Polyolefin thermoplastic roofing membranes with improved burn resistivity
A multi-layered thermoplastic roofing membrane comprising a planar body including at least three layers, said at least three layers including (i) a top layer that includes magnesium hydroxide dispersed within a thermoplastic resin, (ii) an upper middle layer disposed below said top layer and including magnesium hydroxide and calcium carbonate dispersed within a thermoplastic resin, and (iii) a lower layer disposed below said upper middle layer and including magnesium hydroxide and calcium carbonate dispersed within a thermoplastic resin.
1. A multi-layered thermoplastic roofing membrane comprising:
a planar body including at least three layers, said at least three layers including
(i) a top layer that includes magnesium hydroxide dispersed within a polyolefin-based thermoplastic resin,
(ii) an upper middle layer disposed below said top layer and including magnesium hydroxide and calcium carbonate dispersed within a polyolefin-based thermoplastic resin, and
(iii) a lower layer disposed below said upper middle layer and including magnesium hydroxide and calcium carbonate dispersed within a polyolefin-based thermoplastic resin.
2. The roofing membrane of claim 1 , where the membrane includes a reinforcement disposed between said upper middle layer and said lower layer.
3. The roofing membrane of claim 1 , where the top layer includes from about 20 to about 50 wt % magnesium hydroxide based upon the entire weight of the layer.
4. The roofing membrane of claim 1 , where the top layer includes from about 30 to about 40 wt % magnesium hydroxide based upon the entire weight of the layer.
5. The roofing membrane of claim 1 , where top layer is devoid of calcium carbonate.
6. The roofing membrane of claim 1 , where the upper middle layer includes from about 10 to about 40 wt % magnesium hydroxide based upon the entire weight of the layer.
7. The roofing membrane of claim 1 , where the upper middle layer includes from about 10 to about 50 wt % calcium carbonate based upon the entire weight of the layer.
8. The roofing membrane of claim 1 , where the lower layer includes from about 0 to about 6 wt % magnesium hydroxide based upon the entire weight of the layer.
9. The roofing membrane of claim 1 , where the lower layer includes from about 25 to about 75 wt % calcium carbonate based upon the entire weight of the layer.
10. The roofing membrane of claim 1 , where the top layer includes less than 3 wt % calcium carbonate based upon the entire weight of the layer.
11. The roofing membrane of claim 1 , where the top layer and the upper middle layer are co-extruded layers.
12. A roof system comprising:
a substrate and thermoplastic membrane affixed to the substrate, where the thermoplastic membrane is a planar body including at least three layers, said at least three layers including
(i) a top layer that includes magnesium hydroxide dispersed within a polyolefin-based thermoplastic resin,
(ii) an upper middle layer disposed below said top layer and including magnesium hydroxide and calcium carbonate dispersed within a polyolefin-based thermoplastic resin, and
(iii) a lower layer disposed below said upper middle layer and including magnesium hydroxide and calcium carbonate dispersed within a polyolefin-based thermoplastic resin.
13. The roof system of claim 12 , where the substrate is selected from the group consisting of a roof deck, an insulation board, a cover board, and an existing membrane.
14. The roof system of claim 12 , where the thermoplastic membrane includes first and second opposed planar surface with one of the opposed planar surfaces being adhered to the substrate.
15. The roof system of claim 12 , where at least 50% of the at least one planar surface of the membrane is adhered to the substrate.
16. The roof system of claim 12 , where the membrane is adhered to the substrate through a polyurethane adhesive.
17. The roof system of claim 12 , where the membrane is adhered to the substrate through a pressure-sensitive adhesive.