Whether consumer goods, cosmetics, luxury items, or industrial goods: Black is considered the colour of choice for many plastics. On the one hand, it is noble and elegant; on the other hand, it stands for coolness and seriousness. In other areas, it looks plain and robust. The Grafe Group, Blankenhain, has been a specialist in the black colouring of standard plastics for many years and has a broad portfolio of corresponding masterbatches. Based on these competencies, solutions are also being developed for more and more technical plastics and their corresponding applications, with the help of which brilliant black tones can be realized.
„In the PE/PP area, we offer a deep black for injection moulding, also known as piano black, which produces a depth of colour that can otherwise only be produced by soluble dyes in amorphous polymer structures. On customer request, the masterbatches can be combined in such a way that flowability and cycle time improve“, reports Danny Ludwig, Head of Product Management, Color & Functional Masterbatches and especially refers to applications in the automotive sector.
With the new Base Black masterbatch for PP, an efficient alternative has also been developed for the most common automotive black shades, which, in addition to its permanent availability - sample quantities are sent out the same day for production tests - also offers a significantly better price level compared to an OEM direct colour. Furthermore, the masterbatch can be flexibly adjusted. It already achieves excellent colour values at standard parameters in the production process, which are within the OEM tolerance and only deviate slightly from the direct colours.
Another product group for which Grafe supplies the ideal colourants are thermoplastic polyurethanes. „For TPUs, we have a wide range of black batches in our portfolio, both for esters and ethers. The degree of filling of the carbon black content here reaches up to 35 percent. In addition to cable extrusion and extrusion, there are also corresponding applications in injection moulding.“, explains Ludwig
The expert also refers to the high-quality and highly-filled styrene batches in the product range. „Here, the degree of filling of the carbon black is up to 30 percent, with an outstanding colour depth in black. The very fine-particle carbon black used to be a challenge that we have now been able to overcome, which can bring various advantages for the customer.“ The colouring is possible in various target polymers, including PC/ABS, PC, PS, SAN, ABS, PA/ABS, SB and SEBS, and the processing has been tested both in injection moulding and extrusion. The packaging sector in particular is an important target industry.
For applications in 3D printing, Grafe also provides a black batch for PLA that is characterised by very good dispersion and homogenisation. „It is very well suited for filament extrusion and impresses with its excellent processability without agglomerates“, reports the head of product management. A masterbatch for PC processing, which is used in injection moulding, also has a very good colour depth and good dispersion quality.
For the production of staple fibres and in film extrusion, Grafe offers a masterbatch that is suitable for black colouring of PET. „It has the usual market carbon black content of 30 per cent with very good dispersion“, so Ludwig. This is necessary in order to be able to colour fibres reliably. Very good carbon black and fibre quality are further special features of the product.
One of the company’s special fields has always been automotive applications. „For injection-moulded parts in the engine compartment where PBT is used, we offer a solution that impresses with excellent homogenisation at low dosage and can also be equipped with improved nucleation on request.“, says Ludwig. „In recent years, we have also increasingly established ourselves as specialists for exterior components made of PMMA and are constantly developing these applications further.“ In addition to the automobile, the expert also considers the construction sector as an important field of application.
For PA processing, Grafe has a wide range of carbon blacks or nigrosine available for black colouring. „The target group here is normal injection moulding applications, especially for automotive, but also technically very demanding components in the construction sector. There are various possibilities for optimising the material quality or the processing procedure“, says the expert, citing improved flowability and nucleation. „In addition, filigree and longer flow paths can be overcome more gently and components can be demoulded and removed earlier.
