Optical Material Composition Suppressing Polymerization Striae
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Solution Overview
Problem
Conventional polyurethane-based resin compositions for optical materials often exhibit polymerization unevenness, specifically striae, particularly in high-powered lenses with sharp curves, which are difficult to suppress effectively.
Innovation Solution
A composition comprising a polymerization catalyst with a mass ratio of dibutyltin dichloride to monobutyltin trichloride of 99.0/1.0 to 100.0/0.0, a specific polythiol compound, and a polyiso(thio)cyanate compound, along with an acid phosphate ester, is used, where the polythiol compound and polyiso(thio)cyanate are in a specific ratio of SH group to NCO(NCS) group, and the mixture is subjected to annealing after polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyurethane-based resin composition is used for optical materials, then transparency, impact resistance, and stainability are improved, but polymerization unevenness called striae occurs, particularly in high-powered lenses with sharp curves
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of catalyst components (dibutyltin dichloride and monobutyltin trichloride in a mass ratio of 95:5 to 99:1) and polymer components (polythiol and polyiso(thio)cyanate in a NCO(NCS):SH group ratio of 0.95:1 to 1.05:1). It also controls the acid phosphate ester content at 0.01-5 mass% relative to the polythiol compound. These precise parameter adjustments optimize polymerization uniformity while maintaining optical properties, effectively suppressing striae formation in high-powered lenses.
2Reliability
If high-powered lenses with sharp curves are manufactured, then optical performance is improved, but striae formation is significantly increased
Solution Approach 1:
The patent uses parameter changes by optimizing the catalyst system composition (dibutyltin dichloride and monobutyltin trichloride in a mass ratio of 95:5 to 99:1) and the polymer component ratio (NCO(NCS):SH group ratio of 0.95:1 to 1.05:1). This precise parameter control ensures uniform polymerization even in high-powered lenses with sharp curves, suppressing striae formation while maintaining optical performance.
Solution Approach 2:
The patent introduces an acid phosphate ester as an intermediary substance at a controlled content of 0.01-5 mass% relative to the polythiol compound. This intermediary component mediates the polymerization process, promoting uniform reaction progression and reducing polymerization unevenness in high-powered lenses with sharp curves, thereby suppressing striae while maintaining optical quality.
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
This approach effectively suppresses the occurrence of striae in high-powered lenses, improving the optical material's performance by enhancing its refractive index, heat resistance, and impact resistance while maintaining transparency and colorlessness.
Implementation Method 1
a polymerization catalyst having a mass ratio (Bu2SnCl2/BuSnCl3) of dibutyltin dichloride (Bu2SnCl2) to monobutyltin trichloride (BuSnCl3) of 99.0/1.0 to 100.0/0.0 and containing dibutyltin dichloride by 99.0 mass% or more but 99.99 mass% or less and monobutyltin trichloride by 0.01 mass% or more but 1.0 mass% or less
Implementation Method 2
an acid phosphate ester
Data Source
AI summary
The present invention relates to a composition for an optical material, which is capable of suppressing occurrence of polymerization unevenness called striae, in particular, striae to be caused in high-powered lenses with sharp curves, and more specifically relates to a composition for an optical material including: a polymerization catalyst having a mass ratio of dibutyltin dichloride to monobutyltin trichloride of 97.0/3.0 to 100.0/0.0; a polythiol compound; and a polyiso(thio)cyanate compound.