Multilayer Cup Container Gas Barrier Joint Formation
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Solution Overview
Problem
Existing methods for manufacturing multilayer containers with gas barrier properties face challenges in uniformly forming intermediate layers, especially when thinning walls, and integrating gas barrier films around the container trunk portion, which affects mass production stability and gas barrier performance at joint portions.
Innovation Solution
A method involving in-mold molding where a gas barrier label film is wound around the container trunk and resins are injected with a gas barrier resin fed as a strip between the surface resins at the joint portion, forming a continuous longitudinal strip-shaped gas barrier layer inside the container trunk and a plane-shaped layer at the bottom, ensuring effective gas barrier properties without requiring uniform intermediate layers throughout the container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer container is manufactured by injecting resins from one injection molding nozzle to form an intermediate layer, then gas barrier properties are improved, but it is technically difficult to form the intermediate layer uniformly in the entire container while thinning walls
Solution Approach 1:
The injection molding nozzle is divided into multiple independent resin discharge ports (first, second, and third discharge ports) that can discharge different resins separately. This segmentation allows the gas barrier resin to be discharged only at specific locations (joint portions of the label film) rather than uniformly throughout the container, solving the problem of non-uniform intermediate layer formation while maintaining gas barrier properties.
Solution Approach 2:
The gas barrier resin is discharged locally only at the joint portions of the label film through the third resin discharge port, rather than uniformly across the entire container. This local quality approach concentrates the gas barrier function where it is most needed (at the joint portions) while allowing other areas to have thinner walls, thus resolving the contradiction between gas barrier properties and wall thinning uniformity.
2Reliability
If a film having gas barrier properties is disposed on the outer surface of the container by in-mold molding, then gas barrier properties are improved, but bonded faces are necessarily required at ends of the film which makes it difficult to impart expected gas barrier properties at bonded portions
Solution Approach 1:
A gas barrier resin is introduced as an intermediary material between the label film and the container surface. This gas barrier resin fills the joint portions of the label film and forms a continuous gas barrier layer that connects the label film to the container bottom, eliminating the weakness at the bonded faces and ensuring continuous gas barrier properties throughout the container.
Solution Approach 2:
The container structure becomes a composite of multiple materials: the label film (outer layer), the gas barrier resin (intermediate layer), and the container resin (inner layer). This composite structure combines the advantages of each material, with the gas barrier resin specifically addressing the weakness at the label film joints while maintaining the overall gas barrier function.
3Reliability
If multilayer molding is used to form intermediate layers, then gas barrier properties are improved, but mass production stability is compromised
Solution Approach 1:
The label film lamination and gas barrier layer formation processes are merged into a single in-mold molding operation. The label film is disposed in the mold cavity, and the gas barrier resin is discharged through the third discharge port to form the intermediate layer in the same molding cycle, eliminating the need for separate lamination steps and improving mass production stability.
Solution Approach 2:
The label film is disposed in the mold cavity before resin injection (preliminary action), and the gas barrier resin is discharged to form the intermediate layer in a controlled sequence. This preliminary positioning of the label film and controlled discharge sequence ensure consistent gas barrier properties in mass production while simplifying the overall process.
4Weight of moving object
If the container wall is thinned to reduce weight and cost, then weight and cost are reduced, but it is technically difficult to form the intermediate layer uniformly
Solution Approach 1:
The gas barrier resin is discharged locally only at the joint portions of the label film rather than uniformly across the entire container. This allows the container walls to be thinned in non-critical areas while maintaining the intermediate layer only where gas barrier properties are essential (at the joints), thus reducing weight while avoiding uniformity issues.
Solution Approach 2:
The intermediate layer formation is segmented into discrete locations (joint portions) rather than being continuous. The third resin discharge port discharges gas barrier resin only at these specific segmented locations, allowing wall thinning in other areas while maintaining manufacturing precision at the critical joint portions.
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
This approach ensures high flexibility in gas barrier layer formation at the joint portions, enhances gas barrier properties, and allows for thinning of the container walls, improving the overall manufacturing process for mass production by maintaining stability and efficiency.
Implementation Method 1
resins are injected and fed from an injection molding nozzle of which a nozzle gate faces a container bottom forming portion of the mold, into a container inner side relative to the label film to integrate the label film with the resin
Data Source
AI summary
A thin multilayer container having favorable gas barrier properties is provided using a technique applicable to the molding of the thin multilayer container, by means of ensuring the gas barrier properties at a joint of ends of a film, when the container is molded with disposing the film having the gas barrier properties in a portion to be a container trunk portion.When molding the container with disposing in advance the film having the gas barrier properties in the portion to be the container trunk portion, while a container surface resin is fed from an injection molding nozzle into a container trunk forming portion of a mold, a gas barrier resin is fed into a position corresponding the joint of the label film as an intermediate layer between a portion of the container surface resin being spread along a core mold and a portion of the container surface resin being spread along a cavity mold.