Patent ID: 6174576
Filing Date: 2001-01-16
Classification: B32B,B65D,Y10T

Abstract:
An element with a determined gas permeability, said element comprising a first layer and a second layer connected the one to the other by a welding zone wherein the first layer and the second layer are welded together with interposition of a band of fibres at welding points, the fibres of the band having a melting temperature at most 5.degree. C. higher than the melting temperature of at least one of said layers, whereby, at the welding points of the welding zone, fibres of the band are molten into the welding points, while between two adjacent welding points of the welding zone, fibres of the band are not molten, whereby a plurality of adjacent welding points are formed and separated the one from the other so as to form, in the band of fibres of the welding zone, channels for the exchange of gases through the fiber band, while avoiding the passage of solid particles through the fiber band.