Coextruded Polyester Lidding Film for Hermetic Clean Peeling
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Solution Overview
Problem
Existing polyester-based lidding films for food packaging often fail to achieve a balance between hermetic sealing and easy opening, requiring tools for opening and risking residue contamination during tearing.
Innovation Solution
A multilayer polyester film with a heat-sealable outer layer and an inner layer comprising ethylene (meth)acrylate/methacrylic acid copolymers or anhydride modified ethylene alpha olefin copolymers, optimized to provide high hermeticity and easy opening properties when sealed to polyester containers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat sealable layer is provided on the polyester film to improve heat sealability, then hermetic sealing is achieved, but the film requires tools for opening and shows tearing when peeled off
Solution Approach 1:
The film is divided into multiple functional layers: a heat sealable polyester layer for hermetic sealing, and an inner layer containing ethylene (meth)acrylate/methacrylic acid copolymers with controlled bonding forces that enable easy opening. This segmentation allows each layer to perform its specific function optimally.
Solution Approach 2:
The invention changes the chemical composition parameters of the inner layer by incorporating ethylene (meth)acrylate/methacrylic acid copolymers with specific functional groups that provide controlled bonding forces. This parameter change enables the film to transition from requiring tools for opening to being easily openable by hand.
2Reliability
If the sealing strength is increased to ensure hermeticity, then leakage and contamination are prevented, but residues fall into the packaged product upon tearing
Solution Approach 1:
The invention modifies the chemical composition of the inner layer by incorporating ethylene (meth)acrylate/methacrylic acid copolymers with specific functional groups that provide controlled bonding forces. This parameter change ensures that the bonding is strong enough for hermetic sealing but weak enough to allow clean peeling without residue.
Solution Approach 2:
The film uses a composite structure combining polyester with ethylene (meth)acrylate/methacrylic acid copolymers in the inner layer. This composite material provides both the hermetic sealing capability of polyester and the easy opening property of the copolymer with controlled bonding forces.
3Ease of manufacture
If a heat sealable layer of lower temperature melting material is used to improve heat sealability, then sealing to polyester containers is enhanced, but the balance of bonding forces between layers is disrupted
Solution Approach 1:
Instead of using lower temperature melting materials that disrupt bonding balance, the invention changes the chemical composition parameters by incorporating ethylene (meth)acrylate/methacrylic acid copolymers. These copolymers maintain appropriate melting temperatures while providing controlled bonding forces that preserve the balance between layers.
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 hermetic sealing while allowing easy opening without tearing, ensuring user-friendly packaging with cohesive failure or delamination, and leaving a visible residue indicating tampering.
Implementation Method 1
a layer containing ethylene (meth)acrylate/methacrylic acid copolymers, optionally anhydride modified, and/or anhydride modified ethylene alpha olefin copolymers between the polyester heat sealable layer and an inner polyester layer imparts to the film excellent easy opening properties
Implementation Method 2
The film provides a hermetic and easy opening package when heat sealed onto polyester containers
Data Source
AI summary
The invention discloses a heat sealable coextruded multilayer polyester based lidding film that forms hermetic and easy opening seals onto polyester containers and its use in food packaging.