Optical Material Composition for Viscosity and Color Tone Stability
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Solution Overview
Problem
Existing compositions for optical materials face issues with increased viscosity during compounding and imbalance in color tone changes after curing, heating, and light irradiation, which affect the physical and optical properties of plastic lenses.
Innovation Solution
A composition containing an episulfide compound, a polymerization catalyst, and an ester compound with a halogen at the α position, optionally with sulfur and a polythiol compound, is used to stabilize the viscosity and maintain a balanced color tone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an episulfide compound is used to achieve high refractive index and high Abbe number, then optical properties are improved, but viscosity increases during compounding
Solution Approach 1:
A silane compound is introduced as an intermediary component in the composition. The silane compound reacts with the episulfide compound to form a graft polymer, which acts as a viscosity modifier and processing aid. This intermediary reaction product enables the high-refractive-index episulfide compound to be processed at lower viscosities while maintaining the desired optical properties in the final cured lens.
2Ease of operation
If conventional additives are used to suppress viscosity increase, then workability is improved, but color tone stability deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the composition by selecting specific compounds with controlled reactivity. The silane compound is chosen with specific functional groups that react with episulfide at controlled rates, and the thiol compound is selected with specific molecular weight and functionality to achieve the desired balance between viscosity control and color stability. This parameter optimization allows simultaneous achievement of workability and color tone stability.
3Length of moving object
If refractive index is increased to make lens thinner, then lens thickness is reduced, but Abbe number decreases causing increased chromatic aberration
Solution Approach 1:
The invention uses a composite material system consisting of multiple components: episulfide compound (for high refractive index), silane compound (for processing and crosslinking), thiol compound (for oxidation resistance and viscosity control), and cyclic carbonate (for polymerization). This composite composition achieves a synergistic effect where the final cured lens attains both high refractive index (1.60 or higher) and high Abbe number (30 or higher), breaking the conventional trade-off between lens thickness and chromatic aberration.
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 solution effectively suppresses viscosity increase during compounding and maintains a good balance in color tone changes after curing, heating, and light irradiation, enhancing the performance of optical materials.
Implementation Method 1
an episulfide compound (a), a polymerization catalyst (b) and an ester compound having a halogen at the α position (c)
Data Source
AI summary
A composition for an optical material contains (a) an episulfide compound, (b) a polymerization catalyst, and (c) an ester compound having a halogen at the α position. The (c) ester compound having a halogen at the α position is preferably at least one compound selected from the group consisting of dimethyl chloromalonate, diethyl chloromalonate, dimethyl bromomalonate, and diethyl bromomalonate.