Injection Stretch Blow Molded Container Comprising A Polyolefin Composition

Abstract

The present invention relates to an injection-stretch blow molding process (ISBM) for the manufacture of an impact-resistant container with good optical properties from a polyolefin composition comprising a polypropylene and a polyethylene produced with a metallocene-based catalyst.

1 - 12 . (canceled) 
     
     
         13 . An injection-stretch blow molded container comprising:
 a polyolefin composition comprising a polypropylene and a metallocene polyethylene;   wherein the polypropylene is a homopolymer or a random copolymer of propylene and a comonomer selected from a group consisting of ethylene and C 4 -C 10  alpha-olefins; and   wherein the metallocene polyethylene has a melt index in ranging from 5 to 30 dg/min and a density of at least 0.925 g/cm 3 .   
     
     
         14 . The container of  claim 13 , wherein there is no phase separation exhibited between the polypropylene and the metallocene polyethylene. 
     
     
         15 . The container of  claim 13 , wherein the metallocene polyethylene has a percentage of crystallization corresponding to chains having less than 10 Short Chain Branches (SCB) of at least 4%. 
     
     
         16 . The container of  claim 13 , wherein the metallocene polyethylene has a percentage of crystallization corresponding to chains having less than 10 Short Chain Branches (SCB) of at least 7%. 
     
     
         17 . The container of  claim 13 , wherein the polyolefin composition comprises from 1 wt % to 20 wt % of the metallocene polyethylene. 
     
     
         18 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at least 0.927 g/cm 3 . 
     
     
         19 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at least 0.930 g/cm 3 . 
     
     
         20 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at least 0.932 g/cm 3 . 
     
     
         21 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at most 0.945 g/cm 3 . 
     
     
         22 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at most 0.950 g/cm 3 . 
     
     
         23 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at most 0.955 g/cm 3 . 
     
     
         24 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at most 0.960 g/cm 3 . 
     
     
         25 . The container of  claim 13 , wherein the metallocene polyethylene has a density of at most 0.965 g/cm 3 . 
     
     
         26 . The container of  claim 13 , wherein the metallocene polyethylene has a molecular weight distribution ranging from 2 to 7. 
     
     
         27 . The container of  claim 13 , wherein the container is a bottle. 
     
     
         28 . The container of  claim 13 , wherein the container is prepared by a process comprising:
 providing the polyolefin composition;   preparing a preform from the polyolefin composition by injection molding at an injection temperature of at least 230° C.;   optionally cooling the preform to room temperature;   optionally re-heating the preform to a temperature ranging from 90° C. to 140° C.;   stretching the preform axially by a center rod; and   blowing the preform radially with a gas under pressure.   
     
     
         29 . The container of  claim 28 , wherein a ratio of mold filing rate (in cm 3 /s) over gate size (in mm) is 15 or less. 
     
     
         30 . The container of  claim 28 , wherein a center rod speed ranges from 100 mm/s to 2000 mm/s. 
     
     
         31 . The container of  claim 28 , wherein stretching the preform axially by the center rod comprises pre-blowing the preform with gas at a pressure ranging from 2 bars to 10 bars, and wherein blowing the preform radially with the gas under pressure is performed at a pressure ranging from 5 to 40 bars. 
     
     
         32 . The container of  claim 28 , wherein the injection temperature is at least 270° C.