| abstract |
A modified bitumen sheet material (12) and method for a protective moisture barrier, particularly for masonry surfaces (42). The sheet material has a bitumen layer (14) modified by the addition of a minor amount of a long-chain polybutadiene-isocyanate urethane polymer and optionally, a modifying amount of hydrocarbon oil to provide stable, non-flow and selected tackified surface properties to the bitumen layer (14). The sheet material (12) includes a releasable casting paper film (16) on one surface of the bitumen layer (14), to be removed prior to use, and a cross-linked polyethylene film (12) bonded to the other outer surface of the bitumen layer (14) as a handling or moisture barrier sheet. The sheet material (12) is prepared by casting the hot, melted bitumen as a layer (14) onto a casting paper sheet (16) and applying the outer film to the exposed bitumen surface to bond to the top surface. |