Expert knowledge from A-Z
Water vapour resistance
Water vapour permeability specifies the amount of water vapour in "g/m² x d", which diffuses through a 1 m² test surface in 24 hours (d) at a defined humidity and temperature. Low water vapour permeability protects products from drying out. Test standard: DIN 53122.
Weight per unit area
Weight of the film per unit area (g/m²). The weight per unit area of films depends on the density of the raw material and the thickness of the film.
A method for combining the films used in packaging technology. Contact sealing: Using a (continuously heated) heating rod and counter-pressure bar. Pulse sealing: A sealing bar receives the necessary energy only for a short period of time. Continuous heat welding: Two (endless) moving belts are pressed together by heated sealing bars. Hot-wire welding: Films are simultaneously welded and separated with a heated wire; together with a welding bar, this is also known as separated seam welding. High frequency welding: Heat is generated by a radio frequency field. Ultrasonic welding: The pressure from the mechanical vibrations of ultrasonic frequencies is converted into heat at the contact surface of the films and creates the seal.