Foamed Thermoplastic Elastomer Articles via Carbon Dioxide 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 production of foamed articles with a multi-cellular structure at relatively low temperatures and pressures, and the option to selectively foam specific regions by controlling carbon dioxide diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extreme temperatures and pressures are used to produce foamed thermoplastic elastomeric materials, then foaming can be achieved, but energy consumption increases and production costs rise
Solution Approach 1:
The patent utilizes the phase transition of carbon dioxide from liquid to gas when depressurized to create foam expansion. The solid foamable material is infused with liquid carbon dioxide at elevated pressure, then upon rapid depressurization, the carbon dioxide phase transitions to gas, causing the material to expand and form a multi-cellular foam structure without requiring extreme temperatures
Solution Approach 2:
The invention employs pneumatic principles by using pressurized carbon dioxide gas to drive the foaming process. The carbon dioxide is introduced at elevated pressure to infuse the solid material, then rapid depressurization causes gas expansion that physically foams the material from within, eliminating the need for thermal softening and extreme temperature conditions
2Manufacturing precision
If conventional foaming methods are used, then uniform foaming can be achieved, but selective foaming of specific regions requires additional tooling and equipment
Solution Approach 1:
The patent enables selective foaming by controlling the local distribution and diffusion of carbon dioxide within the solid foamable material. By adjusting processing parameters such as temperature, pressure, and exposure time, carbon dioxide can be made to diffuse into specific regions of the material, allowing selective foaming of particular areas without requiring additional tooling or equipment
Solution Approach 2:
The invention utilizes parameter changes in temperature and pressure to control carbon dioxide diffusion and foaming behavior. By varying these parameters during the process, selective regions of the solid material can be targeted for foaming while leaving other regions unfoamed, achieving manufacturing precision without increasing device complexity
3Volume of moving object
If thermoplastic elastomeric materials are thermally softened for foaming, then expansion can occur, but material costs increase and sustainability decreases
Solution Approach 1:
The patent replaces the thermal mechanism traditionally used for softening and expanding thermoplastic elastomers with a mechanical/pneumatic mechanism. Carbon dioxide gas expansion physically foams the solid material from within through pressure differential, eliminating the need for thermal softening and reducing material degradation and costs
Solution Approach 2:
The invention employs carbon dioxide, a readily available and inexpensive gas, as the foaming agent. The carbon dioxide is infused into the solid material, provides the necessary expansion force through phase transition, and then dissipates, leaving behind the foamed structure without requiring expensive thermoplastic processing or creating harmful byproducts
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 approach reduces material costs, allows for the use of recycled materials, and creates lightweight, sustainable foamed articles with customizable density and volume expansion, while being energy-efficient and adaptable to various geometries and materials.
Implementation Method 1
infusing carbon dioxide into a solid foamable material, which undergoes a phase change to expand without thermally softening the material
Implementation Method 2
expanding the infused carbon dioxide, e.g., by phase transitioning the infused carbon dioxide to carbon dioxide gas
Implementation Method 3
controlling carbon dioxide diffusion
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.