Conductive molding composition

In a high density information recording medium, adapted for use with a playback stylus to effect recovery of signals occupying a bandwidth of at least several megahertz when relative motion at a desired rate is established between said recording medium and said stylus, said recording medium comprising a disc of molded plastic material comprising a vinyl chloride/vinyl acetate copolymer containing a sufficient amount of finely divided conductive carbon black particles such that the material has a bulk resistivity below about 500 ohm-cm. at 900 MHz and having an information track constituted by a surface relief pattern in said track whereby said signals are recovered upon establishment of said motion at said rate, the improvement which comprises adding to said plastic material a modifying additive comprising a three-component blend of polyvinyl chloride, a graft copolymer of acrylonitrile, styrene and polybutadiene and a copolymer of alpha-methyl styrene and acrylonitrile in an amount of from about 3 up to about 20 percent by weight of the total molding composition, said amount being sufficient to improve the dimensional stability of said recording medium.