Double-Layer Polyester Container Shoulder Rib for Stable Air Passage

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Solution Overview

Problem

Conventional double containers face difficulties in securing a smooth air passage from the outside air introduction port to the barrel portion, especially when the inner layer body is made of polyester resin such as polyethylene terephthalate.

Innovation Solution

A double container design featuring a tubular mouth portion with an outside air introduction port and a shoulder rib that is concave or convex, extending from the shoulder portion, along with a structured inner layer body projection pieces to maintain an air passage between the outer and inner layers, ensuring easy air passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner layer body is made of polyester resin to achieve good barrier properties and chemical resistance, then the container exhibits improved durability and content protection, but the air passage from the outside air introduction port to the barrel portion becomes difficult to secure

Engineering Contradiction:
Improvecontent protectionVSAvoidair passage
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The inner layer body is segmented into multiple functional zones: a mouth portion with a smaller inner diameter than the outer layer body, a barrel portion, and projection pieces extending upward. This segmentation creates dedicated air passage channels between the layers while maintaining the barrier properties of polyester resin throughout the structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air passage is established not only radially between the outer and inner layers but also axially through the projection pieces that extend upward from the inner layer body. This multi-dimensional air channel configuration ensures smooth air flow from the outside air introduction port to the barrel portion while maintaining the integrity of the polyester resin inner layer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the mouth portion has a large diameter to facilitate filling and discharge operations, then the ease of operation is improved, but the air passage space between the outer and inner layers is reduced

Engineering Contradiction:
Improvefilling and dischargeVSAvoidair passage space
Core Design Contradiction:
Ease of operationVSVolume of stationary object

Solution Approach 1:

The inner layer body's mouth portion is designed with a smaller inner diameter than the outer layer body's mouth portion, creating an annular air passage space. This segmentation allows the outer mouth to remain large for easy filling and discharge while the inner mouth creates a dedicated channel for air flow between the layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air passage utilizes both the radial dimension (annular space between outer and inner layer mouth portions) and the axial dimension (projection pieces extending upward from the inner layer). This multi-dimensional approach maintains adequate air passage volume even when the overall mouth diameter is large.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3919398B1Double-layered container
Publication Date: 2026.02.18 YOSHINO KOGYOSHO CO LTD
  • EP3919398B1 patent drawingFigure 1
  • EP3919398B1 patent drawingFigure 2
  • EP3919398B1 patent drawingFigure 3

AI summary

A double container (1) has an outer layer body (2) and an inner layer body (3) mainly made of a polyester resin and is formed by biaxial stretch blow molding, and comprises: a mouth portion (4); a shoulder portion (5), gradually increasing in diameter in a downward direction, and having an outward protruding curved shape over a length in a vertical direction in a longitudinal section; a barrel portion (6) ; and a bottom portion (7) , wherein the mouth portion (4) has an outside air introduction port (13) for introducing outside air between the outer layer body (2) and the inner layer body (3), and the double container comprises a shoulder rib (8) that is concave or convex as seen from outside and at least extends from an upper end of the shoulder portion (5) to the lower end of the shoulder portion (5).