Profiled Sealing Edge for Contamination-Resistant Packaging
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Solution Overview
Problem
Packaging trays with thermoformed plastic sheets face contamination issues at the sealing edge during food filling, leading to unreliable bonding with the sealing film, especially at high packaging speeds.
Innovation Solution
The sealing edge is designed with a profiling that includes projections (ribs) and depressions, where the depressions act as receiving volumes for contaminations, allowing the projections to maintain contact with the sealing film for reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing edge is made smooth and continuous for easy bonding, then bonding reliability is improved, but contamination from food filling easily adheres to the sealing edge
Solution Approach 1:
The sealing edge is segmented into alternating projections and depressions along its length. The projections provide discrete bonding contact points that maintain sealing film adhesion, while the depressions create gaps that prevent continuous contamination adhesion. This segmentation allows the sealing edge to simultaneously achieve reliable bonding at projection points while resisting contamination in the depression regions.
Solution Approach 2:
Different regions of the sealing edge are given different functions: the projections are designed with bonding-contact surfaces that have high affinity for the sealing film material, while the depressions are designed with geometry that promotes contamination collection and prevents bonding interference. This local differentiation allows each region to optimize its specific function.
2Productivity
If the packaging speed is increased for higher productivity, then output is improved, but contamination of the sealing edge during filling becomes more severe
Solution Approach 1:
The profiling of the sealing edge with projections and depressions is prepared in advance during tray manufacturing, before the filling operation occurs. This preliminary structural preparation ensures that when high-speed filling occurs, the contaminations are directed into the pre-formed depression regions rather than spreading across the entire sealing edge, maintaining bonding reliability despite high packaging speeds.
3Ease of manufacture
If the sealing edge structure is simplified for ease of manufacture, then manufacturing complexity is reduced, but resistance to contamination is compromised
Solution Approach 1:
The formation of the profiling (projections and depressions) is merged with the existing thermoforming process that creates the packaging tray body. The same mold that forms the tray walls and base is modified to include profiling features that are created during the single-shot thermoforming operation. This integration eliminates the need for separate profiling steps while maintaining contamination resistance.
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 profiling effectively prevents contaminations from interfering with the bonding process, ensuring a reliable and hermetic seal of the packaged food, even under conditions of contamination.
Implementation Method 1
a heated sealing or bonding bar conventionally presses onto the sealing film in the region of the contact surface and displaces the contaminations located therebelow
Implementation Method 2
presses onto the sealing film in the region of the contact surface and displaces the contaminations
Implementation Method 3
a good connection and sealing is obtained by the use of pressure and/or heat
Implementation Method 4
a good connection and sealing is obtained by the use of pressure and/or heat
Data Source
AI summary
The invention relates to a packaging tray (1), produced from a thermoformed plastics sheet, with a base (10), sidewalls (11, 12) and a sealing edge (13) which is formed peripherally on the upper side of the sidewalls (11, 12) and onto which a sealing film (2) can be placed and can be bonded to the sealing edge (13), in which the sealing edge (13) is formed with a contact surface, which is provided for supporting the sealing film, with a profiling in the form of projections (133) in each case forming part of the contact surface and with depressions (134) which run between adjacent projections (133) and interrupt the contact surface, wherein the depressions (134) in each case define a receiving volume.