ZrO2 Nanoparticle Functionalization for Transparent Epoxy-Acrylic Coatings

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Solution Overview

Problem

Existing hybrid epoxy-acrylic systems fail to successfully disperse zirconium dioxide (ZrO2) nanoparticles, resulting in opaque or gel-like mixtures unsuitable for coatings, particularly for UV-curable applications on plastic ophthalmic lenses, due to compatibility issues between acrylic and epoxy ZrO2 colloids.

Innovation Solution

Functionalizing ZrO2 nanoparticles with acrylic silane and dispersing them in a hybrid epoxy-acrylic monomer solution, creating a stable and transparent composition that can be UV-cured, forming a low-haze coating on polycarbonate lenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acrylic ZrO2 colloid and epoxy ZrO2 colloid are mixed together, then better optical and mechanical coating properties are expected, but the mixture becomes opaque or gels making it unsuitable for coating applications

Engineering Contradiction:
Improvecoating suitabilityVSAvoidmixture transparency
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses silane coupling agents as intermediary substances to functionalize the ZrO2 nanoparticle surfaces. This creates a compatible interface between the inorganic ZrO2 particles and the organic epoxy-acrylic hybrid matrix, preventing aggregation and gelation while maintaining transparency. The silane layer acts as a mediator that enables stable dispersion of ZrO2 in the hybrid system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface chemistry parameters of ZrO2 nanoparticles through silane functionalization, changing their surface energy and chemical composition. This parameter change enables the particles to be compatible with both acrylic and epoxy monomers simultaneously, allowing stable dispersion without opacity or gelation in the hybrid system.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If ZrO2 nanoparticles are dispersed in hybrid epoxy-acrylic monomers, then high refractive index and mechanical properties are achieved, but compatibility issues cause the mixture to become opaque or gel

Engineering Contradiction:
Improveoptical and mechanical propertiesVSAvoidcoating applicability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Silane coupling agents serve as intermediaries that bridge the inorganic ZrO2 nanoparticles and the organic hybrid monomer system. This intermediary layer ensures compatible interaction between the high-refractive-index particles and the epoxy-acrylic matrix, maintaining both optical clarity and mechanical enhancement while enabling practical coating application.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite material system where ZrO2 nanoparticles are surface-modified with silanes and incorporated into an epoxy-acrylic hybrid matrix. This composite structure combines the high refractive index and hardness of ZrO2 with the processability and optical clarity of the hybrid polymer system, achieving both performance and manufacturability.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If conventional ZrO2 colloids are used in epoxy or acrylic monomers, then stable clear fluids are obtained, but mixing both colloids creates opacity and gelation

Engineering Contradiction:
Improvecolloid stabilityVSAvoidhybrid system compatibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent develops a universal ZrO2 colloid formulation using silane functionalization that can be stably dispersed in both acrylic and epoxy monomers individually and in hybrid combinations. This multi-functional approach eliminates the need for separate colloids for different monomer types, enabling versatile application in hybrid epoxy-acrylic systems while maintaining stability and clarity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 produces a translucent, UV-curable composition that results in a clear, low-haze coating on polycarbonate lenses, addressing the compatibility issues and achieving desired optical and mechanical properties.

Implementation Method 1

ZrO2 nanoparticulate functionalized with an acrylic silane

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

UV curable compositions... UV cured... UV curing

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3024889B1Hybrid epoxy-acrylic with zirconium oxide nanocomposite for curable coatings
Publication Date: 2025.01.15 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

A composition comprising: a continuous liquid phase comprising an acrylic monomer and an epoxy monomer; and a dispersed nanoparticulate comprising ZrO2 modified with an acrylic silane; and wherein the composition is transparent to visible light when coated on a lens. In addition, a method comprising the steps of: mixing an acrylic silane and a methanol-based ZrO2 sol to create a methanol-based silane-modified ZrO2 sol; then mixing at least an acrylic monomer, an epoxy monomer, and the methanol-based silane-modified ZrO2 sol to obtain the composition. The composition can be adapted for coating and curing onto another substrate, such as an ophthalmic lens.