Mold, blow molded product, and molding method

Abstract

In order to provide a mold of a shape which has been designed to take into account the deformation occurring during the cooling process, the mold cavity is formed so that the external volume of a molded product obtained by blow molding in this cavity ultimately shrinks by a prescribed percentage of the volume of the mold cavity, and so that in the region of maximum shrinkage the external size of the body portion of the molded product shrinks by a prescribed percentage of the size of the corresponding portion of the mold cavity.

What is claimed is:  
     
         1 . A mold for blow molding a thermoplastic product, comprising a mold cavity sized such that the external volume of a molded product blow molded in the cavity has a desired shape and size after the external volume of the molded product has shrunk by between 5.8% and 13.5% of the volume of the cavity.  
     
     
         2 . A mold according to  claim 1 , wherein the thermoplastic is high-density polyethylene (HDPE), and the mold cavity is sized and shaped in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 7.0% and 13.5% of the volume of the cavity.  
     
     
         3 . A mold according to  claim 1 , wherein the thermoplastic is polypropylene (PP), and the mold cavity is sized and shaped in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 5.8% and 8.5% of the volume of the cavity.  
     
     
         4 . A mold for blow molding a thermoplastic product, wherein the mold cavity is sized and shaped in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 5.8% and 13.5% of the volume of the cavity, and in view of the shrinkage of a region of maximum shrinkage of the external size of the body portion of the molded product being between 1.0% and 10.5% of the size of the corresponding portion of the mold cavity.  
     
     
         5 . A mold according to  claim 4 , wherein the thermoplastic is HDPE, wherein the mold cavity is sized and shaped in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 7.0% and 13.5% of the volume of the cavity, and in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 1.5% and 10.5% of the size of the corresponding portion of the mold cavity.  
     
     
         6 . A mold according to  claim 4 , wherein the mold cavity is sized and shaped in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 5.8% and 8.5% of the volume of the cavity, and in view of the external volume of the molded product obtained by blow molding in the cavity shrinking by between 1.0% and 10.5% of the size of the corresponding portion of the mold cavity.  
     
     
         7 . A method for blow molding a thermoplastic product, comprising the steps of: 
 providing a mold cavity sized such that the external volume of a molded product blow molded in the cavity has a desired shape and size after the external volume of the molded product has shrunk by between 5.8% and 13.5% of the volume of the cavity;    blow molding a thermoplastic product in the mold cavity; and    permitting the external volume of the thermoplastic product to shrink by between 5.8% and 13.5% of the volume of the cavity.    
     
     
         8 . A method according to  claim 7 , wherein the thermoplastic is high-density polyethylene (HDPE) and the molded product shrinks by between 7.0% and 13.5% of the volume of the cavity.  
     
     
         9 . A method according to  claim 7 , wherein the thermoplastic is polypropylene (PP) and the external volume of the molded product shrinks by 5.8% and 8.5% of the volume of the cavity.  
     
     
         10 . A blow molded product on the body portion of which an in-mold label has been affixed using a mold comprising a mold cavity sized such that the external volume of a molded product blow molded in the cavity has a desired shape and size after the external volume of the molded product has shrunk by between 5.8% and 13.5% of the volume of the cavity, said in-mold label excluding labels which do not thermally shrink after removal from a mold.