Recyclable Shoe Last via Phase Transition Plastic

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Solution Overview

Problem

Existing technologies do not provide a method for recycling lasts used in shoe production, leading to waste and inefficiency.

Innovation Solution

A recyclable last made of a plastic material that can transform between a solid state and a plasticized state, allowing it to be reused by dissolving and re-forming using 3D printing technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a last is used for shaping a shoe upper, then the shoe upper can be customized to fit the user's foot, but the last becomes waste and cannot be reused

Engineering Contradiction:

Improvecustomization capabilityVSAvoidlast waste

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The last is made from a material that can change its state between solid and plasticized forms. When heated, the material transitions to a plasticized state allowing the last to be dissolved and reformed into new shapes, enabling reuse for different shoe sizes and styles while maintaining customization capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition of the plastic material between solid and plasticized states through temperature control. This allows the last to be transformed from a rigid functional form to a dissolvable state, then reformed into new lasts, eliminating waste while preserving the adaptability for custom shoe fitting

Inventive Principle:

Principle #36Phase transitions

2Stability of the object's composition

If a last is made of traditional materials, then it provides structural stability during shoe upper shaping, but it cannot be recycled or reused

Engineering Contradiction:

Improvestructural stabilityVSAvoidrecyclability

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The last is constructed from plastic material whose physical parameters can be changed through heating. In the solid state, it provides structural stability for shaping; when heated to the plasticized state, it becomes dissolvable and reformable, enabling recycling without compromising manufacturing ease

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses plastic material that combines the properties of structural integrity in solid form with solubility and reformability in plasticized form. This composite characteristic allows the last to maintain stability during use while enabling easy recycling through dissolution and reformation processes

Inventive Principle:

Principle #40Composite materials

3Loss of time

If lasts are discarded after single use, then production time for new custom lasts is reduced, but material waste increases and sustainability is compromised

Engineering Contradiction:

Improveproduction timeVSAvoidmaterial waste

Core Design Contradiction:

Loss of timeVSLoss of substance

Solution Approach 1:

By utilizing phase transition between solid and plasticized states, the last material can be rapidly transformed and reformed into new lasts. This process significantly reduces the time required to create new custom lasts compared to traditional manufacturing, while simultaneously eliminating material waste through repeated reuse

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

Instead of discarding the last after single use, the patent implements a recovery process where the plastic material is dissolved from the used last and reformed into new lasts. This recovers the material completely, eliminating waste while the efficient reformation process reduces production time for subsequent custom shoe projects

Inventive Principle:

Principle #34Discarding and recovering

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

Enables the efficient recycling of lasts, reducing waste and allowing for the customization and reuse of shoe production tools, while also simplifying the production process.

Implementation Method 1

at least an outer peripheral portion composed of a plastic material that is reversibly transformed between a solid state where the plastic material has a certain shape when the shoe upper is shaped and a plasticized state where the plastic material has fluidity and is thereby deformable

Methodology Applied

Scientific EffectPhase transition: Phase Change

Data Source

PatentEP4209144B1Leisten, verfahren zur herstellung eines leisten und verfahren zur herstellung eines schuhoberteils

Publication Date: 2025.05.07 ASICS CORP

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AI summary

An object of the present invention is to provide a recyclable last, a method for producing the last, and a method for producing a shoe upper. Provided is a last for shaping a shoe upper. The last includes at least an outer peripheral portion composed of a plastic material that is reversibly transformed between a solid state where the plastic material has a certain shape when the shoe upper is shaped, and a plasticized state where the plastic material has fluidity and is thereby deformable.