Flexible Packaging Weld Zone Surface Continuity
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Solution Overview
Problem
The manufacturing of tubular packagings with high percentages of recycled material or renewable resources faces challenges due to discontinuities in the weld zone, leading to defects such as leaks and visible imperfections during assembly, as these materials are difficult to compress and may not be suitable for food contact.
Innovation Solution
The introduction of an additional weldable material on the internal face of the tubular body at the weld zone to smooth the surface, enhance weldability, and prevent migration of unsuitable substances, which can be applied during or after welding and may include a multilayer structure to improve barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laminates with high recycled material or renewable resources content are used to manufacture tubular bodies by welding, then the environmental sustainability is improved, but the weld zone exhibits discontinuities that cause assembly defects
Solution Approach 1:
A virgin polymer layer is introduced as an intermediary between the recycled/renewable laminate layers. This intermediary layer is applied to the internal face of the tubular body at the weld zone, providing a continuous, smooth surface that eliminates discontinuities while allowing the outer laminate to maintain its high recycled content for environmental sustainability.
Solution Approach 2:
The virgin polymer material is applied locally only at the weld zone on the internal face of the tubular body, rather than throughout the entire structure. This localized application resolves the discontinuity issue at the critical weld area while minimizing the impact on overall recycled material content and reducing additional material usage.
2Ease of manufacture
If the weld zone is compressed to improve material fluidity and weldability, then the welding process is improved, but unsuitable substances migrate to the internal face of the packaging
Solution Approach 1:
The virgin polymer layer serves as a barrier intermediary between the weld zone and the product-containing interior. It prevents the migration of unsuitable substances from the compressed recycled material to the internal face, while still allowing the compression welding process to proceed effectively on the outer laminate structure.
Solution Approach 2:
The packaging structure is segmented into distinct functional zones: the outer laminate layers for structural integrity and sustainability, the weld zone for joining, and the internal virgin polymer layer for barrier protection. This segmentation allows each zone to perform its specific function without interfering with others.
3Manufacturing precision
If additional weldable material is applied to the internal face at the weld zone, then the discontinuity is removed and assembly is improved, but the device complexity increases
Solution Approach 1:
The solution changes the material parameter (using virgin polymer) and the location parameter (internal face at weld zone) to achieve surface continuity. By modifying these parameters locally rather than changing the entire structure, the complexity increase is minimized while effectively resolving the discontinuity issue.
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
This solution effectively reduces discontinuities, improves the assembly process, and ensures the packaging's integrity and safety for food contact by making the internal surface smooth and continuous, thereby enhancing the packaging's strength and appearance.
Implementation Method 1
an additional material, in particular making it weldable to the internal surface of the tubular body
Implementation Method 2
the head and the tube body are then welded to one another
Data Source
AI summary
The invention relates to an essentially tubular flexible packaging intended for containing a semi-liquid or pasty product, which includes an apron, a head, an added piece of material at least on the inside of the apron, and optionally a lid, the apron consists of a rolled-up sheet and includes a longitudinal weld for assembling the edges thereof together, and the head being attached to the edge of one of the ends of the apron. The apron includes a ratio of at least 30% of recycled material or material from renewable resources, and the added piece of material is arranged so as to eliminate a discontinuity in the inner surface in the area of the longitudinal weld.