Patent ID: 6436471
Filing Date: 2002-08-20
Classification: B32B,D04H

Abstract:
A process for coating a sequence of spaced apart multi-sided mineral fibre base layer mats carried on a conveyer with a surface coating in the form of a fibrous non-woven fabric formed of a thermoplastic polymer material on more than two surfaces of each mat to form a mineral fibre element, the process comprisingmelting the thermoplastic polymer material and supplying the polymer melt obtained to a plurality of coating stations arranged in sequence along the conveyer and including a final coating station, each coating station comprising a single coating device comprising a number of dispensing units comprising a number of orifices disposed so as to coat only a single surface of a mat, and at each coating station in the sequence extruding the polymer melt through the orifices of the coating device of that coating station to distribute the extruded polymer material on one surface only of a mat while directing one or more pressurized gas streams closely past the orifices thereof in order to elongate the extruded polymer material so as to form thin filaments or fibres or both, and after the polymer melt distribution on that surface is complete, moving the mat on the conveyer from that coating station to the next sequential coating station, and extruding the polymer melt through the orifices of the coating device of said next coating station to distribute the extruded polymer material on another one surface only of the mat while directing one or more pressurized gas streams closely past the orifices thereof in order to elongate the extruded polymer material so as to form thin filaments or fibres or both, and after the polymer melt distribution is completed at the final coating station, moving each coated mat on the conveyor away from the final coating station, wherein each coating device is spaced from any other coating device sufficiently so as to substantially avoid interfering of gas streams of adjacent coating devices.