Photochromic Layer Solubility via High MW Acyclic Methacrylate

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Solution Overview

Problem

Existing optical articles with photochromic properties lack high coloring density and weather resistance, and photochromic compounds have poor solubility in polymerizable compositions.

Innovation Solution

A polymerizable composition for optical articles containing ≥ 50.0 mass% acyclic methacrylate with a molecular weight of ≥ 500 and bifunctional (meth)acrylate, either alicyclic or containing branch structures, along with a photochromic compound, to form a photochromic layer with high coloring density and excellent weather resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a photochromic compound is incorporated into a polymerizable composition to form a photochromic layer, then photochromic properties are achieved, but coloring density and weather resistance are insufficient

Engineering Contradiction:

Improveweather resistanceVSAvoidsolubility of photochromic compound

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the molecular weight parameter of the acyclic methacrylate component to ≥500, which fundamentally alters the solubility characteristics and polymerization behavior of the composition. This parameter change enables the photochromic compound to achieve excellent solubility while simultaneously providing high coloring density and weather resistance in the cured photochromic layer.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymerizable composition system combining three key components: acyclic methacrylate (≥500 molecular weight), bifunctional (meth)acrylate, and photochromic compound. This composite approach allows each component to contribute its specific properties - the acyclic methacrylate provides solubility and flexibility, the bifunctional (meth)acrylate contributes to crosslinking and weather resistance, and the photochromic compound delivers coloring functionality with high density.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If conventional polymerizable compositions are used to form photochromic layers, then photochromic properties are achieved, but coloring density remains low

Engineering Contradiction:

Improvecoloring densityVSAvoidweather resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent modifies the molecular weight parameter of the acyclic methacrylate to ≥500, which enables higher loading of photochromic compound (0.1-15 mass%) while maintaining excellent solubility. This parameter change directly increases the quantity of photochromic substance that can be incorporated, achieving high coloring density without compromising weather resistance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent optimizes the local composition within the photochromic layer by specifying precise content ranges: acyclic methacrylate (≥50.0 mass% of total (meth)acrylates) and bifunctional (meth)acrylate (5.0-50.0 mass% of total (meth)acrylates). This local quality control ensures uniform distribution of photochromic compound and optimal polymerization, resulting in both high coloring density and weather resistance throughout the layer.

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If photochromic compound solubility is improved in polymerizable composition, then homogeneous distribution is achieved, but weather resistance may be compromised

Engineering Contradiction:

Improvesolubility and homogeneityVSAvoidweather resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the molecular weight of the acyclic methacrylate to ≥500, which fundamentally improves the solubility of the photochromic compound in the polymerizable composition. This parameter change enables homogeneous mixing and distribution of the photochromic compound without forming aggregates, while the resulting cured layer maintains excellent weather resistance due to the specific polymer network structure formed by the high molecular weight acyclic methacrylate and bifunctional (meth)acrylate combination.

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 composition enables a photochromic layer with high coloring density and excellent weather resistance, and the photochromic compound exhibits excellent solubility, suitable for forming optical articles like spectacle lenses.

Implementation Method 1

A photochromic compound is a compound having a property of developing a color under emission of light in a wavelength range having photoresponsivity and fading without light emission (photochromic properties)

Methodology Applied

Scientific EffectPhotochromism: Photochromism

Implementation Method 2

a method in which a coating is provided on a substrate using a polymerizable composition containing a photochromic compound and a polymerizable compound, and the coating is cured to form a cured layer (photochromic layer) having photochromic properties

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4130855B1Polymerizable composition for optical article, optical article, and eyeglasses

Publication Date: 2026.01.28 HOYA LENS THAILAND LTD

AI summary

Provided is a polymerizable composition for an optical article including a photochromic compound, an acyclic methacrylate having a molecular weight of 500 or more (a component A), and a bifunctional (meth)acrylate containing a structure selected from the group consisting of a cyclic structure and a branch structure (component B).