Polypropylene Multi-Cell Container Cut-Score for Smooth Cell Separation
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Solution Overview
Problem
Current multi-cellular food packaging containers made from polystyrene are not suitable for all food applications due to their poor moisture barrier properties and tendency to crack, and attempts to create similar containers from polypropylene result in rough, sharp edges that can injure users.
Innovation Solution
A polypropylene multi-cellular container with a separable region connecting cells, featuring varying cut-score depths and star-cut patterns to ensure smooth edges and consistent tearability, allowing individual cells to be removed without sharp edges or snagging hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polypropylene is perforated to create separable regions, then multi-cellular containers can be made from a more suitable material, but rough and sharp edges are created that can injure users
Solution Approach 1:
The patent applies different cut depths at different locations within the separation region. The first cut extends through the entire thickness of the wall, while the second cut extends only partially through the thickness. This creates a localized quality difference that allows the separation region to tear cleanly without creating sharp edges, resolving the contradiction between material suitability and user safety
Solution Approach 2:
The patent pre-forms the separation region with two cuts of different depths before the container is used. This preliminary action creates a controlled tear path that will naturally produce smooth edges when the container is separated, preventing the creation of sharp edges that could injure users
2Ease of operation
If polystyrene is used for multi-cellular containers, then portion-control packaging can be achieved, but the material forms a poor moisture barrier and is brittle
Solution Approach 1:
The patent changes the material parameter from polystyrene to polypropylene, which has superior moisture barrier properties and structural integrity. The invention then adjusts the cut depth parameters within the separation region to ensure the new material can still be easily separated into portions, maintaining ease of operation while improving reliability
3Ease of manufacture
If uniform cut-scores are used in all directions, then manufacturing is simplified, but tearability consistency varies with plastic material orientation
Solution Approach 1:
The patent applies different cut depths based on the orientation relative to the plastic material's index direction. Cuts oriented in the index direction extend to a first depth, while cuts oriented perpendicular to the index direction extend to a second depth. This local quality adjustment ensures consistent tearability across different orientations while maintaining manufacturability
Data Source
AI summary
A multi-cellular polypropylene container with a cut-scored region connecting the cells of the container is described. By varying the cut-score depths depending on the orientation of the plastic material, greater consistency in the tearability of the individual cells is achieved. One or more star-cut patterns may be provided between the cells. The star-cut patterns have curved edges that lead to the separation region. The curved edges provide a generally smooth surface that does not cut or snag the user.