Foamed Thermoplastic Elastomer via CO2 Phase Transition
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Solution Overview
Problem
Current methods for producing foamed thermoplastic elastomeric materials often require extreme temperatures and pressures, making them costly and energy-intensive, and lack flexibility in adapting to various materials and geometries, limiting their application in mass-produced consumer products like athletic equipment and footwear.
Innovation Solution
A method involving the infusion of carbon dioxide into a solid foamable material, which expands without thermally softening the material, creating a multi-cellular foam structure at or near atmospheric pressure and low temperatures, allowing for simpler, less expensive equipment and processes, and enabling adaptation to different materials and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extreme temperatures and pressures are used to produce foamed thermoplastic elastomeric materials, then the foaming process can be achieved, but the cost and energy consumption increase significantly
Solution Approach 1:
The patent utilizes the phase transition of carbon dioxide from liquid to gas as the foaming agent. Liquid CO2 is infused into the thermoplastic elastomeric material, then pressure is reduced to induce phase transition to gas, creating foam cells. This phase transition occurs at or near atmospheric pressure, eliminating the need for extreme temperatures and pressures while achieving effective foaming.
Solution Approach 2:
Carbon dioxide serves as an intermediary substance in the foaming process. It is infused into the material in liquid state, then transitions to gas to create expansion, and finally is removed or retained as bubbles. This intermediary approach allows foaming to occur under mild conditions rather than requiring direct thermal or mechanical energy input to the material itself.
2Reliability
If conventional foaming methods are used, then foamed material can be produced, but the equipment complexity and manufacturing cost increase
Solution Approach 1:
Carbon dioxide acts as an intermediary that simplifies the equipment requirements. Instead of complex heating and pressurization systems needed for conventional foaming, the process uses CO2 infusion followed by pressure reduction, requiring only infusion equipment and a depressurization mechanism, significantly reducing device complexity.
Solution Approach 2:
The patent replaces complex mechanical heating and pressurization systems with a chemical-physical approach using CO2 phase transitions. The foaming is driven by the phase change of the infused gas rather than external thermal or mechanical energy input, substituting complex mechanical systems with a simpler phase transition mechanism.
3Reliability
If conventional foaming methods are used, then foamed material can be produced, but flexibility in adapting to various materials and geometries is limited
Solution Approach 1:
The CO2 infusion method serves multiple functions and is universally applicable to different thermoplastic elastomeric materials and geometries. The liquid CO2 can penetrate various material types and complex shapes through infusion, and the subsequent pressure reduction causes uniform phase transition throughout the material regardless of its initial form, enabling versatile application across different materials and geometries.
Solution Approach 2:
The process controls foaming by changing parameters such as pressure and temperature in a controlled sequence. By adjusting infusion pressure, holding time, and depressurization rate, the method can adapt to different material properties and desired foam characteristics, providing flexibility for various materials and geometries through parameter optimization rather than fixed process conditions.
4Volume of moving object
If thermally softening is used to expand the material, then the solid foamable material can be expanded, but the material properties may be compromised and energy consumption increases
Solution Approach 1:
The patent achieves material expansion through the phase transition of infused carbon dioxide from liquid to gas, not through thermal softening of the material. The CO2 bubbles form and expand within the material matrix during pressure reduction, physically expanding the material while maintaining its original thermal and mechanical properties since the material itself is not heated to softening temperatures.
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 method results in lightweight, cost-effective, and sustainable foamed articles with controlled volume expansion, suitable for a wide range of applications, including athletic equipment and footwear, while maintaining the material's properties and reducing material usage.
Implementation Method 1
maintaining the vessel at infusing conditions comprising an infusing pressure, an infusing temperature, and an infusing time, wherein at the infusing pressure and the infusing temperature, the carbon dioxide is a liquid and the liquid carbon dioxide is soluble in the solid foamable material
Implementation Method 2
holding the article and the liquid carbon dioxide in the vessel for the infusing time sufficient for at least a portion of the liquid carbon dioxide to infuse into the solid foamable material of the article
Implementation Method 3
subjecting the article to expanding conditions comprising an expanding pressure, an expanding temperature, and an expanding time, wherein under the expanding conditions, the carbon dioxide infused in the solid foamable material phase transitions to a gas, thereby expanding the solid foamable material into a foamed material
Implementation Method 4
conducting a stabilizing step on the foamed article or the intermediary foamed article at stabilizing conditions comprising a stabilizing pressure, a stabilizing temperature, and a stabilizing time, wherein under the stabilizing conditions, the carbon dioxide diffuses out of the foamed material of the foamed article or of the intermediary foamed material
Data Source
Figure 1A~1D
Figure 1E~1H
Figure 1I~1M
AI summary
Foamed articles including a foamed thermoplastic elastomeric material, methods of making the foamed articles, and methods for manufacturing articles of footwear, apparel, and athletic equipment incorporating such foamed articles are provided. In one aspect, a method for making a foamed article comprises placing an article comprising a foamable material and carbon dioxide in a vessel, maintaining the vessel at an infusing pressure and infusing temperature at which the carbon dioxide is a liquid and carbon dioxide is soluble in the foamable material, optionally exposing the infused article to a first intermediary holding temperature and first intermediary holding pressure, and subjecting the article to an expanding pressure and expanding temperature at which the infused carbon dioxide phase transitions to a gas, thereby expanding the foamable material into a foamed material and forming the foamed article.