Press forming method of corrugated paperboard into curved board - includes preheating before planar board introducing board into hot press, enabling board softening before contacting stationary die

摘要

The method is for press-forming a planer board of corrugated paperboard into an at least partly curved board by means of a hot press fitted with stationary and movable dies respectively having suitably shaped die faces. The corrugated paperboard of the type utilizing a thermoplastic resin as the adhesive to bond paper liners to a corrugated paper medium. The method includes the steps of heating the stationary die and then pressing the planar board against the die face of the heated stationary die by the heated movable die. The improvement comprising the step of preheating the planeer board before the placement of the planer board on the heated stationary.