Disclosed are highly filled
thermoplastic olefin compositions and, in particular,
thermoplastic olefin compositions that comprise propylene / alpha-olefin copolymers and a high level of organic or
inorganic filler. Specifically, the description addresses a filled
polymer composition comprising: (a) a first
polymer component comprising propylene
copolymer having a heat of fusion < about 75 J / g and a triad
tacticity of from about 50% to about 99%, the first
polymer component having a melt flow rate at 230° C. ≦ about 800 g / 10 min.; and (b) at least about 15% by weight of a filler, based on the total weight of the filled composition. Such compositions are useful as sound barriers,
flame retardant compositions, roofing membranes, and the like.