Double-Layered Container Air Gap Formation via Split Mold Pinching
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Solution Overview
Problem
Existing double-layered containers face challenges in forming an opening to allow external air to enter between the rigid outer and flexible inner layers without complex processing or damage, making them unsuitable for mass production.
Innovation Solution
A method using a split mold to form a double-layered container with a threaded cap and one-way valve, allowing the flexible inner layer to reduce capacity while maintaining the rigid outer layer's profile, and creating a gap for air introduction through a simple screwing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible inner container part is held in contact with the inner surface of the rigid outer container part, then the container maintains structural integrity, but external air cannot enter the space between the layers to correspond with consumed content volume
Solution Approach 1:
The patent forms a protrusion on the inner surface of the rigid outer container part before filling, which preliminarily creates the structural feature needed for later air entry. This protrusion serves as a predetermined separation point that will allow the flexible inner layer to detach and air to enter as content is consumed.
Solution Approach 2:
The patent segments the contact interface between the rigid outer container part and flexible inner container part by forming a protrusion that creates a localized separation zone. This segmentation allows the flexible layer to remain in contact for structural support while providing a specific region where air can eventually enter.
2Ease of operation
If a opening is formed to allow external air to enter between the rigid outer container part and flexible inner container part, then air can correspond with consumed content volume, but the opening formation process becomes complex and damages the container
Solution Approach 1:
The opening formation is performed preliminarily during the molding process itself, rather than as a separate post-processing step. The protrusion is formed on the rigid outer container part before filling, and the flexible inner layer is positioned to contact this protrusion, so that the opening structure is already in place and simply needs to be activated by layer separation.
Solution Approach 2:
The container structure itself provides the air entry mechanism through its own geometric features (the protrusion and the flexible layer's ability to detach), without requiring external devices or complex processing. The flexible inner layer's natural movement as content is consumed automatically activates the air entry function.
3Reliability
If the flexible inner container part reduces capacity as content is consumed, then oxidation is prevented, but the rigid outer container part cannot maintain its profile while allowing layer separation
Solution Approach 1:
The patent applies local quality by creating a localized protrusion feature on the inner surface of the rigid outer container part, rather than changing the entire container structure. This localized feature allows the flexible inner layer to detach and air to enter in a specific region, while the rest of the rigid outer container part maintains its overall profile and structural integrity.
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
Enables easy and reliable formation of an opening for external air entry, reducing production costs and ensuring the container's functionality, while maintaining the rigid outer layer's profile and separating the inner and outer layers without damage.
Implementation Method 1
the shield member has a one way valve that allows external air to enter the gap
Implementation Method 2
forming a gap burr by pinching the parts of the parison corresponding to the small diameter part between at least parts of the joining faces of the pair of partial molds when the pair of partial molds are brought close to each other
Implementation Method 3
screwing the cap on and applying tension to the small diameter part cleared of the gap burr in the direction for separating the threaded part of the mouth section engaged with the threaded cap and the large diameter part to produce a gap
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
Provided is a method for producing a double-layered container which can be easily produced using molding equipment that is not much different from conventionally used equipment and which comprises: a rigid outer layer container part; and a flexible inner layer container part of which the capacity can be changed inside the rigid outer layer container part, wherein, when a pair of partial molds are brought close to each other in order to be combined to form a split mold, at least parts of the joining faces of the pair of partial molds pinch a small outer diameter portion of a parison so as to form a gap burr, and, when a cap is screwed on, a gap for introducing external air in the interlayer of the double-layered container is formed at the small outer diameter portion from which the gap burr has been removed.