Patent ID: 7459180

Claim:
A process for making a waterproofing membrane for a roof surface comprising: providing a carrier sheet constructed of a plastic film, woven fabric, or nonwoven fabric, said carrier sheet having a first major face which, in use, will be exposed to foot traffic and a second major face which, in use, will be adhered to a roof surface; providing on said first major face of said carrier sheet a skid-resistant polymer in a repeating pattern of shapes by depositing said polymer through a transfer process comprising (A) contacting said polymer upon a circumferential surface of a gravure roll having a cylindrical body, said circumferential surface having an image portion and a non-image portion, said image portion defined by a plurality of cell openings etched, incised, or indented into said circumferential surface, said plurality of cell openings having at least two different average depths, and (B) wiping said circumferential surface continuously with a doctor blade whereby said gravure roll is operative to transfer in one step onto said carrier sheet first major face (i) a continuous base coating formed by residual polymer wiped by said doctor blade against said non-image portion of said circumferential surface and (ii) a pattern formed by polymer wiped into said plurality of cell openings of said image portion by said doctor blade; and thereafter applying a coating of finely divided particulate material to said polymer deposited on said carrier sheet first major face, and attaching on said second major face of said carrier sheet a self-adhesive, continuous bituminous or synthetic waterproofing adhesive layer operative to adhere said second major face to a roof surface and provide a moisture seal, said waterproofing adhesive layer having a thickness no less than 5 mils and no greater than 100 mils, and wherein said skid-resistant polymer on said first major face is operative to provide skid-resistance to foot traffic when said waterproofing membrane is installed on a roof surface.