Foamed Thermoplastic Elastomer via CO2 Phase Transition
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Solution Overview
Problem
Current methods for producing foamed thermoplastic elastomeric materials are often energy-intensive and require expensive, high-pressure equipment, limiting their scalability and efficiency in creating lightweight, sustainable consumer products like athletic equipment and footwear.
Innovation Solution
A multi-step process involving the infusion of carbon dioxide into a solid foamable material, which expands without thermally softening the material, allowing for the creation of lightweight, multi-cellular foamed articles with reduced material costs and increased sustainability, using simpler and less expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to produce foamed thermoplastic elastomeric materials, then the materials can be formed into foamed articles, but the process requires expensive high-pressure equipment and consumes excessive energy
Solution Approach 1:
The patent changes the physical-chemical parameters of the foaming process by using liquid carbon dioxide infused at moderate pressure and temperature, which then undergoes phase transition to gas at near-atmospheric conditions. This eliminates the need for expensive high-pressure equipment while maintaining effective foaming, directly resolving the contradiction between equipment cost and manufacturing efficiency
Solution Approach 2:
The invention exploits the phase transition of carbon dioxide from liquid to gas state. Liquid CO2 is infused into the thermoplastic elastomer at moderate pressure, then during the expansion step, the CO2 undergoes phase transition to gas, creating foam cells. This phase transition mechanism enables foaming without requiring continuous high-pressure conditions, reducing equipment requirements while maintaining productivity
2Use of energy by moving object
If thermal softening methods are used to foam thermoplastic elastomers, then the material can be expanded, but the process consumes excessive energy and may compromise material properties
Solution Approach 1:
The patent replaces the thermal field (heat-based foaming) with a chemical-physical field (CO2 infusion and phase transition). Instead of using heat to soften and expand the material, liquid CO2 is infused into the solid elastomer and then allowed to phase transition to gas, creating foam through pressure differential and gas expansion rather than thermal softening. This substitution dramatically reduces energy consumption while preserving material properties
Solution Approach 2:
Carbon dioxide serves as an intermediary substance that mediates the foaming process. The liquid CO2 is infused into the solid thermoplastic elastomer, acts as a blowing agent during phase transition, and then escapes or remains as gas cells in the foam structure. This intermediary enables foaming without direct thermal contact, reducing energy input and protecting material integrity
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 process results in lightweight, cost-effective, and sustainable foamed articles with a uniform structure, suitable for various consumer products, including athletic equipment and footwear, while reducing material usage and enabling the use of recycled materials.
Implementation Method 1
producing a phase change that expands the infused carbon dioxide, thereby foaming the infused solid foamable material into a foamed material without thermally softening the solid foamable material
Data Source
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 a first pressure and first 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 second temperature and second pressure, and subjecting the article to a third pressure and third 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.