초록 ▼

Spherulites are grown in such sections as neck, neck end, bottom center and/or bottom periphery of a hollow bottle-shaped container of biaxially oriented-blow molded polyethylene terephthalate (PET) resin where the resin is not substantially subjected to orientation, thereby to improve the thermal r

Spherulites are grown in such sections as neck, neck end, bottom center and/or bottom periphery of a hollow bottle-shaped container of biaxially oriented-blow molded polyethylene terephthalate (PET) resin where the resin is not substantially subjected to orientation, thereby to improve the thermal resistance, stiffness and content resistance of such sections to almost the same extent as the biaxially oriented sections of the container such as the shoulder and cylindrical sections thereof. The aforesaid non-oriented sections of the preformed piece before being blow-molded or of the blow-molded container are first heated at or above the glass transition temperature of the resin for about 2-8 minutes and are then annealed at room temperature, with the result that such sections have a spherulite texture of an increased density and are rendered opaque.

대표청구항 ▼

A method for producing a hollow bottle-shaped container of biaxially oriented polyethylene terephthalate having a non-biaxially oriented neck section, a bottom section, and a biaxially oriented body section extending between said neck section and bottom section from a preform having a prefinished ne

A method for producing a hollow bottle-shaped container of biaxially oriented polyethylene terephthalate having a non-biaxially oriented neck section, a bottom section, and a biaxially oriented body section extending between said neck section and bottom section from a preform having a prefinished neck section, said method comprising the steps of: biaxially orienting in a mold only the regions of the preform below said neck section, including those immediately therebelow, to form the hollow bottle-shaped container, heating only the prefinished neck section of said container to a heating temperature of at least the glass transition temperature of the polyethylene terephthalate for a heating time at least long enough to begin formation of crystal nuclei, and thereafter cooling the neck section to increase the density of the spherulite texture only in the neck section to produce a container having a crystallized area only in the neck section.