Polyurethane Optical Lens with Integrated UV Absorber

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Optical materials with photochromic performance often lack stability against ultraviolet light wavelengths, leading to a trade-off between photochromic performance and light resistance, and existing solutions complicate the manufacturing process by requiring separate coating layers.

Innovation Solution

A polymerizable composition combining a polyisocyanate, a polyol compound with a number average molecular weight of 100 or more, a difunctional or higher functional active hydrogen compound, a photochromic compound, and an ultraviolet absorber, which allows for the coexistence of these components to enhance light resistance and maintain photochromic performance without the need for a separate coating layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an ultraviolet absorber is added to enhance light resistance, then stability against ultraviolet light is improved, but photochromic performance deteriorates

Engineering Contradiction:

Improvelight resistanceVSAvoidphotochromic performance

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

A polyol compound with a number average molecular weight of 100 or more serves as an intermediary substance that enables both the ultraviolet absorber and photochromic compound to coexist in the polymerizable composition. This specific polyol compound mediates between the conflicting requirements of light resistance and photochromic performance, allowing both additives to function simultaneously without mutual interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent specifies precise parameter ranges for the polyol compound (number average molecular weight of 100 or more) to achieve optimal compatibility between the ultraviolet absorber and photochromic compound. By controlling the molecular weight parameter of the polyol, the system achieves a balance where both additives can coexist at effective concentrations without degrading each other's performance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a coating layer including photochromic compound is formed on the lens surface, then photochromic performance is maintained, but manufacturing process complexity increases

Engineering Contradiction:

Improvephotochromic performanceVSAvoidmanufacturing process

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the photochromic compound and ultraviolet absorber into a single integrated polymerizable composition that is molded directly into the lens. This eliminates the need for separate coating layers and subsequent lamination processes, combining multiple functions (light resistance and photochromic performance) into one unified manufacturing step.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The polymerizable composition serves multiple functions simultaneously: it acts as the base resin, contains the photochromic compound for color change functionality, includes the ultraviolet absorber for light resistance, and utilizes the polyol compound as a compatibility mediator. This multi-functional composition simplifies the overall system by eliminating separate coating layers.

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 solution provides a polyurethane-based optical material with superior light resistance and stable photochromic performance, simplifying the manufacturing process by integrating the ultraviolet absorber and photochromic compound within the material itself.

Implementation Method 1

a photochromic compound (D)

Methodology Applied

Scientific EffectPhotochromism: Photochromism

Implementation Method 2

an ultraviolet absorber (E)

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

a polymerizable composition for an optical material including: a polyisocyanate compound (A); a polyol compound (B) having a number average molecular weight of 100 or more; a difunctional or higher functional active hydrogen compound (C)

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3351574B1Polymerizable composition for optical materials, optical material obtained from said composition, and plastic lens

Publication Date: 2022.12.21 MITSUI CHEMICALS INC

AI summary

A polymerizable composition for an optical material according to the present invention includes a polyisocyanate compound (A), a polyol compound (B) having a number average molecular weight of 100 or more, a difunctional or higher functional active hydrogen compound (C) (but, excluding the compound (B)), a photochromic compound (D), and an ultraviolet absorber (E).