Overmolded Polymer Dispensing Closure Prevents Metal Oxidation
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Solution Overview
Problem
Existing dispensing containers for viscous fluid products face issues such as exposed oxidizable metal edges, sharp cut edges causing injury, mispositioning of self-adhesive films, and uncontrolled flow due to insufficient stiffness of plastic tips, leading to oxidation, safety hazards, and manufacturing inefficiencies.
Innovation Solution
A unitary dispensing closure with a generally annular metal ring and an overmolded polymer layer that covers the central opening, preventing oxidation and injury, and providing controlled flow through resiliently flexible apertures, eliminating the need for separate parts and precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stamped metal end with a central opening is used, then the opening allows controlled flow of product, but the cut edge exposes oxidizable metal that can contact food product and cause injury
Solution Approach 1:
A polymer ring is introduced as an intermediary component between the metal end and the food product. This polymer ring covers the exposed metal cut edge, preventing direct contact between the oxidizable metal and the food product, while also providing a safe, non-sharp surface that prevents injury. The polymer ring acts as a protective mediator that maintains the functional opening while eliminating the harmful exposed metal edge.
Solution Approach 2:
The closure is designed as a composite structure combining metal and polymer materials. The metal end provides structural strength and the opening for controlled flow, while the polymer ring provides protection against oxidation and injury. This composite approach allows each material to contribute its advantageous properties to the overall closure system.
2Reliability
If a self-adhesive plastic film is used to cover the metal end opening, then the opening can be sealed, but precise positioning of the film is difficult in automated manufacturing
Solution Approach 1:
The polymer ring is integrated directly with the metal end through overmolding, merging two separate components into a single unified structure. This integration eliminates the need for separate adhesive application and positioning operations, ensuring precise and consistent positioning of the polymer ring relative to the metal end opening in automated manufacturing processes.
Solution Approach 2:
The adhesive bonding mechanism is replaced with a mechanical overmolding process. Instead of relying on adhesive placement precision, the polymer ring is molded directly onto the metal end, creating a permanent, precisely positioned joint that is inherently more suitable for automated manufacturing environments.
3Ease of manufacture
If a thin plastic film with X-shaped cuts is used, then the film can be simple to manufacture, but the flexible tips lack sufficient stiffness to form an effective valvular aperture
Solution Approach 1:
The geometry of the aperture is changed from simple X-shaped cuts to a circular opening with radially extending flexible tips. This parameter change in the aperture shape provides the necessary stiffness to the flexible tips while maintaining ease of manufacture. The radial configuration of the tips creates a more stable structure that can effectively control product flow while being simple to form in the polymer ring.
4Ease of manufacture
If separate pieces (metal end and plastic disk) are used, then each component can be manufactured independently, but positioning and seaming to the container body is difficult and costly
Solution Approach 1:
The metal end and polymer ring are merged into a single integrated component through overmolding. This eliminates the need for separate positioning and seaming operations between two components, reducing manufacturing complexity and cost while maintaining the ability to manufacture each material type independently through the overmolding process.
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 prevents oxidation and injury, ensures precise control over fluid flow, and reduces manufacturing complexity and costs by using a single, assembled component with enhanced mechanical interlocking and adjustable aperture configurations for tailored dispensing.
Implementation Method 1
the cut edge exposes the oxidizable metal, and this bare metal edge can come into contact with the food product
Implementation Method 2
The aperture tends to open too easily and quickly when the product is pressurized, and tends to close too slowly when the pressure is released
Data Source
AI summary
A dispensing closure for a dispensing container (1) and a dispensing container (1) incorporating such a dispensing closure, wherein the closure has a unitary type of construction. The dispensing closure includes a generally annular metal ring (4) having an outer peripheral edge and a central opening encircled by an inner peripheral edge (6), the ring being attached to the edge of the container body side wall at one end of the container body; and an overmolded polymer layer (16) having an annular outer portion molded over the inward surface of the ring and having a central panel integrally formed with the outer portion so as to cover the central opening in the ring (4), the central panel of the polymer layer (16) defining at least one aperture (7) through which the product in the container body can be dispensed.