Through its close relationship with Masterbatch producers, such as Colourtone, Plastribution is able to offer a very comprehensive range of Masterbatch products including colour additive & flame retardant in quantities ranging from a few kgs to full trucks.

With this facility customers can combine Masterbatch and polymer deliveries giving them the potential to save time, effort, & money. Injection moulding, blow moulding, profile extrusion, sheet extrusion, film extrusion, cast film, fibres and calendered sheet processes commonly employ masterbatch. Why? Because masterbatch offers processors an easy and convenient way of adding colour and/or performance-enhancing additives to natural or base polymers on their own plant.

A masterbatch is a solid concentrate of colour and/or performance enhancing additives such as anti-static, UV stabiliser and metal deactivator, added to a base polymer. It is usually supplied in granular form, either as pellets similar in size to most polymers or as miniature pellets, known as micro-granules. Alternatively, masterbatch can be delivered in 'rough cut' form - a mixture of small shreds and chunks.

Two main types are offered: polymer specific and universal.

Polymer specific masterbatch is produced using the same base polymer group as the type being used by the processor. Universal masterbatch employs a carrier system that is capable of carrying the high quantities of additives necessary to deliver the end use properties required, as well as affording the essential compatibility required across a broad range of polymers. Universal masterbatches are normally readily available from stock in small quantities and have proved cost-effective if used correctly. However, in terms of compatibility, they can be considered a compromise and processing difficulties sometimes arise with some materials, and engineering polymers that may have to be pre-dried. They are not usually recommended for use at high dosage levels as the appearance or physical properties of the final product may be adversely affected. Conversely, polymer specific masterbatch can be pre-dried with the host polymer and added at high loading without compatibility problems.

The application almost always influences the type of masterbatch chosen. Only a limited range of colours are generally available and not all engineering polymers lend themselves to conversion to masterbatch. Toys and food packaging, for example, have to be produced from materials made with 'controlled' ingredients and engineering products demand reliable high performance properties. Other typical determining factors might be service conditions such as weatherability or light-fastness. In simple terms, manufacture is a two-stage process: gathering ingredients and then mixing them together by applying heat and shear to produce a homogenised pellet. Generally, high or low speed mixers are used to produce a pre-mix of the additives, which is then compounded on roller mills, kneaders or single or twin screw extruders. Even distribution (dispersion) and development (breaking down) of the additives throughout the carrier are essential. This processing depends on several key elements: formulation, quality of raw materials, quality of mixing and compounding plant. Finally, the finished masterbatch is pelletised (die-face or strand-cut) or ground.

Masterbatch, available from Plastribution, can be introduced to the processor's base polymer on the production line in a number of ways, the most successful methods being volumetric or graviametric dosing. In both techniques, the masterbatch is added directly into the polymer stream immediately before processing.