Aromatic Polythiol Optical Material High Refractive Index
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Solution Overview
Problem
Current polythiourethane-based optical materials lack sufficient refractive index and high sulfur content, limiting their optical and mechanical properties such as low specific gravity and cure shrinkage.
Innovation Solution
Development of bi- or higher-functional aromatic polythiol compounds with a high sulfur content, synthesized through specific reaction processes involving divinylbenzene and aliphatic polythiols, which are then polymerized with isocyanates to produce optical materials with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polythiourethane-based compounds are prepared using conventional polythiol compounds, then the optical materials can be produced, but the refractive index is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the polythiol compound by incorporating aromatic rings and increasing sulfur content to specific ranges (30-70 wt%). This parameter optimization directly improves the refractive index of the resulting polythiourethane optical material while maintaining adequate sulfur content for optical properties.
Solution Approach 2:
The patent creates a composite molecular structure by combining aromatic rings with polythiol groups in a specific configuration. This composite structure at the molecular level enables the material to achieve both high refractive index (optical property) and appropriate sulfur content (chemical composition), resolving the contradiction between these two parameters.
2Temperature
If polythiol compounds with high sulfur content are used, then refractive index improves, but specific gravity increases
Solution Approach 1:
The patent optimizes the sulfur content parameter within a specific range (30-70 wt%) rather than maximizing it. This controlled parameter change achieves sufficient refractive index improvement while preventing excessive specific gravity increase, finding the optimal balance point between these two conflicting properties.
Solution Approach 2:
The patent introduces aromatic rings at specific positions in the molecular structure to locally enhance optical properties (refractive index) without uniformly increasing the overall density. This localized structural modification allows refractive index improvement while controlling specific gravity increase.
3Ease of manufacture
If conventional polythiol compounds are used, then the synthesis process is simple, but cure shrinkage is high
Solution Approach 1:
The patent designs a composite molecular structure combining aromatic rings with polythiol groups in a specific architecture. This composite structure provides both mechanical stability (reducing cure shrinkage) and optical performance, while the synthesis process remains relatively straightforward using conventional polymerization methods.
Solution Approach 2:
The patent pre-designs the molecular structure of the polythiol compound with appropriate aromatic ring configurations before polymerization. This preliminary structural design ensures that the resulting polythiourethane has reduced cure shrinkage, and the synthesis process follows conventional steps without requiring complex additional operations.
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 optical materials exhibit high refractive index, low specific gravity, and low cure shrinkage, making them suitable for applications in plastic optical lenses like eyeglass and camera lenses.
Implementation Method 1
A polythiourethane-based compound may be prepared by reacting a polythiol compound and an isocyanate compound
Data Source
AI summary
An embodiment relates to an aromatic polythiol compound for optical materials, and the aromatic polythiol compound according to the embodiment contains a phenyl group and a large number of sulfur atoms in its polythiol structure so that a polymerizable composition and an optical material obtained therefrom have excellent optical properties such as high refractive index and low specific gravity, as well as excellent mechanical properties such as low cure shrinkage; thus, they can be advantageously used for producing various plastic optical lenses such as eyeglass lenses and camera lenses.