The outstanding characteristics of PP are its high resistance to fat and oil which is why it is the preferred packaging material for dairy. Its imperviousness to water vapour & its excellent frost resistance is a useful benefits especially welcomed for frozen food packaging. Depending on the type of material a PP tray can even be transferred directly from the freezer to the microwave and heated without suffering any damage. Trends in PP packaging are moving towards the use of highly crystalline extremely rigid PP homopolymers for further reduction of wall thickness in packaging with simultaneous high heat resistance and a further improved water vapour barrier.