Thermoplastic Elastomer Shoe Member for High Friction and Low Weight

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Solution Overview

Problem

Conventional shoe members using rubber as the main component face a trade-off in achieving both high static and dynamic friction properties due to the limitations of filler addition, which increases specific gravity and hysteresis loss, making it difficult to improve both properties simultaneously.

Innovation Solution

A shoe member composed of a thermoplastic elastomer with specific glass transition temperature (Tg) and loss tangent (tan δ) properties, including a viscous liquid, to enhance both static and dynamic friction without fillers, maintaining a lightweight design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the amount of filler mixed in rubber is increased to improve static friction properties, then the coefficient of static friction is increased, but the specific gravity of the material increases

Engineering Contradiction:

Improvecoefficient of static frictionVSAvoidspecific gravity

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The invention changes the fundamental material parameter from conventional rubber to thermoplastic elastomer, which has different viscoelastic properties. This material substitution allows achieving high friction coefficients without relying on filler loading, thus avoiding the weight penalty associated with increased filler content in traditional rubber compounds.

Inventive Principle:

Principle #35Parameter changes

2Force

If the amount of filler mixed in rubber is increased to improve static friction properties, then the coefficient of static friction is increased, but the manufacturing cost and complexity increase

Engineering Contradiction:

Improvecoefficient of static frictionVSAvoidfiller mixing and dispersion control

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the filler component from the rubber compound formulation. By using thermoplastic elastomer as the base material, the patent removes the need for filler mixing and dispersion processes, thereby simplifying the manufacturing process and reducing process complexity while maintaining friction performance.

Inventive Principle:

Principle #2Taking out (Extraction)

3Force

If the amount of filler mixed in rubber is increased to improve dynamic friction properties, then the coefficient of dynamic friction is increased to some extent, but the rate of increase is reduced and limits are reached

Engineering Contradiction:

Improvecoefficient of dynamic frictionVSAvoidimprovement rate of friction properties

Core Design Contradiction:

ForceVSProductivity

Solution Approach 1:

The invention changes the material parameter from filler-reliant rubber to thermoplastic elastomer with inherently superior viscoelastic properties. This parameter change enables continued improvement of dynamic friction coefficients without hitting the diminishing returns plateau that occurs in filler-loaded rubber systems.

Inventive Principle:

Principle #35Parameter changes

4Strength

If filler is mixed in rubber to obtain required mechanical properties, then tensile strength and wear resistance are improved, but the specific gravity increases

Engineering Contradiction:

Improvetensile strength and wear resistanceVSAvoidspecific gravity

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The invention uses thermoplastic elastomer as a composite material that inherently provides both mechanical strength and lightweight properties. This composite material approach eliminates the need to add filler for reinforcement, as the thermoplastic elastomer itself offers the required tensile strength and wear resistance without the weight penalty of filler loading.

Inventive Principle:

Principle #40Composite materials

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 provides a shoe member with high coefficients of static and dynamic friction, achieving a specific gravity of less than 1.0, thereby improving performance in climbing and running shoes.

Implementation Method 1

a glass transition temperature Tg of no more than 10° C.

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

a loss tangent tan δ of no less than 0.4 in a test of dynamic viscoelasticity

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 3

hysteresis loss (Δ tan δ) generated due to deformation of the material is increased

Methodology Applied

Scientific EffectHysteresis: Hysteresis

Data Source

PatentUS12569028B2Shoe member and shoe

Publication Date: 2026.03.10 ASICS CORP

AI summary

A shoe member consisting of a material comprising a thermoplastic elastomer, wherein the material has a glass transition temperature Tg of no more than 10° C., a loss tangent tan δ of no less than 0.4 in a test of dynamic viscoelasticity, and a Δ tan δ, which is the amount of change of tan δ, of no less than 0.15 when strain is changed from 5% to 100%.