Non-Iridescent Structural Colorant via Asymmetric Multilayer Polymer

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Solution Overview

Problem

Existing structural colorants for paints often exhibit iridescence due to their angle-dependent color change, making them unsuitable for large-scale commercial use in paint systems, as they are either incompatible with liquid paint components or result in reduced efficacy when used within paints.

Innovation Solution

A semi-continuous structural colorant is developed, comprising multiple layers of a first polymer with air gaps or a second polymer interspersed between layers, featuring high rotational symmetry to prevent iridescence by maintaining consistent diffraction and reflectance patterns regardless of positioning, utilizing 3D laser lithography for fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If traditional structural colorants are used to provide vibrant and durable color, then color brightness and durability are improved, but iridescence occurs causing angle-dependent color changes

Engineering Contradiction:

Improvecolor brightnessVSAvoidangle independence

Core Design Contradiction:

Illumination intensityVSEase of operation

Solution Approach 1:

The patent applies asymmetry by intentionally introducing random structural variations within the pigment particles. The multilayer structure contains controlled irregularities in layer thickness, composition distribution, and interface roughness that break the perfect symmetry. This asymmetric design causes light scattering that averages out angle-dependent interference effects, eliminating iridescence while preserving the vibrant structural color through the overall multilayer architecture.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If inorganic pigments are used to improve durability and sunlight resistance, then durability is improved, but tint strength decreases requiring large numbers of particles

Engineering Contradiction:

ImprovedurabilityVSAvoidpigment particle concentration

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent employs composite materials by combining organic and inorganic components within the multilayer pigment structure. The alternating layers utilize materials with complementary properties: organic layers provide high tint strength and vivid color, while inorganic layers contribute durability, sunlight resistance, and structural stability. This composite approach allows the pigment to achieve both high color intensity and excellent durability at lower concentrations.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If organic pigments are used to achieve vivid color and high tint strength, then color vividness is improved, but durability decreases due to chemical degradation

Engineering Contradiction:

Improvecolor vividnessVSAvoidchemical stability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

4Illumination intensity

If structural colorants with ordered structures are used to produce color, then color intensity is improved, but iridescence occurs due to angle-dependent diffraction

Engineering Contradiction:

Improvecolor intensityVSAvoidviewing angle independence

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by creating spatial variations in the multilayer structure at different locations within each pigment particle. Different regions contain varying layer thicknesses, material compositions, and interface characteristics. This local heterogeneity causes light to experience different optical paths and interference conditions throughout the particle, averaging out the angle-dependent effects and producing consistent color appearance from all viewing angles while maintaining high color intensity.

Inventive Principle:

Principle #3Local quality

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 structural colorant achieves non-iridescent, durable, and vibrant color effects suitable for paints, maintaining consistent appearance across different angles and environmental exposures, overcoming limitations of traditional pigments and prior art structural colorants.

Implementation Method 1

maintaining consistent diffraction and reflectance patterns

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

maintaining consistent diffraction and reflectance patterns

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

structurally-produced colors may be provided which overcome many of the hurdles of typical organic pigments

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS10087339B2Structural colorants that do not exhibit iridescence

Publication Date: 2018.10.02 THE SHERWIN WILLIAMS CO

AI summary

According to some embodiments, a structural colorant is provided including a semi-continuous structure formed by multiple layers of a first polymer. In some embodiments, air gaps are interspersed between the layers of the first polymer. In some embodiments, a second polymer is interspersed between the layers of the first polymer. In some embodiments, the semi-continuous structure has a center and at least two planes of symmetry through its center.