Coating Composition for High-Refractive-Index Lenses

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Solution Overview

Problem

Conventional coating compositions for high-refractive-index plastic lenses suffer from issues such as interference fringes, clouding, insufficient hardness, and poor adhesion due to compatibility problems between organosilicon compounds and high-refractive-index sols like titanium oxide, leading to poor weather resistance and optical performance.

Innovation Solution

A coating composition is developed that combines silica colloidal particles with high-refractive-index particles without aggregation, using silica colloidal particles as a catalyst for hydrolysis of organosilicon compounds, along with modified metal oxide colloidal particles, to achieve improved compatibility and stability, resulting in a cured film with enhanced hardness, transparency, and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high-refractive-index sols like titanium oxide are used to increase refractive index, then refractive index is improved, but compatibility with organosilicon compounds deteriorates causing aggregation, clouding, and insufficient hardness

Engineering Contradiction:
Improverefractive indexVSAvoidcompatibility
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

Silica colloidal particles are introduced as intermediary substances that mediate between organosilicon compounds and high-refractive-index sols. The silica particles catalyze hydrolysis of organosilicon compounds and promote formation of organosilicon oxycarboxylic acid esters, which then interact with high-refractive-index metal oxide colloidal particles to form stable composite colloidal particles, preventing aggregation and maintaining compatibility

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates composite colloidal particles consisting of organosilicon compound hydrolyzates, silica colloidal particles, and high-refractive-index metal oxide colloidal particles. This composite structure combines the benefits of high refractive index with improved compatibility and stability, as the multiple components work synergistically to prevent aggregation while maintaining optical properties

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional coating compositions are used, then application is simple, but the cured film exhibits interference fringes and clouding reducing transparency

Engineering Contradiction:
Improvecoating application simplicityVSAvoidtransparency
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Silica colloidal particles serve as intermediaries that catalyze hydrolysis reactions and facilitate uniform distribution of high-refractive-index particles throughout the coating composition. This prevents localized aggregation that causes clouding and interference fringes, while maintaining the simplicity of the coating application process

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical parameters of the coating composition by introducing silica colloidal particles that catalyze hydrolysis of organosilicon compounds. This chemical transformation enables uniform dispersion and stable interaction between components, eliminating optical defects like clouding and interference fringes without complicating the manufacturing process

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If high-refractive-index particles are added to increase refractive index, then refractive index is improved, but adhesion with anti-reflective coating deteriorates

Engineering Contradiction:
Improverefractive indexVSAvoidadhesion
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

Silica colloidal particles and organosilicon compound hydrolyzates act as intermediary substances that form chemical bonds between the coating matrix and high-refractive-index metal oxide particles. The resulting composite structure provides both high refractive index and strong adhesion to anti-reflective coatings through the chemically bonded network

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The composite colloidal particle structure combines organosilicon compounds, silica, and high-refractive-index metal oxides in a chemically integrated manner. This composite material provides both the high refractive index needed for optical performance and the adhesion strength required for bonding with anti-reflective coatings

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 solution provides a cured film with excellent scratch resistance, transparency, heat resistance, and weather resistance, suitable for high-refractive-index lenses, eliminating interference fringes and clouding, and ensuring strong adhesion with anti-reflective coatings.

Implementation Method 1

using silica colloidal particles as a catalyst for hydrolysis of organosilicon compounds

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

a coating composition comprises a component (M), a component (F), and a component (S)... a cured film with enhanced hardness, transparency, and adhesion

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentUS11634589B2Coating composition and optical member
Publication Date: 2023.04.25 NISSAN CHEM CORP

AI summary

There are provided a coating composition being possible to form a cured film which has excellent transparency and weather resistance, and especially hardness. A coating composition obtained by which a silicon-containing substance as a component (M) and a silica colloidal particle having a primary particle diameter of 2 to 80 nm as a component (S) are mixed, and then the component (M) is hydrolyzed, and the resulting aqueous solution is subsequently mixed with a colloidal particle (C) wherein a component (F) is a modified metal oxide colloidal particle (C) having a primary particle diameter of 2 to 100 nm, which includes a metal oxide colloidal particle (A) having a primary particle diameter of 2 to 60 nm as a core, whose surface is coated with a coating (B) formed of an acidic oxide colloidal particle.