Foamed Sole Components with Supercritical Fluid Cell Expansion
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Solution Overview
Problem
Existing methods using supercritical fluid (SCF) expansion for three-dimensional foaming materials result in varied curing and non-uniform expansion of cells, leading to sole components with inconsistent hardness, density, resilience, and bonding issues, which are undesirable in certain footwear applications.
Innovation Solution
A method involving pre-expanded polymer materials with or without apertures, using SCF expansion followed by compression molding to create a foamed sole component, ensuring uniform expansion and improved bonding with other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional chemical blowing agents are used for foaming, then high gas volume is generated, but environmental harm and safety issues occur
Solution Approach 1:
The patent changes the physical state and parameters of the blowing agent by using supercritical carbon dioxide instead of traditional chemical blowing agents. This parameter change allows CO2 to achieve high gas volume through phase transition while eliminating environmental harm and safety issues associated with chemical agents.
Solution Approach 2:
The patent utilizes the phase transition properties of carbon dioxide, transitioning it from supercritical state to gaseous state during the foaming process. This phase transition generates high gas volume necessary for foam expansion while avoiding the harmful effects of chemical blowing agents.
2Weight of moving object
If SCF expansion is used for three-dimensional foaming, then weight reduction is achieved, but non-uniform cell expansion and inconsistent properties occur
Solution Approach 1:
The patent applies preliminary compression molding to the pre-expanded polymer material before the SCF expansion step. This preliminary action pre-conditions the material structure, ensuring uniform cell expansion during subsequent SCF foaming and achieving consistent hardness, density, and resilience throughout the sole component.
Solution Approach 2:
The patent carefully controls and adjusts the parameters of SCF expansion, including temperature, pressure, and CO2 saturation time. By optimizing these parameters, the patent achieves uniform cell expansion throughout the three-dimensional structure while maintaining weight reduction benefits.
3Productivity
If pre-expanded polymer material is used, then foaming speed is improved, but bonding consistency with other components deteriorates
Solution Approach 1:
The patent applies preliminary compression molding to pre-expanded polymer material before SCF expansion. This preliminary action maintains the speed advantages of pre-expanded material while creating a more consistent structural foundation that improves bonding consistency with other sole components after foaming.
Solution Approach 2:
The patent optimizes the parameters of compression molding and SCF expansion to achieve a balance between foaming speed and bonding quality. By controlling temperature, pressure, and expansion time parameters, the patent maintains high productivity while ensuring consistent bonding properties.
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 achieves uniform cell expansion and enhanced bonding, resulting in a foamed sole with consistent properties and improved performance characteristics.
Implementation Method 1
placing the pre-expanded polymer material into a pressurized chamber, absorbing the supercritical fluid into the pre-expanded polymer material under the pressurized condition, and expanding the pre-expanded polymer material three-dimensionally to a greater size than the pre-expanded polymer material upon release of the pressure
Data Source
AI summary
A sole structure for articles of footwear and a method of manufacturing them comprising at least one polymeric foamed component expanded through supercritical fluid (SCF) expansion of a shaped pre-expanded polymeric material. The polymeric foamed component may include apertures situated and fashioned in the formation of the pre-expanded polymeric material to promote uniform expansion and optimal curing conditions during the SCF expansion process. At least one polymeric foamed component having one set of physical properties that may be bound to or assembled in conjunction with one or more sole components having the same or another set of physical properties.