Additive | Desiccant

Desiccant Masterbatch

Desiccant Masterbatch consists of a concentrated mixture of pigments and/or encapsulated additives manufactured by heating a carrier resin and then cooling it and cutting it into granules. The masterbatch thus allows the transformer to colour and give characteristics to the natural polymer economically in the plastics transformation process.

Desiccant Masterbatch | Technical Advantages | Shelf Life

• Prevents problems of agglomeration of additives or colourants as well as dispersion problems.
• Does not contain solvents and therefore has a longer shelf life.
• Contains an average of 40-65% additive, but the range can reach 15-80% in extreme cases.
• A 25kg bag processes up to one tonne of raw material. Thus, the relatively dilute nature of the materbatches allows for greater precision when dosing small quantities.

Carrier and Dosage

The carrier of the masterbatch should be identical/compatible with the polymer. For example, EVA or LDPE is a carrier compatible with polyolefins and nylon, just as polystyrene is used as a carrier for ABS, SAN and sometimes polycarbonates.

In this sense, when the masterbatch carrier is incompatible with the raw material, changes may occur in the properties of the processed material. The processor must specify the characteristics of the raw material. The percentage of use of masterbatches in relation to the raw material is between 1 and 5 %. Colour and additive masterbatches can be combined.

Adverse effects

• Adverse effects sometimes occur, such as the masterbatch separating from the raw material in the machine hopper.
• The masterbatch, solid or liquid, is added directly to the machine spindle via a peristaltic pump.
• The use of liquid masterbatches also makes it possible to obtain highly precise dosages and rapid colour changes between production runs.

Desiccant Masterbatch | Transformation processes

Masterbatches are compatible with most processes, with the exception of rotational moulding, plastisol and other liquid resin systems.

Desiccant masterbatch can counter problems which develop during the processing of plastics due to the presence of moisture. Moisture can be present in raw materials such as hygroscopic polymers, fillers and pigments. Reclaim and recycled polymer can also have a high moisture content.

When processing polymer with a high moisture content the polymer can become porous and show voids in moulded articles or extruded sheet. In film applications the high moisture content can lead to lensing and film bubble breakage.

Desiccant masterbatch chemically binds moisture during processing and allows higher levels of reclaim or recycled polymer to be used; addition of higher filler levels; and can reduce the need for pre-drying in many applications. Polybatch desiccant offers a simple and cost effective solution to solve moisture problems.

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