Antifogging 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.
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.
Masterbatches are compatible with most processes, with the exception of rotational moulding, plastisol and other liquid resin systems.
The term “fogging” refers to the condensation of water vapor on a plastic film’s surface. This results in the formation of water droplets. In food packaging films the droplets makes the content less visible and may decrease the quality of the packed product.
In agricultural applications as greenhouses, fogging will affect the transmittance of light, causes burns of the crops by the lens effect of the droplets, and a continuous water drip. Typical polyolefins are very hydrophobic. Water on a film surface will cause the formation of droplets (high contact angle: no wetting or spreading of the water over the surface).
The addition of (internal) anti-fogging additive makes the surface more polar. They have a controlled incompatibility with the polymer. This causes a migration to the surface of a plastic film. There it is responsible for a polar layer at the surface. This increases the surface energy. The difference between the surface energy of the plastic surface and the water reduces, thus the contact angle reduces. The water spreads out as a thin film, instead of forming thick drops The optical properties remain less affected.