Patent ID: 7618700
Filing Date: 2009-11-17
Classification: B32B,E04D,Y10T

Abstract:
1. A film-bitumen combination comprising of at least three layers wherein said at least three layers comprise a bituminous layer and at least two film layers made from different materials, said bituminous layer being coated on said at least two film layers; said at least two film layers comprise a first film layer and a second film layer produced from a polyolefin, polypropylene, polyamide, polyethylene terephthalate (PET), or polyacrylonitrile; said first film layer being located further away from said bituminous layer and having a larger coefficient of thermal expansion than said second film layer; wherein at least a first edge of said at least two film layers projects beyond the bituminous layer and at least a second edge of said at least two film layers is shorter than the bituminous layer; wherein a surface of a side of the combination facing away from the bituminous layer has been treated to have non-slip properties; wherein each individual film layer is arranged in the combination in accordance with its thermal stability and its mechanical strength; a barrier layer against mineral oils, oxygen or UV radiation disposed between the bituminous layer and two adjacent layers of said at least two film layers; and wherein said barrier layer consists of a layer of lacquer; and wherein the phenomenon known as curling which occurs with a symmetrical structure no longer occurs with said film-bitumen combination.