Injection Stretch Blow Molded Polylactide Bottle and Process For Making Same

Abstract

An injection stretch blow molding process for making containers from a polylactic acid resin. In one aspect the process comprises molding the polylactic acid resin into a perform, applying heat to the perform, stretching and blowing the perform in axial and radial dimensions in order to form a preliminary molded container, conditioning the molded container pursuant to a first conditioning method, conditioning the molded container pursuant to a second conditioning method, and stretching and blowing the molded container in order to form a final molded container. Relatively rigid bottles constructed in accordance with one or more processes disclosed herein are also contemplated.

1 . An injection stretch blow molding process for making containers from a polylactic acid resin, comprising:
 molding the polylactic acid resin into a preform;   applying heat to the preform;   stretching and blowing the perform in axial and radial dimensions in order to form a preliminary molded container;   conditioning the molded container pursuant to a first conditioning method;   conditioning the molded container pursuant to a second conditioning method; and   stretching and blowing the molded container in order to form a final molded container.   
   
   
       2 . The injection stretch blow molding process of  claim 1 , wherein applying heat to the preform is performed substantially contemporaneously with molding the polylactic resin into a preform. 
   
   
       3 . The injection stretch blow molding process of  claim 1 , wherein applying heat to the preform is performed subsequent to the molding of the preform. 
   
   
       4 . The injection stretch blow molding process of  claim 3 , wherein applying heat to the preform is performed after the molded preform has cooled. 
   
   
       5 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a first conditioning method comprises raising the temperature and pressure of the molded container for a fixed period of time. 
   
   
       6 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a first conditioning method comprises direct contact heat setting. 
   
   
       7 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a first conditioning method comprises heat setting in an oven. 
   
   
       8 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a first conditioning method comprises raising the temperature of the molded container to a temperature above the glass transition temperature of the polylactic resin. 
   
   
       9 . The injection stretch blow molding process of  claim 1 , wherein the first conditioning method and the second conditioning method are the same. 
   
   
       10 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a first conditioning method comprises raising the pressure of the molded container to a predefined pressure. 
   
   
       11 . The injection stretch blow molding process of  claim 1 , wherein conditioning the molded container pursuant to a second conditioning method comprises raising the pressure of the molded container to a predefined pressure. 
   
   
       12 . The injection stretch blow molding process of  claim 1 , wherein the polylactic resin is a copolymer having repeating L and D lactic acid units in which either the L or D units are the predominant repeating units and the predominant repeating units constitute 90 to 99.5% of the lactic acid repeating units. 
   
   
       13 . The injection stretch blow molding process of  claim 1 , wherein the polylactic resin is a blend of copolymers wherein the predominant repeating units in the blend of copolymers constitute 90 to 99.5% of the lactic acid enantiomer repeating units. 
   
   
       14 . The injection stretch blow molding process of  claim 1 , wherein 92 to 99% of the lactic acid enantiomer repeating units in the polylactic resin are of the predominant lactic acid enantiomer. 
   
   
       15 . The injection stretch blow molding process of  claim 1 , wherein the polylactic resin includes at least one additive. 
   
   
       16 . The injection stretch blow molding process of  claim 15 , wherein the additive is selected from the group consisting of a colorant and a thermal stabilizer. 
   
   
       17 . A container formed from a polylactic acid-based resin through an injection stretch blow molding manufacturing process, the manufacturing process comprising:
 molding the polylactic acid resin into a preform;   applying heat to the preform;   stretching and blowing the perform in axial and radial dimensions in order to form a preliminary molded container;   conditioning the molded container pursuant to a first conditioning method;   conditioning the molded container pursuant to a second conditioning method; and   stretching and blowing the molded container in order to form a final molded container.   
   
   
       18 . The container of  claim 17 , wherein the average sidewall thickness of the container is greater than 40 mils. 
   
   
       19 . The container of  claim 17 , wherein the average sidewall thickness of the container is greater than 60 mils. 
   
   
       20 . An injection stretch blow molding process for making containers from a polylactic acid resin, comprising:
 molding the polylactic acid resin into a preform;   raising the temperature of the preform to between 60° C. and 80° C.;   stretching and blowing the perform in axial and radial dimensions in order to form a preliminary molded container;   raising the temperature of the molded container to between 60° C. and 100° C.; and   stretching and blowing the molded container in order to form a final molded container.