Foamed Thermoplastic Elastomer Articles 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 energy-intensive and costly, and lack the ability to selectively foam specific regions of articles without additional tooling or equipment.
Innovation Solution
A method involving the infusion of carbon dioxide into a solid foamable material, which undergoes a phase change to expand without thermally softening the material, allowing for the creation of foamed articles with a multi-cellular structure using simpler, less expensive equipment and processes, and enabling selective foaming of specific regions.
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 energy consumption increases and production costs rise
Solution Approach 1:
The patent utilizes the phase transition of carbon dioxide from liquid to gas when exposed to water or moisture. The CO2 is infused into the thermoplastic elastomer in liquid form under pressure, then upon contact with water during the foaming step, it rapidly transitions to gas form, creating cellular structures within the material. This phase transition mechanism eliminates the need for extreme temperatures and pressures traditionally required for foaming, directly resolving the contradiction between achieving reliable foaming and reducing energy consumption
Solution Approach 2:
Water acts as an intermediary substance that triggers the foaming process. Instead of directly applying extreme heat and pressure to the thermoplastic elastomer, the patent uses water as a medium to induce CO2 phase transition, which then drives the foaming. This intermediary approach allows the foaming process to occur under milder conditions, reducing energy consumption while maintaining process reliability
2Manufacturing precision
If traditional foaming methods are used, then uniform foaming can be achieved, but the ability to selectively foam specific regions is lost without additional tooling or equipment
Solution Approach 1:
The patent enables different regions of the thermoplastic elastomer to have different foaming properties by controlling CO2 infusion and water exposure locally. Specific areas can be targeted with water application while other areas remain unaffected, allowing selective foaming of particular regions. This local quality approach achieves manufacturing precision for selective region foaming without requiring complex additional tooling, as the selectivity is achieved through controlled application of the water trigger rather than through complex equipment
3Ease of operation
If thermoplastic elastomeric material is thermally softened for foaming, then the material becomes more pliable for expansion, but the original material structure and properties are altered
Solution Approach 1:
The patent replaces the thermal mechanism (heat-based softening) with a mechanical/physical mechanism (CO2 phase transition and expansion). Instead of using heat to soften the thermoplastic elastomer and enable foaming, the process uses pressurized CO2 infusion followed by phase transition to gas upon water contact. The CO2 gas bubbles form and expand within the material structure, creating foam without requiring thermal softening. This substitution preserves the original material structure and properties while achieving the necessary pliability for expansion through the physical expansion of CO2 bubbles
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 reduces material costs, weight, and environmental impact by creating lightweight, sustainable foamed articles with controlled volume expansion, suitable for various consumer products, including athletic equipment and footwear, while maintaining the structural integrity of the original material.
Implementation Method 1
producing a phase change that expands the solid foamable material into the foamed material without thermally softening the solid foamable material
Implementation Method 2
maintaining the vessel at a first pressure and first temperature at which the carbon dioxide is a liquid and the liquid carbon dioxide is soluble in the solid foamable 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 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.