Patent ID: 6732488
Filing Date: 2004-05-11
Classification: B29C,B29K,B29L

Abstract:
A sealing device for a packaging material for overlapping layers of plastic sheets to be sealed, the layers of plastic sheets facing each other, pressuring the layers of plastic sheets from the an outside with a sealing bar, and pressing the layers of plastic sheets to be sealed by a predetermined sealing width, while the layers of plastic sheets are in a melting state, comprising:a linear sealing device for pressuring the layers of plastic sheets to be sealed with a pressuring portion of a sealing bar having a width narrower than the predetermined sealing width, said linear sealing device pressuring the layers of plastic sheets to be sealed, while the layers of plastic sheets are in a heated state; and a surface sealing device disposed subsequent to the linear sealing device, for pressuring the layers of plastic sheets to be sealed including the part pressured by the linear sealing device with a pressuring portion of a sealing bar having a width necessary for forming the predetermined sealing width, said surface sealing device pressing an entire region of the layers of plastic sheets to be sealed, while the layers of plastic sheets are in a melting state, wherein the melting temperature of the layers of plastic sheets to be sealed at the time of pressing by the surface sealing device is an extrapolated melting end temperature or more of the plastic comprising the layers of plastic sheets to be sealed.