Multilayer Vacuum Skin Film for Humidity-Resistant Oxygen Barrier
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Solution Overview
Problem
Existing vacuum skin packaging (VSP) films face challenges in maintaining effective oxygen barrier properties under high humidity conditions due to the sensitivity of ethylene vinyl alcohol (EVOH) layers, requiring thick layers that increase polymer use and cost, while also needing to be formable and ovenable/microwavable.
Innovation Solution
Incorporating a layer of high moisture barrier polymer, such as HDPE, between the sealant and EVOH gas barrier in a multilayer film structure to reduce EVOH thickness and enhance oxygen barrier properties, with an asymmetrical layer configuration to prevent moisture from reaching the EVOH layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick EVOH barrier layer is used to maintain oxygen barrier properties under high humidity conditions, then the oxygen barrier performance is improved, but the polymer usage and cost increase
Solution Approach 1:
A moisture barrier layer (such as HDPE, PP, or COC) is introduced as an intermediary between the sealant layer and the EVOH barrier layer. This intermediate layer blocks moisture from reaching the EVOH layer, preventing humidity-induced degradation of oxygen barrier properties. As a result, thinner EVOH layers (reducing polymer usage) can maintain effective oxygen barrier performance even in high humidity environments.
Solution Approach 2:
The packaging film is designed as a composite multilayer structure combining different materials with complementary functions: a sealant layer for sealing, a moisture barrier layer (HDPE/PP/COC) to block moisture, and an EVOH layer for oxygen barrier. This composite structure allows each layer to perform its specific function optimally, enabling reduced EVOH thickness while maintaining overall barrier performance.
2Reliability
If a thick EVOH barrier layer is used to ensure oxygen barrier properties under high humidity conditions, then the oxygen barrier performance is improved, but the manufacturing cost increases
Solution Approach 1:
The moisture barrier layer (HDPE, PP, or COC) serves as a protective intermediary that shields the EVOH layer from moisture exposure. This allows the EVOH layer to be thinner and less expensive while still maintaining effective oxygen barrier properties, thereby reducing manufacturing costs without compromising barrier performance.
Solution Approach 2:
The multilayer composite structure distributes the barrier functions across different materials, allowing the EVOH layer to be optimized for oxygen barrier at reduced thickness. The moisture barrier layer handles moisture protection, enabling cost-effective manufacturing by reducing the quantity and cost of EVOH material required.
3Quantity of substance
If the EVOH layer is made thinner to reduce polymer usage, then the oxygen barrier performance may be maintained, but the layer becomes more sensitive to humidity effects
Solution Approach 1:
The moisture barrier layer (HDPE, PP, or COC) acts as a protective intermediary that prevents humidity from reaching the thinner EVOH layer. This intermediary layer decouples the EVOH layer from humidity exposure, allowing the EVOH to be made thinner without compromising its resistance to humidity effects or maintaining effective oxygen barrier performance.
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 film achieves improved oxygen barrier performance with reduced EVOH thickness, extending shelf life of packaged products and maintaining effectiveness under varying humidity conditions, while being formable and suitable for oven or microwave use.
Implementation Method 1
Incorporating a layer of high moisture barrier polymer, such as HDPE, between the sealant and EVOH gas barrier in a multilayer film structure to reduce EVOH thickness and enhance oxygen barrier properties
Implementation Method 2
The film achieves improved oxygen barrier performance with reduced EVOH thickness, extending shelf life of packaged products
Data Source
AI summary
The present invention relates to packaging films, more specifically to packaging films useful in vacuum skin packaging applications characterized by excellent oxygen barrier properties, to a method of packaging by using said films and to packages obtained therewith.