Multi-layered preform and multi-layered bottle manufactured by using the same

Abstract

A multi-layered preform for substantially preventing the generation of strains and obtaining improved stress cracking resistance with excellent appearance characteristics includes a mouth portion, a body portion and a bottom portion and has at least the body portion and the bottom portion formed of an inner layer, an intermediate layer, and an outer layer by a compression molding. A multi-layered bottle is manufactured by performing a biaxial stretch blow molding of such multi-layered perform. The multi-layered bottle includes a mouth portion, a shoulder portion, a body portion and a bottom portion. At least the shoulder portion, the body portion and the bottom portion include an inner layer, an intermediate layer and an outer layer.

What is claimed is:  
     
         1 . A multi-layered preform comprising a mouth portion, a body portion and a bottom portion and having at least the body portion and the bottom portion formed of an inner layer, an intermediate layer, and an outer layer by a compression molding, wherein, at the center of the bottom portion, a half-width of a diffuse scattering peak by an X-ray diffraction of a surface of the outer layer is larger than a half-width of a diffuse scattering peak by an X-ray diffraction of a surface of the inner layer.  
     
     
         2 . A multi-layered preform according to  claim 1 , wherein one or a plurality of intermediate layers which are made of at least one kind selected from a group consisting of gas barrier resin, recycled resin and heat-resistant resin are completely sealed by the inner layer and the outer layer which are made of polyester.  
     
     
         3 . A multi-layered preform according to  claim 1  or  2 , wherein an adhesive resin layer is interposed at least either between the inner layer and the intermediate layer or between the outer layer and the intermediate layer.  
     
     
         4 . A multi-layered preform according to any one of preceding  claims 1  to  3 , wherein a gate portion or a trace of the gate portion is not present in the bottom portion.  
     
     
         5 . A multi-layered bottle which is manufactured by performing a biaxial stretch blow molding of the multi-layered preform according to any one of preceding  claims 1  to  4 , wherein the multi-layered bottle includes a mouth portion, a shoulder portion, a body portion and a bottom portion, at least the shoulder portion, the body portion and the bottom portion include an inner layer, an intermediate layer and an outer layer, and, at the center of the bottom portion, a half-width of a diffuse scattering peak by an X-ray diffraction of a surface of the outer layer is larger than a half-width of a diffuse scattering peak by an X-ray diffraction of a surface of the inner layer.