Rhone-poulenc Chimie

Alain Morin

Jean-Pierre Quentin

Claude Bonnebat

Molding compositions, easily shaped into useful articles having improved mechanical properties that are less anisotropic, contain (a) a thermotropic polymer, and (b) an inorganic filler material, such inorganic filler (b) being a crystalline inorganic filler of platelet shape having a mean diameter ranging from 0.5 to 400 .mu.m and a shape factor represented by the ratio: ##EQU1## which ranges from 10 to 90, and such inorganic filler (b) being present in an amount, expressed in % by weight of filler in the combined polymer+filler, ranging from 20% to to 60%, with the proviso that such amount ranges from above 50% to 60% when the mean particle diameter of the filler material is less than 20 .mu.m.

Thermotropic polymer/inorganic reinforcing filler molding compositions

Smooth, thin, dimensionally stable, essentially circular and planar injection-molded disc members, well adapted as substrates for magnetic recording discs, e.g., by providing same with an effective recording amount of a magnetic coating material on at least one of the face surfaces thereof, comprise a radially molecularly oriented thermotropic polymer, desirably having a flow temperature ranging from 200.degree. C. to 350.degree. C. and an inherent viscosity of at least 1 dl g.sup.-1.

Highly oriented thermotropic magnetic recording medium

Rigid, dimensionally stable, essentially circular and planar, axially injection-molded disc members, well adapted as support substrates for radiation sensitive layers for optical discs, e.g., laser discs, comprise radially molecularly oriented thermotropic polymers and such disc members have a radiation-sensitive microrelief pattern on at least one of the face surfaces thereof.

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Villeurbanne, France

Alain Morin