Foamed Thermoplastic Elastomer Articles via CO2 Phase Transition
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Solution Overview
Problem
Existing methods for making foamed articles, particularly those using thermoplastic elastomeric materials, often require thermal softening, which can be energy-intensive and costly. Additionally, these methods may not efficiently incorporate decorative elements or achieve the desired density and structural properties in foamed materials.
Innovation Solution
A method for making decorated foamed articles involves infusing carbon dioxide into a solid foamable material, which is then expanded into a foamed material without thermally softening the material. This process creates a multi-cellular foam structure with low density and allows for the incorporation of decorative elements such as printed, embroidered, or embossed designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal softening is used to foam thermoplastic elastomeric material, then the material can be expanded into foamed articles, but the process becomes energy-intensive and costly
Solution Approach 1:
The patent uses carbon dioxide phase transition from supercritical state to gas state to generate foam expansion, replacing thermal softening methods. The CO2 undergoes phase change at lower temperatures, creating bubbles that expand the material into foamed structure without requiring high energy thermal processing
Solution Approach 2:
The patent changes the physical parameters of carbon dioxide from gaseous to supercritical liquid state for infusion, then utilizes its phase transition properties during expansion. This parameter change allows the material to be foamed without thermal softening, reducing energy consumption while maintaining manufacturability
2Ease of manufacture
If conventional foaming methods are used, then foamed articles can be produced, but decorative elements cannot be effectively incorporated
Solution Approach 1:
The patent applies decorative elements to the material surface before the foaming process. By performing this action preliminarily, the decorative patterns are preserved through the low-temperature CO2 foaming process, which does not melt or deform the surface like thermal methods would
Solution Approach 2:
The use of CO2 phase transition instead of thermal softening allows decorative elements to be incorporated because the process occurs at temperatures that do not melt or deform surface decorations, maintaining their integrity while still achieving foam expansion
3Productivity
If thermoplastic polymer is softened and infused with inert gas, then foaming can occur, but the process requires high temperature and pressure control
Solution Approach 1:
The patent eliminates the need for thermal softening by using CO2 supercritical phase transition and subsequent gas phase expansion. The process relies on pressure-controlled phase changes rather than temperature-dependent softening, significantly reducing the temperature requirements while maintaining foaming efficiency
Solution Approach 2:
The patent replaces the thermal-mechanical softening system with a pressure-phase transition system. Instead of heating to soften the material for gas infusion, the method uses CO2 phase transition under pressure control to achieve foam formation, substituting thermal mechanics with phase transition mechanics
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 foamed articles with a uniform multi-cellular structure, reduced material costs due to lower density, and the ability to incorporate decorative elements effectively. The process is energy-efficient and can be adapted for use with conventional materials and manufacturing lines.
Implementation Method 1
expanding the infused carbon dioxide, e.g., by phase transitioning the infused carbon dioxide to carbon dioxide gas, which in turn expands the solid foamable material into a 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 articles, and methods for manufacturing articles of footwear, apparel, and athletic equipment incorporating the articles are provided. One exemplary method for making a foamed article comprises placing an article comprising a foamable material and carbon dioxide in a vessel, the foamable material; 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.