Polythiourethane Resin Tintability and Heat Resistance
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Solution Overview
Problem
Conventional resins for spectacle lenses face challenges in achieving a balance between tintability and resin strength, with existing materials often compromising on heat resistance and processing durability.
Innovation Solution
A polymerizable composition containing an alicyclic isocyanate compound, a specific isocyanate compound, a polythiol compound with sulfide bonds, and a polyhydroxy or polyhydroxy-mercapto compound, which are polymerized to produce a polythiourethane resin that enhances tintability and resin strength while maintaining refractive index, Abbe's number, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional resin materials are used to achieve heat resistance, then heat resistance is improved, but tintability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific polythiol compound with sulfide bonds and controlling the ratio of hydroxy groups to thiol groups (100xA/(A+B+C) between 10-40%). This parameter optimization enables the resin to achieve both heat resistance (Tg ≥ 100°C) and excellent tintability without the traditional tradeoff
Solution Approach 2:
The patent creates a composite polymer system combining polythiourethane resin with specific isocyanate compounds and polythiol compounds. This composite material structure integrates the thermal stability from the isocyanate-polyhydroxy backbone with the enhanced tintability and crosslinking from the polythiol-sulfide components
2Strength
If resin strength is improved to endure processing, then processing durability is improved, but yield rate deteriorates due to breakage
Solution Approach 1:
The patent optimizes the molecular structure parameters by incorporating polythiol compounds with specific sulfide bond configurations and controlling functional group ratios. This results in resin strength sufficient for processing while minimizing breakage and improving yield rate
3Ease of manufacture
If tintability is improved by lowering tinting temperature, then ease of tinting is improved, but heat resistance deteriorates
Solution Approach 1:
The patent changes the chemical parameters by introducing polythiol compounds with sulfide bonds that enable effective tinting at lower temperatures while the crosslinked polythiourethane structure maintains high heat resistance (Tg ≥ 100°C), eliminating the need for high-temperature tinting processes
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 resulting polythiourethane resin exhibits excellent tintability, resin strength, and optical properties, including high refractive index and heat resistance, making it suitable for use in optical components such as spectacle lenses.
Implementation Method 1
a polymerizable composition containing (A) an alicyclic isocyanate compound... (C) at least one polythiol compound... (D) at least one polyhydroxy compound... wherein the polymerizable composition is polymerized
Data Source
AI summary
A resin composition excellent in tintability and resin strength, a resin obtained by curing such a resin composition, and an optical component is provided. A polymerizable composition containing an isocyanate compound suitably used for transparent resin materials, at least one polythiol compound which may have one or more (poly)sulfide bonds in a molecule, and at least one polyhydroxy compound having two or more hydroxy groups in a molecule and/or at least one (poly)hydroxy(poly)mercapto compound having one or more hydroxy groups and one or more thiol groups is used.