UV Curable Photochromic Composition Using Isocyanate Linkers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional photochromic compositions face limitations in photochromism and durability due to the need for strong UV radiation, which degrades the photochromic dye, and thermally curable compositions require long processing times, reducing efficiency.

Innovation Solution

A UV curable photochromic composition incorporating an acrylate-based prepolymer with a polyol structure, where an acrylate functional group is introduced using an isocyanate-based compound with two or more isocyanate functional groups as a linker, allowing for curing under mild UV radiation and preventing thermal aging of the photochromic dye.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If strong UV radiation is used to cure photochromic compositions containing acrylate monomers, then curing reaction occurs, but photochromic dye is degraded leading to reduced optical density and durability

Engineering Contradiction:

Improvedurability of photochromic coating filmVSAvoiddegradation of photochromic dye

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the UV radiation intensity parameter from strong to mild conditions by modifying the curing system. This is achieved by using a specific combination of acrylate monomers with photochromic dyes at optimized ratios, allowing curing to proceed at lower UV intensities that do not degrade the photochromic dye, thus maintaining optical density and durability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite photochromic composition containing acrylate monomers, photochromic dyes, and specific additives in optimized proportions. This composite formulation enables the system to cure under mild UV conditions while maintaining film durability, as the components work synergistically to reduce the required curing energy and protect the photochromic dye from degradation

Inventive Principle:

Principle #40Composite materials

2Reliability

If thermally curable urethane-based resin is used to avoid photochromic dye degradation, then durability is improved, but curing time increases significantly

Engineering Contradiction:

Improvedurability of photochromic coating filmVSAvoidcuring time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the thermal curing mechanism with a UV photopolymerization mechanism. By using acrylate monomers that cure via UV-induced free radical polymerization instead of thermal urethane formation, the system achieves rapid curing (reducing time loss) while maintaining film durability through optimized composition that prevents photochromic dye degradation under mild UV conditions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional UV curable compositions are used, then curing reaction occurs, but strong UV radiation is required causing thermal aging of photochromic dye

Engineering Contradiction:

Improvecuring efficiencyVSAvoidthermal aging of photochromic dye

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent changes the UV radiation intensity parameter from strong to mild conditions by modifying the curing system. This is achieved by using a specific combination of acrylate monomers with photochromic dyes at optimized ratios, allowing curing to proceed at lower UV intensities that do not generate excessive heat, thus preventing thermal aging while maintaining curing efficiency

Inventive Principle:

Principle #35Parameter changes

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 efficient curing under milder UV conditions, enhancing the durability of photochromic products and improving processing efficiency by reducing the energy required for curing while maintaining optical density.

Implementation Method 1

acrylate monomers are crosslinked by UV to form a photochromic coating film

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

Photochromic dyes exhibits color change depending on conformational change such as ring closing or opening reaction, which is contained in the compound. Energy source needed for conformational change of the molecules is typically ultraviolet light at a wavelength of 360 to 380 nm

Methodology Applied

Scientific EffectPhotochromism: Photochromism

Data Source

PatentUS8137595B2UV curable photochromic composition and products formed by using the same

Publication Date: 2012.03.20 LG CHEM LTD

AI summary

The present invention relates to a UV curable photochromic composition comprising a photochromic dye and an acrylate-based prepolymer having a polyol structure in which an acrylate-based functional group is introduced by using an iso-cyanate-based compound having two or more isocyanate functional groups as a linker, and to products formed by using the same.