Thermoplastic filled membranes of propylene copolymers

A thermoplastic membrane formed from a blend of:

• a) from 35 to 96 percent by weight of a semicrystalline first polymer component (FPC), wherein said FPC comprises a propylene-ethylene copolymer containing from 80 to 93 percent by weight of units derived from propylene, and having a melting point derived from stereoregular polypropylene sequences, as determined by differential scanning calorimetry (DSC), in the range of from 25° C. to 70° C., and a heat of fusion of from 2 J/g to 25 J/g;
• b) from 1 to 40 percent by weight of an inorganic filler;
• c) from 1 to 25 percent by weight of a processing oil;
• and
• d) from 2 to 35 percent by weight of a crystalline second polymer component (SPC), wherein said SPC is a stereoregular polypropylene containing less than 7 percent by weight of units derived from ethylene or alpha-olefin monomer containing from 4 to 8 carbon atoms and having melting point, as determined by DSC, greater than 130° C., and a heat of fusion greater than 80 J/g;
• wherein the sum of components in said blend is 100 percent, said membrane having the following properties:
• 1) tensile strengths≧0.1×(Shore A hardness-60)+2
• 2) tear strength (Die C)≧Shore A hardness-60, and
• 3) tack≧0.25×(Shore A hardness-60).