. This saves time during the colour adjustment and reduces the number of internal non-compliant products.
Masterbatch: exceptional resistance and sustainability
Masterbatch opens up new markets thanks to its ability to produce colours with exceptional weatherability. This is an important requirement for products such as coloured exterior rigid profiles, PVC films for coating windows, exposed PVC hoses and outdoor live electrical cables. Since the use of masterbatch can also provide a wide range of colours and colour uniformity, processors can meet the requirements of markets that are very demanding in terms of the product’s final appearance.
Masterbatch compounders work with a wide range of pigments that have been previously assessed to determine how they perform outdoors. This know-how allows them to create formulations that ensure non-discolouration of the final product during its useful life.
The use of masterbatch contributes to sustainability in the PVC parts manufacturing industry, since it reduces the discarded product during colour adjustment to practically zero, and also eliminates all internal non-compliant product for colour deviation reasons, derived from possible human errors during the weighing process of the pigments involved in the final colour formulation.
In addition, thanks to the selection of suitable pigments with good outdoor performance, it is possible to extend the useful life of the products, with the consequent reduction of their environmental impact. Delta Tecnic recommends that companies that use pigments for PVC colouring take advantage of masterbatch in their production processes to improve their efficiency and reduce their environmental impact.