Foamed polypropylene sheet having improved appearance and a foamable polypropylene composition therefor

A foamable polymer composition comprising a monomodal polypropylene resin having a melt flow rate of from about 0.3 to about 10 g/10 min. determined according to ASTM D1238 condition L and having an isotactic index greater than 0.92, said resin having dispersed therein from about 0.05 to about 0.5 wt. % of a crystallization nucleating agent selected from the group consisting of sodium bis(4-tert-butyl-phenol)phosphate and sodium benzoate, from about 0.01 to about 5 wt % of a finely divided talc having a mean particle size in the range of from about 0.3 to about 5 microns, and from about 0.1 to about 10 wt. % of a non-physical foaming agent.

A foamable polymer composition comprising a monomodal polypropylene resin having a melt flow rate of from about 0.5 to about 4 g/10 min. determined according to ASTM D1238 condition L, said resin having dispersed therein from about 0.05 to about 0.5 wt. % of a sodium benzoate crystallization nucleating agent, from about 0.01 to about 5 wt. % of a finely divided talc having a mean particle size in the range of from about 0.3 to about 5 microns, and from about 0.1 to about 25 wt. % of a foaming agent.