Multi-layer Paper Packaging Bag Flap for Reusable Adhesive Sealing
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Solution Overview
Problem
Existing paper packaging bags with adhesive connections are not reusable without causing damage, as the adhesive bond cannot be removed without tearing or damaging the flap.
Innovation Solution
A multi-layer flap design with a reinforcing strip and a release agent applied to the adhesive surface, allowing the flap to be repeatedly opened and sealed without visible or functional damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer paper flap is used with adhesive connection, then the packaging bag can be sealed, but the adhesive bond cannot be removed without tearing or damaging the flap
Solution Approach 1:
The flap is divided into multiple layers (at least two layers) with different properties. The first layer provides a smooth adhesive surface, while the second layer provides strength and resistance to tearing. This segmentation allows the adhesive to bond to the smooth first layer without damaging the stronger second layer during removal and reapplication.
Solution Approach 2:
The flap uses a composite structure combining different paper layers or materials with complementary properties. One layer is optimized for adhesive bonding (smooth surface), while another layer provides mechanical strength (tear resistance). This composite approach resolves the contradiction between ease of manufacturing and reusability.
2Strength
If adhesive is applied directly to the paper surface, then the flap can be bonded to the front part, but removing the adhesive causes paper fibers to tear and cover the adhesive surface
Solution Approach 1:
Different areas of the flap have different properties: the first layer provides a locally optimized smooth surface for adhesive contact, while the second layer provides overall structural strength. This local differentiation allows strong bonding without fiber tearing during removal.
Solution Approach 2:
The multi-layer structure is prepared in advance before adhesive application. The smooth first layer is positioned to contact the adhesive, preventing fiber tearing before it can occur during the bonding and subsequent removal process.
3Device complexity
If the flap is made from single-layer paper, then the packaging bag is simple to manufacture, but the flap lacks sufficient strength to be removed and reattached multiple times
Solution Approach 1:
The flap is segmented into multiple layers where the second layer specifically provides tear resistance. This segmentation adds minimal construction complexity while dramatically improving the flap's ability to withstand repeated adhesive removal and reapplication.
Solution Approach 2:
The flap uses composite paper layers or combinations of paper and other materials to achieve both strength and flexibility. The composite structure provides the necessary mechanical properties for reusability without excessive complexity in manufacturing.
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 multi-layer flap design and release agent enable the packaging bag to be opened and resealed multiple times without tearing or leaving adhesive residue, maintaining adhesive strength and flap integrity.
Implementation Method 1
a release agent is applied to the adhesive surface of the flap, wherein the release agent reduces adhesion to the adhesive trace
Data Source
Figure 1
AI summary
The invention relates to a packaging bag with a back part (1) and a front part (2, 2a, 2b) which are connected to each other at the lower end (3) and at the sides (4) and which form a closable opening at their upper end region in that the back part (1) projects upwards over the upper end of the front part (2), wherein the projecting area (1a) of the back part (1) forms a flap (5) which can be folded over onto the front part (2) and can be bonded to the front part (2) by means of an adhesive strip (6), and wherein the front part (2) and back part (1) are made entirely of paper, wherein the flap (5) is multi-layered.