Photochromic Curable Composition for Lens Stability
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Solution Overview
Problem
Photochromic plastic lenses face issues with storage stability, mechanical strength, and cost-effectiveness due to discoloration and unsatisfactory photochromic properties when using existing curable compositions, particularly those containing chromene compounds with specific polymerizable monomers.
Innovation Solution
A photochromic curable composition is developed with a specific ratio of radically polymerizable monomers having an epoxy group, polyfunctional radically polymerizable monomers, di(meth)acrylate monomers, and urethane di(meth)acrylate monomers, along with a photochromic compound, to enhance photochromic properties and mechanical strength while maintaining low refractive index and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photochromic compounds are compounded with plastics to provide photochromic properties, then photochromic function is achieved, but storage stability deteriorates due to discoloration and yellowing over time
Solution Approach 1:
The patent uses a composite material system combining specific polymerizable monomers (acrylates, methacrylates) with photochromic compounds (fulgimide, spirooxazine, or chromene) to create a cured product that maintains both photochromic function and storage stability. The composite formulation includes controlled ratios of monomers and photochromic compounds to prevent discoloration while preserving optical properties.
Solution Approach 2:
The patent optimizes parameters including the ratio of polymerizable monomers to photochromic compounds, molecular weight of monomers, and curing conditions to achieve a balance between photochromic performance and storage stability. By adjusting these parameters, the cured product maintains low initial coloration and resists yellowing over time.
2Reliability
If photochromic compounds are used in plastic lenses, then photochromic properties are achieved, but mechanical strength becomes unsatisfactory
Solution Approach 1:
The patent creates a composite cured product where the polymer matrix (formed from acrylate/methacrylate monomers) provides mechanical strength while the embedded photochromic compounds provide optical functionality. The composite structure ensures both mechanical integrity and photochromic performance.
Solution Approach 2:
The patent distributes photochromic compounds uniformly throughout the polymer matrix at optimized concentrations, ensuring that mechanical properties are not compromised in any local region while maintaining photochromic functionality throughout the entire lens structure.
3Productivity
If existing curable compositions are used for mass production, then productivity is improved, but cost-effectiveness deteriorates due to discoloration issues requiring rework or rejection
Solution Approach 1:
The patent incorporates stabilizing components and optimized formulations in the initial curable composition that prevent discoloration during storage and use. This preliminary protection eliminates the need for post-production rework or rejection of defective lenses, maintaining both productivity and reliability.
Solution Approach 2:
The patent converts the potential harm of photochromic compound degradation into a benefit by selecting specific compound-monomer combinations that are highly stable. The formulation transforms what could be a source of discoloration into a stable, long-lasting photochromic system that maintains performance over time.
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 provides photochromic lenses with improved storage stability, mechanical strength, and photochromic performance, reducing discoloration and yellowing, and enabling mass production at a lower cost with enhanced optical and mechanical properties.
Implementation Method 1
Photochromism is a reversible function that a certain compound changes its color when it is irradiated by sunlight or light including ultraviolet radiation such as light from a mercury lamp and returns to its original color when it is placed in the dark by stopping the irradiation
Implementation Method 2
a photochromic curable composition which comprises: [A] not less than 0.1 part and less than 5.0 parts by mass of a radically polymerizable monomer having an epoxy group
Data Source
AI summary
A photochromic curable composition comprising [A] not less than 0.1 part and less than 5 parts by mass of a specific radically polymerizable monomer having an epoxy group, [B] 1. 0 to 15 parts by mass of a specific polyfunctional radically polymerizable monomer, [C] 1.0 to 30.0 parts by mass of a specific di (meth) acrylate monomer, [D] more than 50.0 parts and not more than 97.9 parts by mass of a (meth)acrylate monomer except the components [A] to [C] and/or a thio (meth) acrylate monomer, and [E] 0.001 to 10 parts by mass of a photochromic compound based on 100 parts by mass of the total of the polymerizable monomers. The photochromic curable composition can provide a photochromic cured product having excellent photochromic properties for a long time and high mechanical strength, and the photochromic cured product can be manufactured from the photochromic curable composition at a low cost.