Recyclable Polypropylene Bag Sealing with Low-Temp Adhesive
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Solution Overview
Problem
Traditional multi-wall paper and polymer laminate bags are heavy, expensive, prone to tearing, and not recyclable, leading to significant waste and environmental issues, while existing hot melt adhesives are not suitable for sealing polymeric bags without damaging them.
Innovation Solution
Development of polymeric bags made entirely of recyclable polypropylene with heat-activated adhesive layers that can be sealed at temperatures below the softening point of the polymeric material, using existing production equipment, and modification of hot air sealer equipment to distribute heat evenly across the bag for effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional multi-wall paper and polymer laminate bags are used, then sealing can be achieved with existing hot melt adhesives, but the bags become heavy, expensive, and prone to tearing
Solution Approach 1:
The patent changes the material parameters by using woven polypropylene fabric instead of traditional multi-wall paper and polymer laminate construction. This material substitution reduces bag weight while maintaining or improving strength and durability characteristics.
2Reliability
If existing hot melt adhesives are used for sealing, then sealing can be achieved, but the adhesive temperatures exceed the softening point of polymeric bag material causing deformation
Solution Approach 1:
The patent changes the thermal parameters by selecting adhesive materials with lower melt temperatures that can be activated below the softening point of polypropylene (approximately 148.89°C or 300°F). This allows effective sealing without causing bag deformation.
Solution Approach 2:
The patent introduces a hot air sealer equipment as an intermediary device that provides controlled heat activation of the adhesive. The equipment distributes hot air evenly across the bag surface to activate the adhesive at controlled temperatures below the polymeric material's softening point.
3Reliability
If typical hot air sealer equipment is used, then sealing can be achieved, but the equipment causes bag deformation due to excessive heat
Solution Approach 1:
The patent modifies the operational parameters of the hot air sealer equipment by reducing the heat activation temperature from typical settings (exceeding 204.44°C or 400°F) to below the softening point of polypropylene (approximately 148.89°C or 300°F). This parameter change eliminates bag deformation while maintaining sealing effectiveness.
Solution Approach 2:
The patent introduces a modified hot air sealer equipment as an intermediary that provides controlled, even heat distribution across the bag surface. This modified equipment acts as a mediator between the sealing requirement and the bag material's thermal sensitivity.
4Ease of manufacture
If traditional bag materials are used, then existing sealing equipment can be used, but significant waste and environmental issues occur
Solution Approach 1:
The patent changes the material composition parameters by using woven polypropylene fabric, which is recyclable and environmentally friendly compared to traditional multi-wall paper and polymer laminate bags. This material change reduces waste and environmental impact while maintaining manufacturing compatibility through adaptation of existing sealing equipment.
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 results in lighter, more durable, and recyclable bags that reduce waste and environmental impact, while allowing for efficient sealing without damaging the polymeric material, thus addressing the limitations of traditional bags and existing sealing technologies.
Implementation Method 1
activating the first adhesive layer and the second adhesive layer by applying heat at a temperature below the softening point temperature of the polymeric material
Implementation Method 2
modification of hot air sealer equipment to distribute heat evenly across the bag for effective sealing
Data Source
AI summary
A method and apparatus for sealing a bag made of a polymeric material by applying heat activated layers on different portions of the bag, wherein the first adhesive layer and the second adhesive layer have respective heat activation temperatures below the softening point temperature of the polymeric material; creasing the bag along a fold line, applying heat at a temperature below the softening point temperature of the polymeric material to activate the first adhesive layer and the second adhesive layer to adhesive states after the bag has been filled with contents; and folding the bag to form an adhesive-to adhesive seal by contact between the heat activated first adhesive layer and the heat activated second adhesive layer.