Thermoplastic Elastomer Foaming via Supercritical Fluid Infusion
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Solution Overview
Problem
There is a need for improved methods of forming foams that can be customized for cushioning in applications such as footwear and protective wear, as existing methods do not adequately address the requirement for tailored cushioning properties.
Innovation Solution
A method involving infusing a thermoplastic elastomer with a supercritical fluid in a pressurized container, followed by rapid depressurization and heating to foam the article, which can then be annealed to maintain shape and achieve increased modulus, allowing for the production of foamed articles with customized properties such as pellets, beads, or films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thermoplastic elastomers are foamed using conventional chemical or physical blowing agents during polymerization, then foam formation is achieved, but the ability to customize cushioning properties is limited and the process complexity increases
Solution Approach 1:
The patent changes the physical state and pressure parameters of the blowing agent by using supercritical fluids. By controlling pressure and temperature parameters, the same material can be transformed into different foam densities and cushioning properties, enabling customization without complex chemical formulations or multi-step processes
Solution Approach 2:
The patent extracts the foaming step from the polymerization process. Instead of forming foam during polymerization through complex chemical reactions, the invention uses a separate post-polymerization step with supercritical fluids, simplifying the overall process while enabling better control over foam properties for customized cushioning applications
2Manufacturing precision
If thermoplastic elastomer articles with thin dimensions are foamed, then cushioning elements can be produced, but controlling foam uniformity and maintaining shape stability becomes difficult
Solution Approach 1:
The patent utilizes phase transitions of supercritical fluids. By controlling the phase transition from supercritical to gaseous state through pressure release, uniform nucleation and bubble formation occur throughout the thin article, ensuring foam uniformity. The controlled phase transition also allows the foam to maintain shape stability during expansion
Solution Approach 2:
The patent applies preliminary action by infusing the supercritical fluid into the thermoplastic elastomer before foaming. This pre-infusion ensures uniform distribution of the blowing agent throughout the material, particularly important for thin articles, which then enables uniform foam formation and maintains shape stability during the expansion process
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 enables the creation of foamed articles with controlled density and cushioning properties, suitable for applications in footwear and protective gear, by optimizing the absorption of supercritical fluids and subsequent heating processes, resulting in stable and effective cushioning elements.
Implementation Method 1
an article of a thermoplastic elastomer is infused with a supercritical fluid in a pressurized container, then rapidly depressurized and heated
Implementation Method 2
rapidly depressurized and heated either by immersion in a heated fluid that can rapidly heat the article
Implementation Method 3
heated either by immersion in a heated fluid that can rapidly heat the article or with infrared or microwave radiation to heat and foam the article
Implementation Method 4
heated either by immersion in a heated fluid that can rapidly heat the article or with infrared or microwave radiation
Implementation Method 5
heated either by immersion in a heated fluid that can rapidly heat the article or with infrared or microwave radiation
Implementation Method 6
to heat and foam the article. The foamed article may then be used to make a molded product
Implementation Method 7
The foamed article may then be used to make a molded product
Data Source
AI summary
A foamed article is made by infusing the article of thermoplastic elastomer with a supercritical fluid, then removing the article from the supercritical fluid and either (i) immersing the article in a heated fluid or (ii) irradiating the article with infrared or microwave radiation.