US 4,590,021 AGranted

Method for producing polyester containers

AssigneeYoshino Kogyosho Co., Ltd.

InventorsAkiho Ota, Fumio Negishi

Life of this patent

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Abstract

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.

Claims13

Dependent claims

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:

heating only the prefinished neck section of said preform to a heating temperature of at least the glass transition temperature of the preform 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 spherulitic texture only in the neck section to produce a preform having a crystallized area only in the neck section and the remainder of the preform being uncrystallized, and thereafter
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 with a crystallized area only in the neck section.

Dependencies are inferred from the claim text.

Facts

Application: 06/570,030Filed 11 Jan 1984 · continuation in part
Priority: JP 53-8984029 Jun 1978
Granted: 20 May 1986
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

B29C 71/02
After-treatment of articles without altering their shape; Apparatus therefor: thermal after-treatment
B29C 49/64
Component parts, details or accessories; Auxiliary operations: heating or cooling preforms, parisons or blown articles
B29C 49/6409
Heating or cooling preforms, parisons or blown articles: thermal conditioning of preforms
B29C 49/6452
Through the preform length: by heating the neck

Family

Serial19,913Parent of this division · filed 12 Mar 1979
Serial150,662Parent of this continuation · filed 16 May 1980
Serial317,887Parent of this continuation · filed 3 Nov 1981
Serial428,639Parent of this continuation-in-part · filed 30 Sep 1982
US 4,379,099 AParent of this continuation
US 4,590,021 AThis patent

From the US filing history. Foreign family members aren’t listed.