Film packaging that can easily be pulled off the bottom film or allows opening without tearing or cutting open the packaging (easy opening).
The ability of gases and vapours (oxygen, carbon dioxide, flavourings, solvents and steam) to pass through the undamaged packaging surface; an important variable for films.
Property of films used for food packaging; raw materials and additives used must be approved for use in food products.
Polypropylene (PP) is a semi-crystalline thermoplastic and belongs to the polyolefin group. Features: Very low water absorption, very low water vapour permeability, high gas permeability, poor cold resistance of unstretched film, high abrasion resistance, very low cold flow, very high elasticity in some cases, very high transparency. PP comes from the polymerisation of propylene (colourless gas). It is obtained by thermal cracking of benzines accrued during the processing of crude oil. PP is suitable for injection moulding, extrusion, blow moulding, hot working, welding, deep-drawing, machining or manufacturing particle foam.
Properties of polypropylene: - Has very high shock and impact resistance; - Has a lower self-weight than materials such as PE; - Features high rigidity, hardness and strength; - More UV resistant than materials such as PE and permanently retains its properties (PE loses its physical properties after a certain amount of time); - Is odourless, does not irritate the skin and is suitable for food; - Is non-toxic; - Has a higher glass transition temperature than PE; - Does not become brittle until temperatures below -10 °C; - Has a higher rigidity, hardness and strength than polyethylene; - Has a glass transition temperature of 0 °C to -10 °C, becoming brittle in cold temperatures; - Upper working temperature is between 100 - 110 °C; - The crystallite melting range is between 160 - 165 °C; - Can be loaded with mineral filling materials such as talc, chalk or glass fibres, which significantly expands the range of mechanical properties (rigidity, working temperature, etc.); - Is resistant to alcohols, organic solvents and fats, however not resistant to petrol, benzene and other volatile hydrocarbons; - Readily dissolves in xylene, tetralin and decalin as well as other solvents, particularly mineral oil-based solvents, at higher temperatures; - Is odourless and does not irritate the skin, is suitable for applications in the food and pharmacy sector, non-toxic.