Method for manufacturing food packaging paper tray that can be easily separated and discarded

A method of manufacturing a paper tray, comprising a stretch film coated thereon, for food packaging that is to be separated from the stretch film and discarded, in which food products can be sealed and packaged through a sealing machine using a thermoplastic film, the method comprises:

• cutting out a paper tray blank in a shape of an unfolded diagram from a base paper of a predetermined thickness,
• the paper tray blank comprising:
• a bottom,
• walls extending from the bottom, each of the walls being foldable along partial cut-and-fold lines disposed between the bottom and the walls, and
• each wall comprising an outward flange being foldable outwardly along a half-cutting line at a top of each wall to serve as an attachment portion for the thermoplastic film;
• folding the paper tray blank to form a paper tray,
• folding comprising:
• placing the paper tray blank over a base mold, the base mold comprising a tray-receiving part having a shape corresponding to an outer shape of the paper tray, and
• pressing the bottom of the paper tray blank downwardly such that the walls are folded upwardly at each side of the bottom while folding the outward flanges from the top of the walls toward the outside to form the paper tray;
• attaching a stretch film to the paper tray using a film attachment mold and a film coating-plug mold,
• the stretch film comprising a sheet of synthetic resin film treated with an adhesive,
• the film attachment mold comprising a first part and a second part,
• the film coating-plug mold being located between the first part and second part of the film attachment mold and comprising a bottom portion with a shape corresponding to an internal shape of the paper tray, and
• the attaching comprising:
• placing the stretch film to cover the paper tray received in the tray-receiving part of the base mold,
• moving the film attachment mold toward to the base mold to press-attach the stretch film to the outward flanges of the paper tray,
• cutting the stretch film along edges of the outward flanges, and
• in a state that the outward flanges are pressed by the film attachment mold and fixed between the film attachment mold and the base mold after attaching the stretch film to the outward flanges, moving the film coating-plug mold toward the base mold to:
• press-down a central part of the stretch film covering the bottom and the walls of the paper tray,
• stretch the stretch film, and
• attach the stretch film to the bottom and the walls of the paper tray;
• and
• ejecting the paper tray coated with the stretch film from the base mold.