Method for production of heat-resistant container

Patent metadata

Field	Value
Publication number	US-9358739-B2
Application number	US-201113806027-A
Country	US
Kind code	B2
Filing date	Jun 16, 2011
Priority date	Jun 28, 2010
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

An invention of a method for production of a heat-resistant container, in which a raised bottom portion is displaced inwardly by reduction in internal pressure, is disclosed. The method is characterized by forming a raised bottom portion 11 smaller in wall thickness than a surrounding wall portion 12 a by first blow molding using a heat-treating blow mold; and pushing up the raised bottom portion 11 by a secondary bottom mold, in performing second blow molding using a final blow mold, to increase the wall thickness of the surrounding wall portion 12 a (ground portion 12 ) relative to the raised bottom portion.

First claim

What is claimed is:

1. A method for production of a heat-resistant container, comprising:
forming a raised bottom portion, which is displaced inwardly a predetermined amount and which is smaller in wall thickness than a surrounding section, in a bottom section of a molded product; and
performing blow molding to form a folded-back portion and a surrounding wall portion which surround the raised bottom portion,
wherein when the blow molding is performed, a site of the bottom section is pressed from outside, whereby the folded-back portion and the surrounding wall portion are formed, with the surrounding wall portion being inhibited from thinning, so that the raised bottom portion will be further displaced inwardly beyond the predetermined amount in response to reduction of internal pressure.

2. The method for production of a heat-resistant container according to claim 1 , further comprising:
forming the raised bottom portion smaller in wall thickness than the surrounding wall portion by first blow molding involving heat treatment; and
pressing the site of the bottom section including the folded-back portion and the surrounding wall portion, in performing second blow molding using a final mold, to inhibit the surrounding wall portion from thinning.

3. The method for production of a heat-resistant container according to claim 2 , wherein
a ratio between a first wall thickness (t1) of the raised bottom portion and a second wall thickness (t2) of the surrounding wall portion is 0.85 or less (t1/t2≦0.85).

4. The method for production of a heat-resistant container according to claim 3 , wherein
as a heating temperature for the bottom section, a temperature in the second blow molding is equal to or higher than a temperature in the first blow molding.

5. The method for production of a heat-resistant container according to claim 4 , wherein
the second blow molding is performed to shape the raised bottom portion into an inclined portion which extends from the surrounding wall portion diametrically inwardly in succession to the folded-back portion and inclines outwardly, and a central portion which is disposed in a center of the raised bottom portion in succession to the inclined portion and is concave inwardly, and
an angle between the surrounding wall portion and the inclined portion in a cross-sectional shape of the raised bottom portion is set at 90 degrees±15 degrees.

Assignees

• Tsuchiya Yoichi
• Nissei Asb Machine Co Ltd

Inventors

• Tsuchiya Yoichi

Classifications

• B29C49/18

  using several blowing steps (B29C49/16 takes precedence) · CPC title

• B29D22/003 Primary

  Containers for packaging, storing or transporting, e.g. bottles, jars, cans, barrels, tanks · CPC title

• B29C49/185

  Operations & Transport · mapped topic

• B65D1/0261 Primary

  Bottom construction (B65D1/06 takes precedence) · CPC title

• B29C49/541

  having a recessed undersurface · CPC title