TPEE Midsole Foam Composition for Low-Density High Rebound Cushioning

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Solution Overview

Problem

Existing sports shoe midsole materials struggle to balance lightweight, low permanent compression set value, and high rebound rate, with most materials either being too dense or lacking sufficient shock absorption and cushioning performance.

Innovation Solution

A multi-block copolyester ether thermoplastic elastomer foam is developed, featuring a block structure prepared from an aromatic polyester compound with short-chain and long-chain structures, and a residual functional group, which is produced through depolymerization and polymerization processes, resulting in a closed-cell structure with specific gravity of 0.19 to 0.24, low permanent compression set value, and high rebound rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If EVA foam material is used for shoe midsole, then shock absorption and cushioning performance is improved, but density is high and rebound rate is low

Engineering Contradiction:

Improveshock absorption and cushioning performanceVSAvoiddensity and rebound rate

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent uses TPEE (thermoplastic polyether ester elastomer) as a composite material that combines soft segments providing elasticity with hard segments providing structural support. This composite structure achieves both shock absorption and high rebound rate, overcoming the limitations of EVA foam which lacks the dual-phase structure needed for simultaneous energy absorption and return.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent adjusts the crystallinity of the hard segment and the flexibility/mobility of the soft segment in TPEE to optimize performance. By controlling these parameters, the material achieves a balance between shock absorption (requiring softness) and rebound rate (requiring elasticity), whereas EVA foam cannot simultaneously optimize both parameters.

Inventive Principle:

Principle #35Parameter changes

2Strength

If TPU foam material is used for shoe midsole, then elasticity is improved, but density is high causing heavy weight and insufficient shock absorption

Engineering Contradiction:

ImproveelasticityVSAvoiddensity and shock absorption

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

TPEE is designed as a segmented copolymer with distinct soft and hard phases. The soft segments provide flexibility and energy absorption, while the hard segments provide structural integrity and rebound. This composite architecture gives TPEE lower density and better shock absorption than TPU foam, while maintaining high elasticity.

Inventive Principle:

Principle #40Composite materials

3Strength

If hardness of shoe midsole material is increased to provide support and anti-wear ability, then support performance is improved, but shock absorption and cushioning value becomes unacceptable

Engineering Contradiction:

Improvesupport and anti-wear abilityVSAvoidshock absorption and cushioning value

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The TPEE material exhibits local quality differentiation through its segmented structure: hard segments localized in certain regions provide support and wear resistance, while soft segments in other regions provide shock absorption and cushioning. This spatial differentiation of material properties allows simultaneous achievement of both support and comfort, whereas homogeneous materials like EVA or TPU cannot provide both functions effectively.

Inventive Principle:

Principle #3Local quality

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 multi-block copolyester ether thermoplastic elastomer foam achieves lightweight, low permanent deformation, and high rebound rate, providing excellent elasticity and cushioning performance for sports shoe midsoles.

Implementation Method 1

a block structure prepared from an aromatic polyester compound with short-chain and long-chain structures, and a residual functional group, which is produced through depolymerization and polymerization processes

Methodology Applied

Scientific EffectDepolymerization: Decomposition (biological)

Data Source

PatentUS12534588B2Multi-block copolyester ether thermoplastic elastomer foam, preparation method thereof, and sports shoe midsole made from the same

Publication Date: 2026.01.27 FAR EASTERN NEW CENTURY COPRRATION

AI summary

Disclosed is a multi-block copolyester ether thermoplastic elastomer foam prepared from an aromatic polyester compound and contains a short-chain structure, a long-chain structure and a residual functional group of a chain extender. The short-chain structure has both an aromatic dicarboxylic acid ethylene glycol ester block structure and an aromatic dicarboxylic acid butylene glycol ester block structure. The long-chain structure has a polyether diol block structure. Based on 100 parts by weight of the multi-block copolyester ether thermoplastic elastomer foam, a content of the polyether diol block structure is 45 parts by weight to 65 parts by weight. The multi-block copolyester ether thermoplastic elastomer foam has a melting point not higher than 170° C. and a melt flow index less than 20 g/10 min.