Polyurethane-modified bitumen sheet material and method for protective moisture barrier

摘要

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