Synthetic Resin Container Air Passage With Crystallized Inner Regions

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Solution Overview

Problem

Delamination containers face issues with the unstretched part of the inner body near the outside air introduction hole expanding radially outward during blow molding, blocking the air passage from the outside air introduction hole to the space between the outer and inner layer bodies.

Innovation Solution

A preform and container design featuring a crystalline resin inner body with a crystallized region of higher crystallinity, incorporating air passage ribs and vertical ribs to secure an air passage, and a manufacturing method involving slow cooling to enhance rigidity and prevent radial expansion during stretch blow molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inner body is made of crystalline resin without a crystallized region, then the manufacturing process is simpler, but the unstretched part expands radially outward during blow molding and blocks the air passage

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidair passage functionality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by creating a crystallized region with higher degree of crystallinity in specific areas of the inner body (mouth portion and lower part of barrel portion) while keeping other regions with normal crystallinity. This localized structural modification prevents radial expansion in critical areas during blow molding, ensuring air passage functionality without requiring complete structural redesign of the entire inner body.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements preliminary action by forming the crystallized region with higher rigidity before the blow molding process. This pre-established rigid structure in the unstretched parts prevents radial expansion during the subsequent blow molding and air introduction operations, ensuring the air passage remains open without requiring complex real-time control during manufacturing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the inner body is made more rigid to prevent radial expansion, then the air passage remains open, but the manufacturing complexity increases due to required crystallized regions

Engineering Contradiction:
Improveair passage opennessVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Rather than making the entire inner body complex or uniformly rigid, the patent applies local quality by creating crystallized regions only in specific areas where radial expansion would block the air passage (mouth portion and lower barrel portion). This targeted approach maintains structural simplicity while ensuring air passage functionality.

Inventive Principle:
Principle #3Local quality

3Strength

If the entire inner body is made with high rigidity, then radial expansion is prevented, but the manufacturing process becomes more complex and costly

Engineering Contradiction:
Improveinner body rigidityVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent resolves this contradiction by applying local quality - creating crystallized regions with high rigidity only in specific areas (mouth portion and lower barrel portion) where it is most needed to prevent air passage blockage. The rest of the inner body maintains normal crystallinity and flexibility, simplifying the overall manufacturing process compared to making the entire structure rigid.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by controlling the degree of crystallinity in different regions of the inner body. By adjusting the crystallization parameters (temperature, time, cooling rate) during manufacturing, the patent creates localized regions of higher crystallinity and rigidity without requiring complete structural redesign or complex multi-step manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design ensures easy and uninterrupted air passage from the outside air introduction hole to the barrel portion, maintaining container functionality and reducing content exposure to air, thereby minimizing degradation.

Implementation Method 1

the inner body is made of a crystalline resin, and has, in at least a part of the mouth portion in the inner body, a crystallized region having a higher degree of crystallinity than other regions of the inner body

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Implementation Method 2

An air passage rib extending in a vertical direction is formed on an outer circumferential surface in at least a part of the crystallized region

Methodology Applied
Scientific EffectFluid flow through structured passage:

Data Source

PatentEP3733538B1Synthetic resin-made container, preform, and method of manufacturing synthetic resin-made container
Publication Date: 2025.09.10 YOSHINO KOGYOSHO CO LTD
  • EP3733538B1 patent drawingFigure 1
  • EP3733538B1 patent drawingFigure 2
  • EP3733538B1 patent drawingFigure 3A~3B

AI summary

Provided are a synthetic resin-made container, a preform, and a method of manufacturing a synthetic resin-made container that can easily secure an air passage from an outside air introduction hole to a barrel portion. A synthetic resin-made container 1 has an outer layer body 2 and an inner layer body 3 separably laminated on an inner surface of the outer layer body 2 and is formed by stretch blow molding, and comprises: a tubular mouth portion 4; a shoulder portion 7 located below the mouth portion 4 and increasing in diameter downward; a barrel portion 5 connected to and located below the shoulder portion 7; and a bottom portion 6 closing a lower end of the barrel portion 5, wherein the mouth portion 4 has an outside air introduction hole 4b for introducing outside air into a space between the outer layer body 2 and the inner layer body 3, and the inner layer body 3 is made of a crystalline resin, and has, in at least a part of the mouth portion 4 in the inner layer body 3, a crystallized region 9 having a higher degree of crystallinity than other regions.