Recyclable Structurally-Colored Thermoplastics via Optical Element Segregation

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Solution Overview

Problem

Conventional colored articles recycled from thermoplastic materials often retain colorants, which can be environmentally unfriendly and require additional handling and disposal concerns, and existing methods do not effectively address the recyclability of structurally-colored materials that rely on optical elements for color.

Innovation Solution

The development of recyclable structurally-colored articles and components using thermoplastic materials with integrated optical elements that lose their optical effects during recycling, allowing for the creation of recycled thermoplastic compositions with minimal impact on reflectance, transmittance, or color, enabling their reuse without the need for colorant removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If colorants (dyes or pigments) are used to color thermoplastic materials, then the materials can achieve desired color effects, but the recycled materials retain colorants which create environmental concerns and require additional handling and disposal

Engineering Contradiction:
Improvecoloration processVSAvoidenvironmental impact of colorant disposal
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the color function from chemical colorants (dyes/pigments) and transfers it to physical optical elements. These optical elements are separate components that can be removed during recycling, leaving the thermoplastic material free of harmful colorants. The optical elements provide color through structural optical effects rather than chemical absorption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental parameter of color generation from chemical composition (colorants) to physical structure (optical elements). This parameter change allows the color function to be achieved without incorporating persistent chemical substances into the polymer matrix, enabling easier recycling without colorant removal.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If optical elements are integrated into thermoplastic materials to produce structural color, then environmental concerns are reduced, but the recycled materials retain optical effects that may interfere with reuse applications

Engineering Contradiction:
Improveenvironmental impactVSAvoidreusability of recycled material
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent segments the colored article into two distinct parts: the thermoplastic material matrix and the integrated optical elements. During recycling, these segments can be separated through mechanical processes like grinding and sorting, allowing the optical elements to be removed while the thermoplastic material is recycled for reuse without optical interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables the optical elements to be discarded (removed) during the recycling process while recovering the thermoplastic material in a neutral, reusable form. The optical elements can be sorted out based on their density, size, or optical properties, leaving clean recycled plastic that can be repurposed without color or optical constraints.

Inventive Principle:
Principle #34Discarding and recovering

3Adaptability or versatility

If colorants are removed from recycled thermoplastic materials to enable reuse, then the recycled materials become more versatile, but additional handling steps and disposal concerns are created

Engineering Contradiction:
Improvereusability of recycled materialVSAvoidrecycling process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of starting with colored material and removing colorants (subtraction approach), the patent inverts the approach by starting with neutral thermoplastic material and adding separate optical elements (addition approach). This inversion makes the recycling process simpler because the optical elements can be mechanically separated without complex chemical or physical treatment of the polymer matrix.

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

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 enables the recycling of structurally-colored thermoplastic materials into compositions that maintain their suitability for further manufacturing applications, reducing environmental concerns and handling complexities associated with colorant removal, while ensuring the recycled materials do not retain significant optical effects.

Implementation Method 1

structural colors are visible colors produced, at least in part, through optical effects imparted by the optical element

Methodology Applied
Scientific EffectOptical effects: Reflection

Implementation Method 2

the recycled thermoplastic composition can be characterized by one or more of a visible light reflectance or transmittance or color measurement that is within about 10 percent

Methodology Applied
Scientific EffectVisible light reflectance: Reflection

Implementation Method 3

the optical element or fragments thereof that are deteriorated and do not retain the ability to produce the same optical effects as the initial optical elements

Methodology Applied
Scientific EffectOptical effect deterioration: Ablation

Data Source

PatentEP3924409B1Recyclable structurally-colored structures and articles, and methods of recycling structures and articles
Publication Date: 2023.08.23 NIKE INNOVATE CV
  • EP3924409B1 patent drawingFigure 1A~1M
  • EP3924409B1 patent drawingFigure 1N(a)~1N(b)
  • EP3924409B1 patent drawingFigure 1O(a)~1O(b)

AI summary

In one aspect, a method includes forming an article comprising a first composition comprising from about 1 weight percent to about 100 weight percent of a recycled thermoplastic composition that comprises a first thermoplastic material and a plurality of first optical elements or fragments thereof. Other aspects include an article formed by the method, methods of recycling structurally-colored articles, as well as a recyclable structurally-colored component or article.