Delamination Container EVOH Oxygen Barrier Shrinkage
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Solution Overview
Problem
Conventional delaminatable containers with EVOH layers face challenges in maintaining high oxygen barrier properties due to moisture ingress, which compromises the EVOH layer's effectiveness and increases the rigidity of the inner layer, making it difficult to shrink the inner bag effectively.
Innovation Solution
The inner bag is designed with an EVOH layer thickness of 60 to 200 µm, an inside layer of low-density polyethylene or linear low-density polyethylene with a thickness of 70 to 150 µm and a bending modulus of 200 MPa or less, and a thickness ratio of 1.5 to 4, ensuring the entire inner layer thickness is between 120 to 200 µm, optimizing oxygen barrier properties while maintaining shrinkability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the EVOH layer is made thicker to improve oxygen barrier properties, then oxygen barrier properties are improved, but the rigidity of the inner layer increases making shrinkage difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the EVOH layer (5-20 μm) and the inside layer (60-200 μm), and by controlling the bending modulus of elasticity of the inside layer (250 MPa or less). This optimization allows achieving sufficient oxygen barrier properties while preventing excessive rigidity that would hinder shrinkage.
Solution Approach 2:
The patent uses a composite structure consisting of multiple layers: outside layer (including EVOH), adhesion layer, and inside layer. This composite material approach allows each layer to contribute specific properties - the EVOH layer provides oxygen barrier properties while the inside layer (made of low-density polyethylene or linear low-density polyethylene) provides flexibility and shrinkability, achieving a balance between barrier performance and deformability.
2Reliability
If the inside layer is made thicker to prevent moisture reaching the EVOH layer, then oxygen barrier properties are maintained, but the rigidity increases making shrinkage difficult
Solution Approach 1:
The patent optimizes the thickness parameter of the inside layer to be 60-200 μm, which is sufficient to prevent moisture ingress while controlling the bending modulus to be 250 MPa or less. This parameter optimization ensures the inside layer provides adequate moisture protection without creating excessive rigidity.
Solution Approach 2:
The patent applies local quality by selecting specific materials for the inside layer (low-density polyethylene or linear low-density polyethylene) that inherently possess lower rigidity compared to other polymer options. This material selection provides the necessary moisture barrier function while maintaining local flexibility in the inside layer to enable overall shrinkage.
Data Source
Figure 1A~1B
Figure 2
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AI summary
Provided is a delamination container having improved oxygen barrier properties. The present invention provides a delamination container provided with a container body having an outer shell and an inner pouch, the inner pouch being adapted to delaminate from the outer shell and contract in association with a decrease of the contents, wherein the inner layer constituting the inner pouch is provided with, in order from the container outer surface side, an outside layer, an adhesive layer, and an inside layer. The outside layer includes an EVOH layer, and the inside layer has a thickness of 60-200 µm and a flexural modulus of 250 MPa or less, the value (thickness of the inside layer/thickness of the EVOH layer) being 1.1-5, and the total thickness of the inside layer being 100-250 µm.