Bond strength depends on surface preparation and adhesive type. Plastic film can be manufactured from almost any resin, but not every resin produces an engineering film. Manufacturers can choose from, and end users can specify, a range of process treatments that significantly enhance heat stability, mechanical properties, electrical characteristics, barrier properties, and bondability. Coatings are typically applied by emulsion, solvent, and dry methods. Some processors have developed proprietary antistatic coatings that are cured by electron-beam radiation.
Metal coatings produce conductive capabilities and also enhance barrier properties.
Often, metallization is used to improve moisture-barrier properties for biaxially oriented nylon and polypropylene. Several methods may be used. Corona discharge techniques position the film between an electrically grounded roller and a high-voltage electrode. In gas-plasma surface treatments, film is placed in a reaction chamber. After evacuation, the chamber is charged with oxygen, argon, helium, or nitrogen while a radio-frequency field ionizes the gas.