Additive | Antistatic

Antistatic Masterbatch

Antistatic 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.

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 masterbatch carrier must be identical/compatible with the polymer. For example, EVA or LDPE is a compatible carrier with polyolefins and nylon, as is polystyrene with 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.

Antistatic Masterbatch | Transformation processes

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

Electrostatic charges are typically caused by friction between two materials Static charging can disturb the continuity many processes. E.g. Static charging can hinder the opening of the tubular film during packaging processes. Often the static charging is the limiting factor for higher speed in these processes. In addition, a reduced static charging avoids dust pick up by the packed goods. As a result, the materials can be stored and eventually displayed in a more attractive way.

Internal antistatic additives are incorporated in the polymer matrix. The controlled incompatibility causes migration to the surface. There it forms a polar layer that absorbs water from the atmosphere. This layer is able to conduct / dissipates the charges (higher conductivity/ lower resistance and shorter charge decay time).

Important here is a balanced incompatibility to control the migration: a too high incompatibility gives a low anti-static performance, a too high incompatibility causes a greasy surface.

An alternative is the addition of conductive fillers as carbon black. These creates a conductive path in the matrix. Here no migrating additives are used. The anti-static properties are stable in time.

Contact us.