(EP880556-A1)      A quick extrusion foaming process for producing a closed cell propylene resin foam comprises;    (A) feeding a propylene resin into an extruder;    (B) adding a nucleating agent to the resin feed;    (C) plasticating the mixture forming a melt;    (D) adding an organic blowing agent and/or an inorganic blowing agent to form a foamable composition;    (E) uniformly mixing and cooling the composition to a temperature effective for the expansion of the foam; and    (F) extruding or ejecting the mix through a die at a rate high enough to form a low density closed-cell foam with a Foamability Index greater than 1.9 and an Ebullition Time less than 2.0x10-4 seconds.    Also claimed is the low density closed-cell propylene resin foam.    USE -   The process is useful for the production of foamed thermoplastic material as an energy absorbing material for high speed impact protection and in acoustical and energy absorbing structures.    ADVANTAGE -   The process is simple, low cost and reliable and does not use stratospheric ozone harming compounds. The resulting foam has improved mechanical and heat resistance properties.    (US5817705-A)      A quick extrusion foaming process for producing a closed cell propylene resin foam comprises;    (A) feeding a propylene resin into an extruder;    (B) adding a nucleating agent to the resin feed;    (C) plasticating the mixture forming a melt;    (D) adding an organic blowing agent and/or an inorganic blowing agent to form a foamable composition;    (E) uniformly mixing and cooling the composition to a temperature effective for the expansion of the foam; and    (F) extruding or ejecting the mix through a die at a rate high enough to form a low density closed-cell foam with a Foamability Index greater than 1.9 and an Ebullition Time less than 2.0x10-4 seconds.    Also claimed is the low density closed-cell propylene resin foam.    USE -   The process is useful for the production of foamed thermoplastic material as an energy absorbing material for high speed impact protection and in acoustical and energy absorbing structures.    ADVANTAGE -   The process is simple, low cost and reliable and does not use stratospheric ozone harming compounds. The resulting foam has improved mechanical and heat resistance properties.    (JP2000502402-W)      A quick extrusion foaming process for producing a closed cell propylene resin foam comprises;    (A) feeding a propylene resin into an extruder;    (B) adding a nucleating agent to the resin feed;    (C) plasticating the mixture forming a melt;    (D) adding an organic blowing agent and/or an inorganic blowing agent to form a foamable composition;    (E) uniformly mixing and cooling the composition to a temperature effective for the expansion of the foam; and    (F) extruding or ejecting the mix through a die at a rate high enough to form a low density closed-cell foam with a Foamability Index greater than 1.9 and an Ebullition Time less than 2.0x10-4 seconds.    Also claimed is the low density closed-cell propylene resin foam.    USE -   The process is useful for the production of foamed thermoplastic material as an energy absorbing material for high speed impact protection and in acoustical and energy absorbing structures.    ADVANTAGE -   The process is simple, low cost and reliable and does not use stratospheric ozone harming compounds. The resulting foam has improved mechanical and heat resistance properties.