Semiconducting Nanoparticle Curing for Thick Thermoset Resins

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Solution Overview

Problem

Radiation curing of thermoset resins is limited by brittleness and restricted to low thickness and transparent formulations, with existing photo-curing mechanisms being wavelength-specific and inefficient for deep polymer layers.

Innovation Solution

Incorporation of inorganic fullerene-like semiconducting nanoparticles, such as WS2 or MoS2, as photo-initiators in radical curable compositions, which absorb a broad spectrum of UV/near-visible light to generate reactive radicals for curing, enhancing the curing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional photo-curing mechanisms are used, then wavelength-specific curing is achieved, but deep polymer layers cannot be effectively cured

Engineering Contradiction:

Improvecuring depthVSAvoidwavelength range

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs a composite photo-initiator system combining organic photoinitiators with inorganic semiconductor nanoparticles (WS2, MoS2, TiO2). This composite approach leverages the broad light absorption capability of inorganic semiconductors across UV-visible range combined with the radical generation efficiency of organic photoinitiators, enabling effective curing of deep polymer layers while maintaining versatility across different wavelength ranges.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The inorganic semiconductor nanoparticles act as intermediaries that absorb photons across a broad spectrum and transfer energy to generate reactive radicals. These nanoparticles mediate between the incident light and the polymer matrix, converting optical energy into chemical reactivity throughout the bulk material, thereby enabling deep penetration and uniform curing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If radiation curing is applied to thick formulations, then complete curing is achieved, but light penetration is blocked

Engineering Contradiction:

Improvepolymer thicknessVSAvoidlight penetration

Core Design Contradiction:

Quantity of substanceVSIllumination intensity

Solution Approach 1:

The patent applies local quality enhancement by incorporating nanoscale semiconductor particles throughout the polymer matrix. These nanoparticles create localized hot spots of radical generation that facilitate curing in deep regions where light intensity is reduced. The high surface area-to-volume ratio of nanoparticles ensures distributed throughout the bulk material, enabling uniform curing even in thick formulations.

Inventive Principle:

Principle #3Local quality

3Productivity

If conventional photo-initiators are used, then surface curing is efficient, but deep layer curing is insufficient

Engineering Contradiction:

Improvecuring efficiencyVSAvoidconversion uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

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 use of semiconducting nanoparticles improves the degree of conversion and mechanical properties of thermoset resins, allowing for thicker coatings and broader wavelength curing, overcoming limitations of traditional photo-curing methods.

Implementation Method 1

Exposure of the NPs to light of appropriate wavelength results in an enabling photovoltaic effect where the absorption of light produces holes and electrons, which are separated by the built-in electric field of the NPs

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

Being a semiconductor, WS2 NPs exhibit high absorbance in UV/near-visible light

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

Hydroxyl radicals (reduction) and H+ ions (oxidation) can be generated at the semiconductor surface in contact with moisture

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 4

Hydroxyl radicals (reduction) and H+ ions (oxidation) can be generated at the semiconductor surface in contact with moisture

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 5

The propagation step is efficient due to a combined effect of the positively charged oxirane ring and thermodynamically driven ring opening

Methodology Applied

Scientific EffectNucleophilic attack:

Implementation Method 6

Cationic curing (CC) of epoxy is accomplished through ring opening mechanism (ROP)

Methodology Applied

Scientific EffectRing opening:

Data Source

PatentUS20250346737A1Radiation induced radical curing by semiconducting nanoparticles

Publication Date: 2025.11.13 YEDA RES & DEV CO LTD

AI summary

This present invention is directed towards radiation-induced radical curing by semiconducting nanoparticles, to thermoset resins and method of preparation thereof. In particular a pure monomeric suspension is utilized without comprising water.