Polypropylene
Temperature range: -18ºC up to 100ºC
Ideally suited for Microwave packaging. “From the Freezer to the Microwave”.
Polypropylene or polypropene (PP) is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including food packaging, ropes, textiles, plastic parts and reusable containers of various types, thermal pants and shirts made for the military, laboratory equipment, loudspeakers, automotive components, and polymer banknotes. An addition polymer made from the monomer propylene, it is rugged and unusually resistant to many chemical solvents, bases and acids.
Antifog
The term "fog" is used to describe the condensation of water vapour on the surface of a transparent plastic film in the form of small discrete droplets. Physical conditions leading to this phenomenon are:
* A decrease in temperature on the inside of the film below the dew point of the enclosed air/water vapour mixture.
* Cooling of the air near the film to a temperature at which it can no longer retain all water vapour; excess water condenses upon the film.
Internal antifog agents are directly incorporated into plastics to achieve the spreading of condensed water droplets into a continuous and uniform layer of water on the fabricated film.
Internal antifog additives are surface active agents, which have a balanced incompatibility with the polymer matrix. They are added during the extrusion process in pure form, as concentrate or masterbatch. When the film is made they are uniformly dispersed throughout its thickness but they subsequently migrate to the film surface, where they increase the critical wetting tension.
This combined with a partial solubility of the antifog agent in water, which leads to a decrease in surface tension of the water, will significantly diminish the difference between the surface tension of water and the polymer.
