Container with synthetic resin window, preform, and preform injection molding apparatus

Patent metadata

Field	Value
Publication number	US-10086551-B2
Application number	US-201715675129-A
Country	US
Kind code	B2
Filing date	Aug 11, 2017
Priority date	Nov 30, 2012
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

To solve a problem associated with formation of a transparent window portion in a biaxially stretch blow molded container by a nozzle structure of an injection molding apparatus, provided is a biaxially stretch blow molded container formed with a clearly transparent window portion in longitudinal strip shape by effectively preventing mixture of colored resin to window portion. Injection molding apparatus includes in nozzle portion a longitudinal groove flow path, wherein a transparent B resin flows. By, for example, reducing and increasing, respectively, the width and depth of the longitudinal groove flow path on the downstream side, and engraving slits in an inner mandrel and even in a front end portion of a stopper pin, flowability of the B resin in a horizontal direction is enhanced.

First claim

The invention claimed is:

1. An injection molding apparatus that injection molds a test-tube-shaped preform that is subjected to biaxial stretch blow molding, the preform including a circumferential wall having a longitudinal strip-shaped portion that is made of a B resin and that is formed in a longitudinal strip shape in a circumferentially predetermined position in the circumferential wall over a predetermined height range, a remaining portion of the circumferential wall excluding the longitudinal strip-shaped portion being made of an A resin, the injection molding apparatus comprising:
a nozzle portion that supplies the A resin and the B resin which are molten along a circumferential direction; and
a mold that is located in a front end of the nozzle portion, wherein
the nozzle portion includes:
a cylindrical inner mandrel; an outer mandrel that is arranged coaxially with the inner mandrel; and a columnar shut-off pin that is inserted and arranged in the inner mandrel and that serves to release and shut off flows of the molten resins in a front end portion of the nozzle portion, and wherein
between the inner mandrel and the outer mandrel, a cylindrical flow path and a reduced-diameter flow path are formed in the stated order in a direction toward a downstream side, the reduced-diameter flow path being configured by a cylindrical flow path tapered to have a reduced diameter toward downstream, and on downstream of the reduced-diameter flow path, a columnar joining flow path is formed in which the molten resins in cylindrical forms join into a columnar form, and a longitudinal groove flow path is further formed to interrupt the cylindrical flow path and the reduced-diameter flow path in a circumferential direction,
the longitudinal groove flow path has a flow path width that is reduced on a downstream side below a predetermined position than on an upper stream side thereof and a flow path depth that is increased on the downstream side below the predetermined position than on the upper stream side thereof,
the molten B resin is supplied to the longitudinal groove flow path, and the molten A resin is supplied to the cylindrical flow path excluding the longitudinal groove flow path and the molten resins that have joined into the columnar form are injected and filled into a cavity of the mold via the joining flow path of the nozzle portion and a pin gate located in a position of the cavity of the mold that corresponds to a middle of a bottom wall of a bottom portion of the preform.

2. The injection molding apparatus of claim 1 , wherein, in the cylindrical flow path and the reduced-diameter flow path, a pair of guiding ribs in the form of longitudinal ridges is arranged in line to partition the cylindrical flow path and the reduced-diameter flow path in the circumferential direction, and the longitudinal groove flow path is formed between the pair of guiding ribs.

3. The injection molding apparatus of claim 1 , wherein the longitudinal groove flow path has a flow path width that is reduced from a position of a lower end portion of the cylindrical flow path.

4. The injection molding apparatus of claim 1 , wherein the inner mandrel forming the reduced-diameter flow path is engraved with a slit having an inclination angle that is greater than an inclination angle that the tapered reduced-diameter flow path forms with respect to a central axis of the nozzle portion, in order to increase a flow path depth of the longitudinal groove flow path.

5. The injection molding apparatus of claim 4 , wherein, in a release position of the shut-off pin, the slit engraved in the inner mandrel is further extended into the shut-off pin to engrave a slit in a portion of the shut-off pin that is located from a circumferential wall to a front end surface thereof, the slit having the inclination angle.

6. The injection molding apparatus of claim 5 , wherein, in the front end surface of the shut-off pin, the slit is engraved from a peripheral edge toward a center and beyond a center position of the front end surface.

Assignees

• Yoshino Kogyosho Co Ltd

Inventors

• Soyama Hideaki
• Ishii Yusuke

Classifications

• B29B11/14 Primary

  characterised by structure or composition · CPC title

• B29C49/06 Primary

  Injection blow-moulding · CPC title

• B29C2949/3006

  having tangentially different components within one layer, e.g. longitudinal stripes · CPC title

• B65D25/54

  Inspection openings or windows · CPC title

• B65D1/40

  Details of walls (other container details B65D23/00, B65D25/00) · CPC title