US-12623395-B2 - Preform for forming double container

US12623395B2US 12623395 B2US12623395 B2US 12623395B2US-12623395-B2

Abstract

A preform for forming a double container configured to form a double container including an inner container and an outer container. The preform includes a bottomed cylindrical inner preform configured to form the inner container and a bottomed cylindrical outer preform configured to form the outer container. The inner preform is inserted into the outer preform, a longitudinal groove is formed in an inner peripheral surface of a mouth portion of the outer preform, an outside air introduction hole opens in a longitudinal groove, and a flange portion is provided in a mouth portion of the inner preform.

Inventors

Tomoaki Kurihara
Toshimasa Tanaka
Takanori Suzuki

Assignees

YOSHINO KOGYOSHO CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20220426
Priority Date: 20210426

Claims (4)

1 . A preform for forming a double container, the preform configured to form a double container including: an inner container configured to be deformed to reduce a capacity according to reduction in contents accommodated; and an outer container in which the inner container is installed, and which is provided with an outside air introduction hole into which an outside air is introduced between the inner container and the outer container according to reduction in the contents, the preform comprising: a bottomed cylindrical inner preform configured to form the inner container; and a bottomed cylindrical outer preform configured to form the outer container, wherein the inner preform is inserted into the outer preform in a state in which a mouth portion of the inner preform is fitted into a mouth portion of the outer preform, a longitudinal groove, extending downward from an upper end opening edge of the outer preform, is formed in an inner peripheral surface of the mouth portion of the outer preform, the outside air introduction hole opens in the longitudinal groove, a flange portion continuously extending over an entire length in a circumferential direction, abutting the upper end opening edge of the outer preform over the entire length in a circumferential direction, and closing an upper end opening of the longitudinal groove, is provided on the mouth portion of the inner preform, and the outside air introduction hole is disposed below and apart from the upper end opening edge of the outer preform.
2 . The preform for forming a double container according to claim 1 , wherein when seen in a longitudinal cross-sectional view along a central axis of the inner preform, an inner peripheral surface and an outer peripheral surface of the mouth portion of the inner preform extend along the central axis.
3 . The preform for forming a double container according to claim 1 , wherein a projection portion protruding outward in a radial direction, continuously extending over the entire length in the circumferential direction, and pressed against the inner peripheral surface of the mouth portion of the outer preform, is provided in an outer peripheral surface of the mouth portion of the inner preform.
4 . The preform for forming a double container according to claim 1 , wherein a diffusion gap continuously extending over the entire length in the circumferential direction, is provided between a connecting portion to a lower surface of the flange portion in an outer peripheral surface of the inner preform and a connecting portion to the inner peripheral surface and the upper end opening edge of the outer preform.

Description

TECHNICAL FIELD The present invention relates to a preform for forming a double container. Priority is claimed on Japanese Patent Application No. 2021-073768, filed Apr. 26, 2021, the content of which is incorporated herein by reference. BACKGROUND ART A preform configured to form a double container including: an inner container configured to be deformed to reduce a capacity thereof according to reduction in contents accommodated; and an outer container in which an inner container is installed, and which is provided with an outside air introduction hole through which an outside air is introduced between the inner container and the outer container according to reduction in contents, includes: a bottomed cylindrical inner preform configured to form the inner container; and a bottomed cylindrical outer preform configured to form the outer container. As such a preform for forming a double container, for example, as disclosed in the following Patent Document 1, a configuration in which an inner preform is fitted into an outer preform and a peeling agent layer is provided between an inner peripheral surface of the outer preform and an outer peripheral surface of the inner preform is known. In the double container formed by the preform, when outside air is introduced between the inner container and the outer container through the outside air introduction hole according to reduction in contents, an outer peripheral surface of the inner container can be easily peeled off from an inner peripheral surface of the outer container. CITATION LIST Patent Document [Patent Document 1]Japanese Unexamined Patent Application, First Publication No. 2010-82916 SUMMARY OF INVENTION Technical Problem However, in the preform for forming a double container in the related art, since a peeling agent layer is provided between the inner peripheral surface of the outer preform and the outer peripheral surface of the inner preform, there is a problem that manufacturing is difficult. In consideration of the above-mentioned circumstances, the present invention is directed to providing a preform for forming a double container in which an outer peripheral surface of an inner container is able to be easily peeled from an inner peripheral surface of an outer container according to reduction in contents even when a peeling agent layer is not provided. Solution to Problem The present invention employs the following means in order to solve the above-mentioned problems. That is, a first aspect of the present invention is a preform for forming a double container, the double container configured to form a double container including: an inner container configured to be deformed to reduce a capacity according to reduction in contacts accommodated; and an outer container in which the inner container is installed, and provided with an outside air introduction hole into which outside air is introduced between the inner container and the outer container according to reduction in the contents. The preform for forming a double container includes: a bottomed cylindrical inner preform configured to form the inner container, and a bottomed cylindrical outer preform configured to form the outer container. The inner preform is inserted into the outer preform in a state in which a mouth portion of the inner preform is fitted into a mouth portion of the outer preform. A longitudinal groove extending downward from an upper end opening edge of the outer preform is formed in an inner peripheral surface of the mouth portion of the outer preform. The outside air introduction hole opens in the longitudinal groove. A flange portion continuously extending over an entire length in a circumferential direction, abutting an upper end opening edge of the outer preform, and closing an upper end opening of the longitudinal groove is provided on the mouth portion of the inner preform. In the present invention, the longitudinal groove extending downward from the upper end opening edge of the outer preform is formed in the inner peripheral surface of the mouth portion of the outer preform, and the outside air introduction hole opens in the longitudinal groove. Accordingly, even in a state in which the mouth portion of the inner preform is fitted into the mouth portion of the outer preform and relative movement between the outer preform and the inner preform is curbed, outside air passes through the longitudinal groove when the outside air is introduced between the inner container and the outer container through the outside air introduction hole. Accordingly, even when a peeling agent layer is not provided, the outer peripheral surface of the inner container can be peeled off from the inner peripheral surface of the outer container according to reduction in contents. The longitudinal groove extends downward from the upper end opening edge of the outer preform. Accordingly, the longitudinal groove can be easily provided in the inner peripheral surface of the outer preform without compl