Flexible Container Mold with Collapsible Core and Annealing
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Solution Overview
Problem
Traditional flexible containers with molded and flexible portions face issues such as the flexible portion appearing oversized due to shrinkage differences between molded and flexible materials during injection molding, and difficulties in removing the container from molds due to sticking.
Innovation Solution
A method using an injection mold with a collapsible core to hold the flexible film in place during molding and a post-injection annealing process to shrink the film, ensuring a form-fitted fit with the molded portion and facilitating easy mold removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If flexible film portion is applied during injection molding process, then weight is reduced and labeling is integrated, but flexible portion appears loose or oversized due to shrinkage mismatch
Solution Approach 1:
The patent applies thermal annealing to change the temperature parameter of the flexible container, causing the molded portion to shrink and match the flexible film dimensions. This resolves the shrinkage mismatch issue by using thermal energy to adjust the physical dimensions of the crystalline plastic portion, enabling form-fitting between the flexible film and molded portion.
Solution Approach 2:
The patent applies the flexible film to the molded portion while it is still in the mold during the injection molding process, before the molded portion has fully cooled and shrunk. This preliminary application allows the film to be positioned correctly, and subsequent annealing then coordinates the shrinkage of both the film and molded portion together to achieve form-fitting.
2Ease of manufacture
If aperture is formed in molded portion for flexible film application, then flexible container structure is enabled, but flexible container sticks to mold core and removal becomes difficult
Solution Approach 1:
The patent introduces a collapsible core that can change its volume dynamically - expanded during injection molding to define the aperture space, then collapsed during ejection to reduce friction. This dynamic volume change allows the molded portion to be easily removed from the mold after curing, resolving the sticking problem while maintaining the aperture structure.
3Strength
If traditional molded containers are used, then structural strength is maintained, but weight and production cost increase
Solution Approach 1:
The patent creates a composite structure combining a molded plastic portion (polypropylene or polyethylene) with a flexible film portion (laminate or flexible plastic). This composite construction maintains the structural strength and rigidity needed for container functionality while the flexible film replaces heavy molded sections, achieving weight reduction without sacrificing strength.
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 method results in a flexible container with a snug, form-fitted flexible portion and improved mold removal, reducing weight and production costs while eliminating the need for separate labels and secondary handling processes.
Implementation Method 1
annealing the container to shrink the flexible film so as to provide for form-fitting of the flexible film to the molded portion of the container
Data Source
AI summary
Presented is a method for making a flexible container. The method implements an injection mold having a collapsible core that expands/moves to define the apertures and, in some embodiments, holds a flexible film in place during the injection mold process and collapses/moves back post-injection molding to allow for the flexible container to be readily removed from the die. In addition, the method described includes a post-injection molding anneal process that is implemented to allow the flexible film to shrink so as to provide for the form-fitting of the film to the molded portion of the container.