Zipper Closure Projections with Soft Sealing Material
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Solution Overview
Problem
Existing plastic storage bags with zipper-type closures face challenges in achieving a hermetic seal due to manufacturing limitations and dimensional variations, which affect the closure and sealing functionality.
Innovation Solution
The use of a plastic bag with multiple sealing and closure projections, where at least one projection is extruded from a softer plastic material different from the others, allowing for a moisture-resistant seal by creating multiple points of contact that can accommodate manufacturing variances without requiring precise tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid material is used in the extrusion of closure projections, then structural strength is improved, but hermetic sealing capability deteriorates
Solution Approach 1:
The closure projections are made from a harder plastic material for structural strength, while the sealing projections are made from a softer plastic material for hermetic sealing. This composite material approach allows each component to have optimal properties for its specific function.
Solution Approach 2:
Different regions of the closure have different material properties: the closure projections use harder material for structural support, while the sealing projections use softer material for creating the hermetic seal. This local differentiation resolves the contradiction between strength and sealing capability.
2Manufacturing precision
If tight tolerances are extruded in small plastic cross sections, then sealing precision is improved, but manufacturability deteriorates
Solution Approach 1:
The invention changes the material parameter (hardness) of the sealing projections to be softer than the closure projections. This allows the softer material to deform and accommodate dimensional variations, achieving hermetic sealing without requiring tight manufacturing tolerances.
Solution Approach 2:
The sealing projections use a softer material specifically at the sealing interface, allowing this local region to accommodate dimensional variations while the rest of the closure maintains its structural integrity. This resolves the contradiction between precision and manufacturability.
3Reliability
If soft compressible material is extruded along hooks and grooves to form gasket, then hermetic seal is improved, but manufacturing tolerance deteriorates
Solution Approach 1:
The closure uses composite materials with sealing projections made from softer plastic material that can compress to form hermetic seals, while closure projections use harder material for structural support. This allows the softer sealing material to accommodate manufacturing variations.
Solution Approach 2:
By changing the material hardness parameter of the sealing projections to be softer than the closure projections, the invention allows the sealing material to deform and compensate for manufacturing tolerances, achieving hermetic sealing without requiring precise dimensional control.
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 design effectively forms a hermetic seal by allowing for flexibility in manufacturing tolerances, ensuring the bag remains sealed despite variations in dimensions, thereby overcoming the limitations of previous designs.
Implementation Method 1
at least one of the sealing or closure projections is extruded from a plastic material which is different from and softer than a plastic material from which the other projections are extruded
Data Source
AI summary
A plastic bag having a zipper-type closure which includes opposing closure members which each has a plurality of projections. The projections of the closure members are configured for interlocking and sealing engagement when the zipper is closed. At least one of the projections on one of the closure members is in one embodiment made of a softer material than at least one of the other projections. In some embodiments, the soft projection(s) are not configured for close tolerance fit with complementary mating projections. In some embodiments, the closure is used in combination with a slider. The closure can include deformations for providing tactile or audible feedback against movement of the slider. The closure can include slider rails at a top edge margin to minimize the size of the slider.