Shoe Recycling via Density-Selective Extrusion

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Solution Overview

Problem

Recycling of conventional shoes is complex and costly due to the presence of multiple materials with varying densities, making it difficult to produce high-quality recycled materials suitable for new shoe manufacturing.

Innovation Solution

A method involving milling, mixing, heating, and extruding shoe components made from the same material class with varying densities, optionally adding new materials, to produce a melt that can be extruded into high-quality recycled materials for new shoe production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional shoes with multiple different materials are used, then the shoe can achieve various functional requirements (cushioning, support, stability), but the recycling process becomes complicated and expensive

Engineering Contradiction:

Improvefunctional requirementsVSAvoidrecycling process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies homogeneity by using a single material type (thermoplastic polymer) for all shoe components instead of multiple different materials. This allows the entire shoe to be recycled through a uniform process (milling, mixing, extruding) without needing to handle and separate different material types, thereby simplifying the recycling process while maintaining functional requirements through variations in density and composition within the same material class

Inventive Principle:

Principle #33Homogeneity

2Device complexity

If a shoe is made from mostly one material class, then the recycling process is simplified, but producing high-quality recycled material suitable for new shoe manufacturing becomes difficult

Engineering Contradiction:

Improverecycling process complexityVSAvoidrecycled material quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the density and composition parameters of the thermoplastic polymer particles during the recycling process. By adjusting these parameters and using selective extrusion, the process produces recycled material with consistent quality and properties suitable for new shoe manufacturing, overcoming the limitations of single-material recycling

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining thermoplastic polymer particles with different densities and properties within the same material class. This composite approach allows the recycled material to achieve the necessary quality and functional properties for new shoe manufacturing while maintaining a simplified single-material recycling process

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If multiple different material densities are recycled together, then the recycling process can handle varied material properties, but the result cannot be used for new shoes with stringent material quality requirements

Engineering Contradiction:

Improvematerial property variationVSAvoidrecycled material quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by separating and selectively processing particles of different densities during the recycling process. The extrusion device can selectively extrude particles with specific density ranges, allowing the production of high-quality recycled material suitable for new shoes while still handling and processing varied material properties from the original shoe components

Inventive Principle:

Principle #1Segmentation

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 enables the efficient recycling of shoe materials, producing high-quality recycled products that can be used to manufacture new shoes, thereby reducing waste and conserving resources.

Implementation Method 1

applying heat to the mixed particles to obtain a melt of molten particles

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

extruding the melt

Methodology Applied

Scientific EffectExtrusion: Extrusion

Data Source

PatentUS20250162203A1Recycling of a Shoe

Publication Date: 2025.05.22 ADIDAS AG

AI summary

The present invention provides a method for recycling a shoe (100), the shoe (100) comprising various components made from the same material class with varying densities, the method comprises milling (210) the shoe (100) to obtain a plurality of particles (212), the particles (212) having different material densities, mixing (240) the particles, applying heat (312) to the mixed particles (242) to obtain a melt of molten particles and extruding (317) the melt.