Process for producing fiber reinforced foam having a random orientations of fibers

A process for making a fiber-reinforced thermoplastic, said process comprising the steps of:

• mixing a thermoplastic, a foaming agent, and a plurality of discrete expanded reinforcing fibers coated with a coupling agent which enhances bonding between said thermoplastic and the fibers and bonding between the fibers, each fiber exhibiting a length within the range from about 0.5 mm to about 25 mm in an extruder under conditions including:
• (a) sufficient heat and friction within said extruder to melt said thermoplastic and activate said coupling agent;
• and (b) a pressure sufficiently high to prevent premature expansion of said foaming agent, to form a molten, reinforced, unfoamed plastic;
• extruding said molten, reinforced, unfoamed plastic to atmospheric or lower pressure to form an extrudate wherein said fibers have an inherent orientation in said molten plastic induced by the directional shear forces of extrusion as said molten plastic exits the extruder;
• and
• allowing said foaming agent to expand at atmospheric or lower pressure to induce a cellular structure exhibiting a random orientation of fibers in said thermoplastic wherein said random orientation of fibers is maintained during expansion by the activation of said coupling agent.