Knitted Shoe Upper With Selective Coating for Stretch Control

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Solution Overview

Problem

Conventional shoe uppers, particularly for sports shoes, are time-consuming to assemble due to multiple parts made from various materials, leading to waste and altering the appearance when methods to reduce stretchability are applied.

Innovation Solution

A shoe upper with a weft-knitted fabric comprising a first layer of yarn and a second layer of monofilament, connected to reduce stretchability, combined with a polymer coating applied under heat and pressure to reinforce and shape the fabric.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If thermoplastic materials are used to stiffen the knitted shoe upper, then stretchability is reduced, but the appearance of the knitted fabric is altered and design options are limited

Engineering Contradiction:
Improvestretchability reductionVSAvoiddesign options
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The shoe upper is divided into multiple zones with different stiffness requirements. Polymer coating is applied selectively only to specific portions (e.g., toe area, heel, midfoot) that require reduced stretchability, while other areas maintain the original knitted fabric properties and design freedom.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the shoe upper are given different properties through selective polymer coating application. The coated areas gain reduced stretchability and increased stability, while uncoated areas retain the elastic and aesthetic properties of the knitted fabric, allowing localized functional optimization without compromising overall design versatility.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If additional structures are applied to reduce stretchability, then stretchability is reduced, but the number of parts increases and manufacturing effort increases

Engineering Contradiction:
Improvestretchability reductionVSAvoidnumber of parts
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The polymer coating process integrates multiple functions into a single operation: it reduces stretchability, provides structural reinforcement, and creates the desired stiffness profile all in one step. This eliminates the need for separate reinforcement components, panels, or additional structural elements that would otherwise need to be manufactured and assembled.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mechanical approach of adding separate reinforcement structures (such as stiffening panels, ribs, or additional layers) is replaced by a chemical/coating approach where polymer material is applied directly to the knitted fabric. This substitution reduces part count and simplifies manufacturing while achieving the same functional effect of reduced stretchability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If structures are applied to the outside of the shoe upper, then stretchability is reduced, but the appearance is altered

Engineering Contradiction:
Improvestretchability reductionVSAvoidappearance
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

Instead of applying stiffening structures to the outside of the shoe upper where they would be visible and alter the appearance, the polymer coating is applied to the inside surface of the knitted fabric. This inverted approach allows the exterior aesthetic properties of the knitted material to remain unchanged while still achieving the desired reduction in stretchability and increase in stability.

Inventive Principle:
Principle #13The other way round (Inversion)

4Stability of the object's composition

If applied structures are used to reduce stretchability, then stretchability is reduced in certain directions, but stretchability is not reduced in all directions

Engineering Contradiction:
Improvestretchability reductionVSAvoidstretchability control
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The stretchability of the knitted fabric is controlled by changing the physical and chemical parameters of the material through polymer coating application. By adjusting polymer material properties (viscosity, hardness, elasticity) and application parameters (thickness, distribution, curing conditions), uniform reduction of stretchability can be achieved in all directions within the coated areas, providing precise control over the mechanical properties.

Inventive Principle:
Principle #35Parameter changes

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 allows for a one-piece manufacturing of shoe uppers with reduced stretchability without affecting the appearance, providing increased stability and design flexibility.

Implementation Method 1

certain portions of which are stiffened by the use of yarns for the textile material which contain synthetic filaments which are heat treated so that the textile material melts and subsequently solidifies

Methodology Applied
Scientific EffectMelting and solidification: Melting

Data Source

PatentEP3398471B1Shoe upper
Publication Date: 2026.04.29 ADIDAS AG
  • EP3398471B1 patent drawingFigure 1~2
  • EP3398471B1 patent drawingFigure 3~4
  • EP3398471B1 patent drawingFigure 5~6

AI summary

A shoe upper (1) for a shoe, in particular a sports shoe (2), having a first portion and a second portion which are jointly manufactured as a knitted fabric (11, 12, 13), wherein the first portion and/or the second portion comprises a first textile layer and a second textile layer, wherein the first textile layer comprises a yarn, and wherein the second textile layer comprises a monofilament.