US Patent 8663413 White and black ply laminate and methods

According to one embodiment, a method of making a roofing membrane is provided. According to the method, an ethylene propylene diene monomer rubber (EPDM) material sheet is provided and a thermoplastic polyolefin (TPO) material sheet is extruded onto the EPDM material sheet. The EPDM material sheet and TPO material sheet are then pressed together via one or more rollers. The EPDM material is uncured and has a thickness of between about 50 mils and 70 mils. The extruded TPO sheet has a temperature of at least 150 degrees Celsius and a thickness of between about 15 mils and 35 mils. The heat of the TPO material sheet causes a top portion of the EPDM material sheet to cure such that crosslinking of the TPO and EPDM material sheets occurs at an interface of the sheets to bond the sheets together.