Patent ID: 6739367
Filing Date: 2004-05-25
Classification: B29C

Abstract:
A plastic film heat seal apparatus comprising:a heat seal bar covered with at least one low adhesive sheet, said heat seal bar being pressed against superposed layers of plastic film so that said layers of plastic film can be heat sealed with each other by said heat seal bar to have a heat sealed portion whenever said layers of plastic film are intermittently fed in a direction and temporarily stopped, said low adhesive sheet being interposed between said heat seal bar and said layers of plastic film for protection of said layers of plastic film when said heat seal bar is pressed against said layers of plastic film, said heat seal bar being then retreated and spaced from said layers of plastic film to permit said layers of plastic film to be fed again after being heat sealed, said heat sealed portion including upstream and downstream edges in said plastic film feeding direction; loosening means by which said low adhesive sheet is loosened at a position upstream of said heat seal bar in said plastic film feeding direction after said heat seal bar is pressed against said layers of plastic film; and holding means by which said low adhesive sheet is held at a position downstream of said heat seal bar in said plastic film feeding direction, said low adhesive sheet being pulled by and peeled off said layers of plastic film gradually and progressively in a direction to said upstream edge from said downstream edge of said heat sealed portion when said layers of plastic film are fed again after being heat sealed.