Method and apparatus for controlled triggering of oxygen scavenging compositions utilizing a wrap-around shade

An apparatus for activating a web having an oxygen scavenging composition, comprising:

• a plurality of UV lamps arranged in a bank and disposed in a UV chamber, the bank of UV lamps having first and second sides through which UV light is transmittable;
• a series of guide rolls disposed in said UV chamber and defining a web pathway for directing the web in close proximity with the first and second sides of the bank of UV lamps;
• and
• a retractable and extendable UV shade arranged to wrap about the first and second sides, the UV shade being configured to move between open, partially open, and closed positions so that the dosage of UV light to which the web is exposed is controlled by adjusting the degree to which the shade is open.

A system for activating a film having an oxygen scavenging composition, the system comprising:

• a roll of unactivated film having an oxygen scavenging composition that is in an unactivated state;
• a UV chamber for activating the film, the UV chamber having
• an inlet through which unactivated film enters the UV chamber;
• a plurality of UV lamps arranged in a series and disposed in the UV chamber, the series of UV lamps having first and second sides through which UV light is transmittable;
• a plurality of guide rolls disposed in said UV chamber and defining a film pathway for directing the film in close proximity with the first and second sides of the series of UV lamps so that the oxygen scavenging composition is activated by being exposed to UV light;
• a moveable UV shade that is capable of wrapping about the first and second sides, the UV shade being configured to control the dosage of UV light to which the film is exposed by adjusting the degree to which the UV shade is open;
• a shade drive system operable to move the UV shade between varying degrees of openness;
• an exit through which activated film may exit the UV chamber;
• a drive roll for driving the film along the film pathway through the UV chamber;
• and
• a control unit that is operatively connected to the shade drive system and the drive roll, the control unit being configured to instruct movement of the UV shade so that the dosage of UV light to which the film is exposed is controlled by adjusting the degree to which the UV shade is open and by adjusting the speed of the film as it travels through the UV chamber.

A method of controlling the UV dosage to which a film having an oxygen scavenging composition is exposed, the method comprising:

• providing a film having an unactivated oxygen scavenging composition;
• passing the film through a UV chamber, wherein the UV chamber includes a UV light source and a moveable UV shade that is capable of being at least partially disposed between the UV light source and the film;
• exposing the film to the UV light source for a sufficient amount of time to activate the oxygen scavenger;
• controlling the dosage of UV light to which the film is exposed by adjusting the degree to which the shade is disposed between the UV light source and the film;
• and
• supplying the activated film to a packaging system.