Double-Wall Closure In-Shell Sealing Liner
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Solution Overview
Problem
Existing double-wall closures with induction-heated foil seals are difficult for consumers to manipulate, lead to distortion of the container top, and are costly to sterilize, especially in aseptic applications.
Innovation Solution
A double-wall closure configuration with an inner and outer annular skirt portion, allowing for in-shell compression molding of a sealing liner, eliminating the need for induction foil seals and facilitating easier consumer use and sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If induction-heated foil seals are used for sealing, then hermetic sealing is achieved, but consumer manipulation difficulty increases and container top distortion occurs
Solution Approach 1:
The patent removes the induction-heated foil seal from the system and replaces it with a thermoplastic sealing liner that is compression-molded directly into the closure. This extraction eliminates the problematic heating process while maintaining sealing functionality through the flexible thermoplastic material that conforms to the container opening.
Solution Approach 2:
The patent replaces the thermal/electromagnetic sealing mechanism (induction heating) with a mechanical compression molding process. The thermoplastic liner is formed by compression molding under heat and pressure, then cools to create a rigid yet sealed structure, substituting thermal activation with mechanical forming.
2Reliability
If induction-heated foil seals are used, then sealing is achieved, but container top surface distortion occurs
Solution Approach 1:
The patent extracts the induction heating process entirely from the sealing system. By using a thermoplastic liner that is compression-molded and then cooled, the heating step is removed, eliminating the thermal expansion and subsequent contraction that causes the container top surface to distort.
Solution Approach 2:
The patent changes the thermal parameters of the sealing process. Instead of rapid induction heating followed by cooling (which causes distortion), the system uses controlled compression molding with gradual heating and cooling, maintaining dimensional stability of the container top surface throughout the process.
3Reliability
If foil seal liners are used, then hermetic sealing is achieved, but sterilization difficulty increases and secondary heating systems are required
Solution Approach 1:
The patent extracts the foil seal liner material and replaces it with a thermoplastic material that can be sterilized using standard autoclaving or other conventional methods. This eliminates the need for specialized secondary heating systems and simplifies the sterilization process to a single, integrated step.
Solution Approach 2:
The patent changes the material parameters of the sealing liner from foil-based to thermoplastic-based, which fundamentally alters the sterilization requirements. The thermoplastic material can withstand and be sterilized by moisture heat, steam, or other conventional methods without requiring separate heating systems, thereby simplifying manufacturing.
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 provides a convenient, cost-effective, and easily sterilizable closure that maintains a hermetic seal without secondary operations, enhancing consumer access and reducing bottling costs.
Implementation Method 1
A closure embodying the principles of the present invention has been configured to permit efficient in-shell compression molding of a sealing liner adjacent the inside surface of a top wall portion of the closure
Data Source
AI summary
A composite closure having a double-wall configuration facilitates convenient use by consumers, and permits in-shell formation of a sealing liner. The closure includes an outer closure cap having inner and outer annular skirt portions arranged in concentric relationship with each other. The closure includes a sealing liner formed in the closure cap at the inside surface of the top wall portion of the closure cap. A method of compression-molding the sealing liner is provided.