THERMOPLASTIC ROOFING MEMBRANES FOR FULLY-ADHERED ROOFING SYSTEMS

1 . A multi-layered thermoplastic membrane including:

(i) a first layer including first and second coextrudate layers, where the first coextrudate layer includes a thermoplastic polyolefin and from 15 to 50 weight percent magnesium hydroxide based on the entire weight of the first coextrudate layer, and is devoid of a functionalized polyolefin, and where the second coextrudate layer includes a thermoplastic polyolefin, from 33 to 80 weight percent mineral filler based on the entire weight of the second coextrudate layer, and from about 1 to about 20 weight percent of a functionalized polyolefin copolymer based upon the entire weight of the second coextrudate layer, and

(ii) a second layer including a thermoplastic polyolefin, from 33 to 80 weight percent mineral filler based on the entire weight of the second layer, and from about 1 to about 20 weight percent of a functionalized polyolefin copolymer based upon the entire weight of the second layer, said second layer including a planar surface forming an exterior surface of the multi-layered thermoplastic membrane.

2 . The thermoplastic membrane of claim 1 , wherein the second layer includes from about 2 to about 15 weight percent of the functionalized polyolefin copolymer based upon the entire weight of the second layer.

3 . The thermoplastic membrane of claim 1 , wherein the second layer includes from about 3 to about 10 weight percent of the functionalized polyolefin copolymer based upon the entire weight of the second layer.

4 . The thermoplastic membrane of claim 1 , where the first coextrudate layer is devoid of clay.

5 . The thermoplastic membrane of claim 1 , where the thermoplastic polyolefin is a reactor copolymer of ethylene and propylene.

6 . The thermoplastic membrane of claim 1 , where the functionalized polyolefin copolymer is a maleated copolymer of ethylene and an α-olefin.

7 . The thermoplastic membrane of claim 1 , where the mineral filler is calcium carbonate.

8 . The thermoplastic membrane of claim 1 , where the mineral filler is clay.

9 . A roof system comprising:

(i) a roof substrate; and

(ii) a thermoplastic membrane including at least one layer including a thermoplastic polyolefin and a functionalized polyolefin copolymer, where the membrane is adhered to the roof substrate and wherein said at least one layer further includes from 33 to 80 weight percent of a mineral filler based on the entire weight of the at least one layer.

10 . The roof system of claim 9 , where the thermoplastic membrane is characterized, prior to being adhered to the substrate, by a stiffness represented by a flexural modulus of less than 90 MPa, or by a Taber stiffness of less than 15, or by a shore D hardness of less than 40, or by a combination thereof.

11 . The roof system of claim 9 , where at least 50% of at least one planar surface of the membrane is adhered to the substrate.