Peelable Polyethylene Sealing Layer for Polyester Food Packaging
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Solution Overview
Problem
Existing packaging solutions for perishable food items face challenges in achieving cost-effectiveness and using simple raw materials while ensuring a reliable, peelable heat-sealed seam between a polyester tray and a cover film, as they often require complex multi-layer structures and expensive materials.
Innovation Solution
A packaging system featuring a cover film with a sealing layer composed of at least 20% polyethylene by weight, with a surface modified by corona treatment to achieve strong sealability against polyester, and optionally incorporating additional layers for enhanced properties like oxygen barrier and adhesion promotion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sealing layer with particles is used to achieve peelable sealing, then the sealing can be opened easily, but the manufacturing effort increases and the layer thickness must be very small
Solution Approach 1:
The patent uses a simple polyethylene sealing layer that forms a controlled weak bond with the polyester tray. The seal seam is designed to be separable through a defined interface, allowing the cover film to be easily removed after sealing. This approach uses inexpensive, readily available materials rather than complex particle-laden layers.
2Ease of operation
If particles are introduced into the polyester sealing layer to enable peeling, then the seal becomes separable, but the process complexity and production effort increase
Solution Approach 1:
The patent extracts the peeling function from the sealing layer composition itself and creates it through a controlled sealing process. Instead of embedding particles in the polyethylene to enable separation, the invention achieves separability through the sealing parameters and the natural interface between the seal seam and the tray edge, simplifying the material structure.
Solution Approach 2:
The patent achieves peelable sealing by optimizing sealing parameters (temperature, pressure, time) to create a controlled seal strength. The polyethylene sealing layer is sealed at specific conditions that create a bond strong enough for sealing but weak enough to allow easy separation, eliminating the need for complex particle-based mechanisms.
3Reliability
If complex multi-layer structures with copolymers and additives are used to achieve peelable sealing against polyester, then the sealing performance improves, but the raw material cost increases
Solution Approach 1:
The patent uses a homogeneous polyethylene sealing layer without complex multi-layer structures, copolymers, or additives. The simple single-material structure reduces raw material costs while achieving reliable peelable sealing through optimized sealing parameters and the natural properties of polyethylene against polyester.
4Ease of manufacture
If polyethylene is used as the sealing layer base substance, then the raw material cost decreases and processability improves, but the sealability against polyester deteriorates
Solution Approach 1:
The patent overcomes the poor sealability of polyethylene against polyester by optimizing sealing parameters (temperature, pressure, dwell time). Specific sealing conditions are established that enable reliable sealing between polyethylene and polyester, making this simple material combination viable for practical application.
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 solution enables cost-effective, reliable, and reproducible peelable sealing against polyester with adjustable seal strength and temperature stability, improving production efficiency and shelf life of packaged food.
Implementation Method 1
the sealing layer on the shell has a surface modified by corona treatment on the sealed side of the cover film
Implementation Method 2
the cover film being connected to the tray by a separable heat-sealed seam
Data Source
Figure 1
AI summary
The invention relates to packaging comprising a tray (1) and a cover film (2) covering the tray (1), wherein the tray (1) has a layer of polyester adjacent to the cover film (2), and wherein the cover film (2) has at least one sealing layer adjacent to the tray (1) made of a polymeric base substance and is connected to the tray by a separable sealing seam (5). According to the invention, the base substance comprises at least 20 wt.% polyethylene with a density of less than 0.92 g/cm², wherein the sealing layer on the side of the cover film (2) sealed to the tray (1) has a surface modified by corona treatment. The invention further relates to a method for manufacturing such packaging.