E-TPO Shoe Sole Segmentation for Weight and Springback

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Solution Overview

Problem

Existing sports shoes with thermoplastic polyurethane soles face challenges in optimizing weight, spring, and damping properties while maintaining manufacturability simplicity.

Innovation Solution

The sole is composed of sections of expanded thermoplastic polyolefin (E-TPO) and other materials like EVA, TPU, TPE, polyamide, and rubber, with E-TPO sections consisting of spherical or ellipsoidal plastic bodies connected through welding or gluing, offering a lighter and more durable option with improved springback properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If expanded thermoplastic polyurethane (E-TPU) is used as sole material, then good spring and damping properties are achieved, but the weight is higher than desired

Engineering Contradiction:
Improveweight of soleVSAvoidspring and damping properties
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The sole is divided into multiple sections with different materials: E-TPO sections (lighter weight) and other material sections (EVA, TPU, rubber, etc. for enhanced spring and damping). This segmentation allows optimization of weight in certain areas while maintaining performance in critical zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses composite construction by combining E-TPO (expanded thermoplastic polyolefin) with other materials such as EVA, TPU, TPE, polyamide, foamed polyurethane, and rubber in different sole sections. This composite approach achieves lighter overall weight while preserving spring and damping properties through strategic material placement.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If the sole is made lighter by using expanded materials, then weight is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveweight of soleVSAvoidmanufacturability
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The sole is segmented into E-TPO sections and other material sections, which can be manufactured separately and then assembled. This modular approach simplifies manufacturing by allowing each section to be optimized independently and joined through standard processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent specifies controlled parameters for E-TPO sections including density (100-250 g/l), plastic body dimensions (0.5-5.0 mm), and weight (5-10 mg per body). These parameter specifications standardize the material properties, making manufacturing and quality control more manageable despite the complexity of expanded materials.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If spherical or ellipsoidal plastic bodies are used in E-TPO sections, then spring properties are improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvespring propertiesVSAvoiddimensional precision of plastic bodies
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent defines specific parameter ranges for plastic bodies: dimensions between 0.5-5.0 mm in three spatial directions and weight between 5-10 mg. These standardized parameters balance spring property optimization with manufacturability, allowing mass production while maintaining functional performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The combination of E-TPO sections with other materials in the sole structure provides complementary properties that compensate for tolerances in the plastic bodies, allowing broader manufacturing tolerances while maintaining overall spring and damping performance.

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 results in a sole that is up to 30% lighter than traditional E-TPU, with comparable springback properties, reduced yellowing, higher resistance to hydrolysis, and simplified manufacturing, enhancing both performance and production efficiency.

Implementation Method 1

The welding process can be carried out in particular by introducing steam into a tool mold at a pressure of between 0.1 and 0.4 MPa (1.0 and 4.0 bar), preferably between 0.1 and 0.2 MPa (1.0 and 2.0 bar) bar.

Methodology Applied
Scientific EffectSteam welding: Welding

Implementation Method 2

the section of the sole consisting of expanded thermoplastic polyolefin (E-TPO) consisting of a large number of (initially, i.e. in Initial state) consists of spherical or ellipsoidal plastic bodies

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3576562B1Shoe, in particular a sports shoe
Publication Date: 2020.12.16 PUMA SE
  • EP3576562B1 patent drawingFigure 1
  • EP3576562B1 patent drawingFigure 2~3

AI summary

The invention relates to a shoe (1), in particular a sports shoe, having a sole (2) and a shoe upper part (3) connected to the sole (2). According to the invention, in order to improve the use properties of the shoe, the sole (2) is made, at least in sections, from an expanded thermoplastic polyolefin (E-TPO).