Polymerizable Composition for Optical Materials Preventing Striae
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Solution Overview
Problem
Optical materials such as plastic lenses often exhibit striae or cloudiness, which negatively impact their performance and yield, despite advancements in polymerizable compositions containing thiourethane resins.
Innovation Solution
A polymerizable composition comprising an alicyclic or aliphatic isocyanate compound, a thiol compound with sulfide or ester bonds, and an imidazole-based curing catalyst, with the imidazole catalyst used in a specific concentration range to inhibit cloudiness and striae formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymerizable composition containing isocyanate compound and thiol compound is used to produce plastic lenses, then the lenses can be manufactured with good impact resistance and optical properties, but striae or cloudiness occurs in the lenses which negatively impacts performance and yield
Solution Approach 1:
The patent applies parameter changes by precisely controlling the catalyst amount within 5-3000 ppm range and using specific molar ratios of isocyanate to thiol compounds (1:0.95-1:1.05). This optimization of chemical parameters prevents striae and cloudiness while maintaining optical quality and impact resistance of the lenses.
Solution Approach 2:
The patent uses composite materials by combining isocyanate compounds with specific thiol compounds (containing sulfide or ester bonds) in a polymerizable composition. This composite approach creates a thiourethane resin that achieves both good impact resistance and optical properties while preventing defects when proper catalyst amounts are used.
2Productivity
If imidazole-based curing catalyst is used to accelerate polymerization, then the manufacturing efficiency is improved, but improper catalyst amount causes striae or cloudiness which decreases product yield
Solution Approach 1:
The patent optimizes the catalyst concentration parameter to 5-3000 ppm, which is sufficient to accelerate polymerization for high productivity while preventing the formation of striae and cloudiness. This precise parameter control resolves the contradiction between manufacturing efficiency and product quality.
Solution Approach 2:
The patent implements feedback control by specifying the catalyst amount within a precise range (5-3000 ppm) based on the reaction system characteristics. This feedback mechanism ensures that the catalyst amount is optimized to achieve both fast polymerization and defect-free optical quality, preventing both insufficient and excessive catalysis.
3Ease of manufacture
If conventional polymerizable compositions are used, then the manufacturing process is simple, but the optical characteristics are compromised due to striae and cloudiness
Solution Approach 1:
The patent maintains process simplicity while improving optical quality by optimizing specific parameters: catalyst amount (5-3000 ppm) and molar ratios of components. These parameter changes enhance manufacturing precision without complicating the overall manufacturing process, achieving both good impact resistance and optical properties.
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 excellent optical characteristics, including refractive index and prevents cloudiness or striae, enhancing the quality and yield of plastic lenses.
Implementation Method 1
an imidazole-based curing catalyst, in which the amount of the imidazole-based curing catalyst (C) is 5 ppm to 3, 000 ppm with respect to the total amount of the isocyanate compound (A) and the thiol compound (B)
Implementation Method 2
when the composition is heated and polymerized in the presence of a curing catalyst such as imidazoles, a resin can be produced
Data Source
AI summary
The polymerizable composition of the present invention contains (A) an alicyclic isocyanate compound (a1) having two or more functional groups and/or an aliphatic isocyanate compound (a2) having two or more functional groups, (B) a thiol compound having one or more sulfide bonds and/or one or more ester bonds and having two or more functional groups, and (C) an imidazole-based curing catalyst, in which the amount of the imidazole-based curing catalyst (C) is 5 ppm to 3,000 ppm with respect to the total amount of the isocyanate compound (A) and the thiol compound (B).