Flexible Standing Ring Mold for PET Container Vacuum Integrity
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Solution Overview
Problem
Conventional PET containers face challenges in maintaining material integrity and clarity while achieving high crystallinity, which affects their structural integrity and weight optimization, especially under vacuum and loading conditions.
Innovation Solution
A mold design that forms a plastic container with an integrally formed flexible standing ring, allowing for increased vacuum absorption and reduced material consumption by incorporating a base fold that is flexible vertically and rigid radially, thereby enabling thinner wall thicknesses and improved structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal processing is used to increase PET crystallinity for improved structural integrity, then the container becomes more opaque and loses clarity
Solution Approach 1:
The patent applies different processing conditions to different regions of the container. The base region undergoes thermal processing to achieve high crystallinity (30-50%) for structural support, while the sidewall regions maintain biaxial orientation with lower crystallinity (20-35%) to preserve clarity. This localized quality differentiation resolves the contradiction between structural integrity and optical clarity.
Solution Approach 2:
The container is segmented into functionally distinct regions: a base portion with high crystallinity for vacuum resistance and sidewall portions with optimized clarity. The mold design creates separate cavities for the base and sidewall, allowing independent processing optimization for each segment to address both strength and clarity requirements.
2Weight of moving object
If wall thickness is reduced to decrease container weight, then the container loses structural integrity under vacuum and loading conditions
Solution Approach 1:
The patent changes the crystallinity parameter in the base region to 30-50%, which dramatically improves the material's mechanical properties and vacuum resistance. This parameter change allows the use of thinner wall sections while maintaining structural integrity, as the highly crystalline base provides the necessary strength without requiring increased thickness.
Solution Approach 2:
The container effectively uses a composite structure with two distinct material states: a highly crystalline base portion (30-50% crystallinity) for structural support and a less crystalline sidewall portion (20-35% crystallinity) for clarity. This composite approach allows thin walls overall while maintaining strength where needed.
3Shape
If a rigid base structure is used to maintain container shape under vacuum, then the container cannot effectively absorb internal vacuum forces
Solution Approach 1:
The base fold is designed as a dynamic, flexible element rather than a rigid structure. It can deflect and deform under vacuum loads, allowing the container to absorb internal vacuum forces through controlled deformation. The flexible base fold acts as a shock absorber, maintaining overall container shape while accommodating local deformations to relieve vacuum stress.
4Loss of substance
If conventional mold design is used without standing ring formation, then material waste occurs from uncontrolled flash
Solution Approach 1:
The patent extracts and controls the flash material by providing dedicated standing ring slots in the mold. Instead of allowing uncontrolled flash to form, the mold design channels excess material into specific slots that form the standing ring feature. This extraction and control of flash material eliminates waste while maintaining ease of manufacture through integrated mold design.
Data Source
AI summary
A mold for forming a plastic container having an integrally formed standing ring. The mold includes a first mold portion and a second mold portion. The second mold portion is movable relative to the first mold portion. The first mold portion and the second mold portion together define at least in part a mold cavity for molding a plastic container. The first mold portion and the second mold portion together define a standing ring slot for forming a standing ring on a base portion of the plastic container. The standing ring slot is defined at an interface between the first mold portion and the second mold portion.