Polypropylene resin hollow molded foam article and a process for the production thereof

Abstract

The present invention relates to a hollow molded foam article in which a plurality of polypropylene resins are used as the base resin, and to a process for the production of this hollow molded foam article. More particularly, the present invention relates to a polypropylene resin hollow molded foam article having a foam layer, in which the base resin comprises (a) a polypropylene resin with a melt tension of at least 98 mN and a melt flow rate of 0.5 to 15 g/10 minutes, (b) a polypropylene resin with a melt tension of less than 30 mN (excluding O) and a melt flow rate of 2 to 30 g/10 minutes, and (c) a polypropylene resin with a melt tension of at least 30 mN and less than 98 mN and a melt flow rate of 2 to 15 g/10 minutes, formed by positioning in a mold a softened cylindrical foam having a foam layer obtained by extruding from the die of an extruder a foamable molten resin composition containing a foaming agent, wherein the melt tension at 230° C. of the polypropylene resin that forms the foam layer is at least 10 mN and less than 49 mN, and the apparent density of the foam layer is no more than 0.3 g/cm 3 .

1 . A polypropylene resin hollow molded foam article comprising a polypropylene resin foam layer, formed by placing a softened cylindrical foam in a metal mold, wherein the melt tension at 230° C. of the polypropylene resin that forms said foam layer is at least 10 mN and less than 49 mN, and the apparent density of said foam layer is no more than 0.3 g/cm 3 .  
   
   
       2 . The polypropylene resin hollow molded foam article according to  claim 1 , having a resin layer on the outside and/or the inside of the foam layer.  
   
   
       3 . The polypropylene resin hollow molded foam article according to  claim 1 , wherein the hollow molded foam is molded by blowing a gas into the interior of a cylindrical foam.  
   
   
       4 . (canceled)  
   
   
       5 . (canceled)  
   
   
       6 . (canceled)  
   
   
       7 . (canceled)  
   
   
       8 . The polypropylene resin hollow molded foam article according to  claim 2 , wherein the hollow molded foam is molded by blowing a gas into the interior of a cylindrical foam.