Multi-chamber Container Weak Seal Strength Control
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Solution Overview
Problem
Existing compartmented containers with weakly sealed parts fail to withstand sterilization at 121° C without deformation and have limited adjustability in seal strength, which is crucial for varying content weights, and lack sufficient transparency and drop strength.
Innovation Solution
A compartmented container formed from a resin film or sheet with a heat-sealable layer composed of a specific propylene copolymer composition, allowing for adjustable seal strength and high heat resistance, along with a laminated structure for enhanced transparency and drop strength, enabling easy and free control of seal strength based on content weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a seal layer is formed from a mixture of linear low-density polyethylene resin and polypropylene resin, then the weakly sealed part can be easily broken by hand or jig, but the container softens during sterilization at 121° C., resulting in breakage or deformation
Solution Approach 1:
The patent changes the chemical composition parameters of the seal layer by replacing polyethylene/polypropylene mixtures with specific propylene copolymer compositions (containing 5-20 wt% ethylene and/or C4-8α-olefin). This parameter change maintains ease of breaking at room temperature while providing sufficient heat resistance for sterilization at 121° C.
Solution Approach 2:
The patent uses composite material strategy by creating a seal layer from propylene copolymer with controlled copolymerization of ethylene and/or C4-8α-olefin. This composite structure at molecular level provides both the weak seal strength needed for easy breaking and the thermal stability required for sterilization resistance.
2Strength
If the seal strength of the weakly sealed part is made high to prevent breakage during dropping, then the container passes the drop test, but the weakly sealed part takes a long time to break for internal mixing
Solution Approach 1:
The patent adjusts the ethylene and/or C4-8α-olefin content parameter within 5-20 wt% range to optimize the balance between seal strength and breakability. This parameter optimization enables the weakly sealed part to resist dropping impacts while remaining breakable within a practical time frame for internal mixing.
3Ease of operation
If the seal strength of the weakly sealed part is made low to enable easy breaking, then the weakly sealed part breaks quickly for internal mixing, but the container fails the drop test for larger contents (500 mL or more)
Solution Approach 1:
The patent optimizes the propylene copolymer composition parameters (specifically 5-20 wt% ethylene and/or C4-8α-olefin content) to achieve a seal strength that simultaneously satisfies both the ease of breaking for internal mixing and the drop test requirements for containers with 500 mL or more of content.
4Ease of manufacture
If conventional polymer compositions (polyethylene and olefin block copolymer or polypropylene-based polymer and styrene-based elastomer) are used for the heat-sealable layer, then the container can be heat-sealed, but the compositions are poor in heat resistance and unsuitable for sterilization at 121° C.
Solution Approach 1:
The patent changes the polymer composition from conventional heat-sealable materials (polyethylene/olefin block copolymer or polypropylene/styrene elastomer) to a specific propylene copolymer with controlled ethylene and/or C4-8α-olefin content (5-20 wt%). This parameter change maintains heat-sealing capability while achieving sufficient heat resistance for sterilization at 121° C.
Solution Approach 2:
The patent employs composite material strategy by creating a propylene copolymer with specific copolymerization ratios. This molecular-level composite structure provides both the heat-sealing properties needed for manufacturing and the thermal stability required for sterilization 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
The container maintains stable weak seal strength after sterilization, provides optimal seal strength and drop impact resistance, and ensures easy handling and sealing, addressing the limitations of existing technologies by offering a wide range of heat-sealing temperatures and improved transparency.
Implementation Method 1
the opposing inner walls are heat-sealed partially and peelably to form the weakly sealed part
Implementation Method 2
the container maintains stable weak seal strength after sterilization, provides optimal seal strength and drop impact resistance
Data Source
AI summary
Multi-chamber container (1) having its interior partitioned by weak seal portions (3) provided through detachable heat sealing so that multiple contents are accommodated separately from each other, wherein use is made of heat seal layers consisting of a composition comprising two types of propylene copolymers components (component A and component B) from propylene and ethylene and/or a C4-C8 α-olefin which have the following elution properties. Thus, a region wherein a change of seal strength by a change of heat seal temperature is small has a wide temperature range to thereby facilitate controlling of the seal strength at the weak seal portions. The proportion (mass %) of, to total solution, elution according to the TREF method (temperature: 0 to 140° C. and solvent: ODCB) is as follows. With respect to component A: 15 to 50 at 0° C., and 5 to less than 15 at 60 to 90° C. With respect to component B: 0 to 25 at 0° C., and 15 to 70 at 60 to 90° C.