Compression-Molded TPEE Midsole Core for Energy Return and Stability
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Solution Overview
Problem
Existing footwear sole assemblies, particularly midsoles, face challenges in achieving an optimized balance of support, cushioning, and energy efficiency, with materials like EVA providing decent cushioning but being heavy and less energy efficient, while eTPU and PEBA offer good energy return but lack stability and shear force resistance.
Innovation Solution
A compression molded core made from thermoplastic polyester elastomer (TPEE) is used, increasing its density from 0.05 to 0.12 g/cm³ through molding, and protected by a midsole support wall to enhance energy efficiency to at least 95%, while maintaining cushioning and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVA is used as midsole material, then decent cushioning and good stability are provided, but energy efficiency is reduced and weight increases
Solution Approach 1:
The patent uses a composite structure combining TPEE foam core material with other materials in the midsole assembly. The TPEE foam provides superior energy return (95% energy efficiency) while the composite construction allows optimization of both cushioning and energy efficiency properties that single materials cannot achieve alone.
2Use of energy by moving object
If eTPU and PEBA are used as midsole materials, then exceptional cushioning and energy return are provided, but stability and shear force resistance are reduced
Solution Approach 1:
The patent applies local quality by positioning the TPEE foam core in specific regions where energy return is most beneficial, while other portions of the midsole can use materials optimized for stability and shear resistance. This localized application allows different regions to have specialized properties.
3Reliability
If too much cushioning material is used, then adequate cushioning and comfort are provided, but the sole assembly becomes excessively thick and energy return is reduced
Solution Approach 1:
The patent changes the material parameter by using TPEE foam with specific density and elasticity characteristics. This material achieves superior energy return (95%) in a thinner profile compared to traditional EVA, allowing adequate cushioning with reduced thickness. The key is changing from EVA to TPEE foam material.
4Ease of manufacture
If the foam core is left uncovered, then manufacturing is simplified, but the core becomes susceptible to deformation, damage, scuffing or tearing
Solution Approach 1:
The patent applies beforehand cushioning by providing protective coverage over the TPEE foam core during the manufacturing process. The core is covered with protective material or encapsulated within the midsole structure before final assembly, preventing damage during handling and manufacturing while maintaining the energy efficiency benefits.
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 solution significantly improves energy efficiency to 95% by enhancing the core's density and protection, addressing the limitations of traditional midsole materials, while maintaining comfort and durability.
Implementation Method 1
the compression molded core can be formed by compressing a foam material in a mold to increase density of the foam
Implementation Method 2
a compression molded core disposed in the compartment and at least partially shielded from abrasion in the environment of the footwear in use via the midsole support wall
Data Source
AI summary
A footwear construction including a sole assembly, which can include a midsole including a midsole support wall forming a compartment and a compression molded core constructed from thermoplastic polyester elastomer (TPEE) disposed in the compartment and shielded from abrasion in the environment of the footwear in use via the midsole support wall. The core can be formed by compressing a foam core to increase its density, for example, from a first density between 0.05 g/cm3 and 0.08 g/cm3, inclusive, to a second density between about 0.09 g/cm3 and 0.12 g/cm3, inclusive. Such compression molding and the attendant density increase of the TPEE core can increase energy efficiency to at least 95% energy efficiency, when the midsole is installed in footwear. A related method of manufacture is provided.