Isocyanate Composition for Stable, Non-Discoloring Spectacle Lenses
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Solution Overview
Problem
Isocyanates used as raw materials for plastic spectacle lenses have high reactivity and tend to discolor when stored for a long time, making them unsuitable for use in optical materials.
Innovation Solution
An isocyanate composition comprising a compound represented by Formula (1) and an isocyanate component, combined with an active hydrogen compound, to form a polymerizable composition that includes a resin, which is then cured to produce an optical material and spectacle lens, enhancing storage stability without using toxic stabilizers like 2,6-di-tert-butyl-p-cresol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional isocyanates are used for plastic spectacle lenses, then the lenses can be produced with appropriate processability, but the isocyanates discolor when stored for a long time due to high reactivity
Solution Approach 1:
A phenolic antioxidant compound is introduced as an intermediary substance to inhibit the oxidation reaction of isocyanates. The antioxidant acts as a mediator that prevents direct harmful interactions between isocyanates and oxygen, thereby preventing discoloration while maintaining the isocyanates' reactivity for lens production
Solution Approach 2:
The chemical composition parameters of the isocyanate system are changed by adding specific phenolic compounds with hydroxyl groups. This parameter change transforms the system from one that rapidly oxidizes and discolors to one with enhanced storage stability, while preserving the necessary reactivity for polymerization
2Productivity
If high reactivity isocyanates are used to ensure processability, then the lenses can be manufactured efficiently, but the storage life is reduced due to premature reaction
Solution Approach 1:
The phenolic antioxidant provides beforehand cushioning by pre-establishing a protective chemical environment. This cushioning effect suppresses premature polymerization and oxidation reactions during storage, allowing the isocyanates to maintain their reactivity until the actual manufacturing process begins
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 achieves high storage stability, allowing the production of isocyanate compositions, resins, and spectacle lenses with improved longevity and performance.
Implementation Method 1
Isocyanates used as raw materials for plastic spectacle lenses generally have high reactivity, and readily become discolored when stored for a long time
Implementation Method 2
a polymerizable composition including the above isocyanate composition, and an active hydrogen compound component
Data Source
Figure 1
AI summary
There are provided an isocyanate composition including a compound represented by Formula (1) and an isocyanate component, a polymerizable composition including the isocyanate composition, a resin which is a cured product of the polymerizable composition, an optical material including the resin, and a spectacle lens including the resin