Multi-Seal Container Lid for Moisture Tightness With Low Opening Force
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Solution Overview
Problem
Existing containers for moisture-sensitive products like pharmaceuticals and diagnostic test strips fail to provide a reliable moisture-tight seal after multiple cycles of opening and closing, often requiring high opening forces and adding to manufacturing costs due to the need for desiccants.
Innovation Solution
A container design featuring a combination of thermoplastic-to-thermoplastic and elastomer-to-thermoplastic seals, created through multi-shot injection molding, which reduces moisture vapor transmission while maintaining a low opening force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single seal is used between the lid and body, then the container structure is simple and manufacturing cost is low, but the moisture-tightness becomes unreliable after multiple opening and closing cycles
Solution Approach 1:
The sealing system is divided into multiple independent seals (first seal and second seal) arranged in series between the lid and body. Each seal performs a specific sealing function, and their combination provides redundant moisture protection that maintains reliability after multiple opening and closing cycles.
Solution Approach 2:
The container employs composite sealing structures where different seal materials (e.g., elastomer and thermoplastic) are combined to work together. The first seal and second seal use different material properties to complement each other, providing both initial sealing and sustained moisture-tightness over time.
2Reliability
If a strong seal is used to ensure moisture-tightness, then the sealing reliability is improved, but the opening force required becomes too high
Solution Approach 1:
The total sealing force is distributed across multiple seals rather than concentrated in a single strong seal. Each seal engages at different stages during the opening process, allowing the container to maintain strong overall sealing while reducing the peak opening force required at any single moment.
Solution Approach 2:
The seals are designed to engage and disengage in a sequential manner during opening and closing operations. The first seal engages initially, followed by the second seal, creating a dynamic sealing process that adapts to the opening force applied and provides progressive sealing engagement.
3Reliability
If desiccant material is added to absorb moisture, then the moisture protection is improved, but the manufacturing cost increases
Solution Approach 1:
The sealing function is extracted and enhanced through the multi-seal mechanism, which actively prevents moisture ingress at the seal interface. This reduces the reliance on passive desiccant materials for moisture absorption, allowing for reduced desiccant volume and lower manufacturing costs while maintaining the moisture budget.
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 combined seals provide enhanced moisture-tightness and reduced opening force, minimizing the need for desiccants and lowering manufacturing costs, while ensuring the integrity of moisture-sensitive contents over multiple cycles.
Implementation Method 1
The elastomeric sealing surface includes an elastomeric ring that is configured to be compressed by an upper surface of a rim surrounding the opening when the lid is in the closed position. Vertical compression of the elastomeric ring causes a portion of the ring to elastically expand radially into a void provided between the body and the lid.
Data Source
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AI summary
A moisture tight container (100) includes a container body (101) and a lid (120) preferably linked to the body by a hinge (140). The body and lid include at least a first seal (B) and a second seal (C) in series to provide a moisture tight seal between the body and the lid. The first seal includes mating of thermoplastic-to-thermoplastic sealing surfaces of the body and lid respectively. The second seal includes mating of thermoplastic-to-elastomeric sealing surfaces of the body and lid, respectively, or of the lid and body, respectively.