Patent ID: 6713726
Filing Date: 2004-03-30
Classification: B29C,B29K,B29L,B32B,Y10T

Abstract:
A heat-sealing method comprising the steps of:feeding a fusible fiber sheet composed of a nonwoven fabric and a layer of long fibers opened from tow into a clearance between a pair of rolls, at least one of which has sealing ridges of a predetermined pattern on its outer circumference; and heating and pressing said fiber sheet with said sealing ridges, to form fused portions corresponding to the pattern of said sealing ridges, in said fiber sheet, wherein an insulator is disposed to cover the outer circumference of said rolls, as lacking said sealing ridges, and is made of a material which has a lower thermal conductivity than that of said sealing ridges and which can be elastically contracted by a pressure of said rolls, and said insulator has a thickness, when unexposed to the pressure of said rolls, which is larger than a height of said sealing ridges; and wherein when fed into the clearance between said rolls when rotating, the fiber sheet is compressed by said insulator to discharge its internal air and is then heated and pressed by said sealing ridges so that it is heat-sealed.