Pelander, Richard (Sikurimyllyntie 5 A Helsinki, FIN-00370, FI)
[0002] The roofing membrane of the invention can be used as a primer and/or a topping sheet.
[0003] The roofing membrane of the invention can be manufactured from blown bitumen, bitumen modified with rubber or plastic, or from suitable plastic material. The reinforcement layer of the roofing membrane can be of polyester (basis weight being e. g. 80 to 350 g/m2) or glass fibre (basis weight being e. g. 40 to 200 g/m2) or wood fibre or textile felt (basis weight being e. g.
100 to 600 g/m2) or combinations thereof.
[0004] The stripes of the protective layer can be of plastic or metal, or of fluid, e. g. sprayable, substance or combinations thereof.
[0005] The structure of the roofing membrane of the invention is known per se, but the lower surface of the roofing membrane is covered throughout with a continuous welding bitumen layer the surface of which has a protective layer comprising stripes. A first stripe (A) is of welding plastic or the like, which melts as heated with a torch or a hot-air blower, whereby the weld- ing bitumen beneath the stripe simultaneously melts and the roofing mem- brane adheres to its base. A second stripe (B) is of material that does not melt but acts as a permanent protective layer, so the welding bitumen beneath said material does not melt nor adhere to the base in these areas. The material of the stripe (B) can also otherwise prevent the welding bitumen from melting.
[0006] The roofing membrane of the invention is manufactured by providing the lower surface of the roofing membrane known per se with a con- tinuous welding bitumen layer that is protected with said protective layer.
[0007] The advantages of the roofing membrane of the invention: [0008] there is no need to provide the lower surface of the roofing membrane with separate welding bitumen stripes or welding bitumen patterns (e. g. diamond patterns, circles or squares) or the like, which add to the thick- ness of the roofing membrane and increase the manufacturing costs; [0009] the seams of the roofing membrane can be joined by re- moving from the end area of the roofing membrane the plastic with a higher melting point and by heating the welding bitumen; [0010] the roofing membrane manufactured by means of a novel 5 membrane has an even surface ; [0011] thanks to the novel method, a thinner reinforcement layer can be used in the roofing membrane without the surface being uneven.
[0012] Figure 1 shows a protective layer which consists of alternat- ing stripes (A) and (B).