Patent ID: 7666491

Claim:
A single-ply roofing membrane, comprising a thermoplastic polyolefin-based mixture that includes: a thermoplastic polyolefin blend consisting of 20 parts of a first polypropylene-ethylene elastomer having a first ethylene co-polymer in an amount of 15 percent by weight of said first elastomer and 80 parts of a second polypropylene-ethylene elastomer having a second ethylene co-polymer in an amount of 12 percent by weight of said second elastomer, wherein said amount of said first co-polymer in said first elastomer is different from said amount of said second co-polymer in said second elastomer; titanium dioxide in an amount in the range of about 5 to about 10 parts per 100 parts of said blend; and calcium carbonate in an amount in the range of greater than 0 to 80 parts per 100 parts of said blend, wherein said roofing membrane consists of a non-reinforced single layer of said thermoplastic polyolefin-based mixture, wherein said roofing membrane is heat-weldable, wherein a sample of said roofing membrane having a thickness of 30 mil has a stretchability of 24 lbf as measured by the stretchability test, and wherein said roofing membrane has a whiteness of at least an L* value of 90 as measured by the whiteness test.