Peelable Vacuum Skin Packages Surface Tension Seal
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Solution Overview
Problem
Existing vacuum skin packaging technologies make it difficult for consumers to open packages without using sharp objects, as the seal between the thermoplastic film and the polyester substrate is strong and not easily peelable.
Innovation Solution
The development of thermoplastic films with surface-treated exterior surfaces having a surface tension between 36-60 dynes/cm, allowing for a peelable seal with a seal strength of 0.5-6 lb./in. when sealed to a polyester substrate under vacuum, enabling easy opening without tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a strong seal is formed between the thermoplastic film and polyester substrate, then packaging reliability is improved, but package openability deteriorates
Solution Approach 1:
The film structure incorporates different layers with distinct properties: an outer layer providing strong seal adhesion to the polyester substrate for reliable sealing, and an inner layer providing controlled peelability for easy opening. This local differentiation of material properties resolves the contradiction between strong sealing and easy openability.
Solution Approach 2:
The invention uses a composite film structure consisting of multiple polymer layers (including polyolefin, polyester, and polyamide layers) with different adhesion characteristics. The composite structure enables the seal interface to exhibit both strong initial bonding for packaging integrity and controlled delamination for consumer opening.
2Strength
If the seal strength is increased to withstand packaging conditions, then packaging durability is improved, but consumer openability deteriorates
Solution Approach 1:
The invention controls the seal strength parameter by adjusting the surface energy and composition of the film layers. The outer layer is designed to form seals within a specific strength range (0.5-4.0 lb/in) that is sufficient for packaging durability but low enough to allow consumer opening without tools.
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 provides a vacuum skin package that is easily openable by consumers, maintaining sufficient seal strength to withstand packaging, distribution, and storage conditions.
Implementation Method 1
a peelable seal therebetween is provided by a vacuum or pressure of less than 1 x 10^5 pa which seals the first surface to the polyester substrate
Data Source
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AI summary
The present invention describes vacuum skin packages comprising a thermoplastic film and a polyester substrate wherein the thermoplastic film includes at least a first polymer layer having a first surface and an opposing second surface and comprises an ethylene/unsaturated ester copolymer, wherein the first surface has been surface treated in a manner to exhibit a surface tension of between 36-60 dynes/cm. The thermoplastic film is adapted to form a peelable seal between the first surface of the first polymer layer of the thermoplastic film and the polyester substrate by a pressure of less than 1 × 10 5 Pa applied therebetween, wherein the peelable seal has a seal strength of between 0.5-6 1b./in. (0.09-1.08 kg/cm).