Isothiocyanate Composition Stabilization for Optical Lens Transparency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Isocyanate compounds used in producing high refractive index plastic lenses are prone to clouding due to their high reactivity with moisture, leading to stability issues even with the use of stabilizers like phenol, especially for highly reactive aromatic ring-containing compounds.
Innovation Solution
A mixture of specific phosphoric acid ester compounds is used as stabilizers in an iso(thio)cyanate composition, with a total amount of 1 ppm to 25,000 ppm based on the mass of the iso(thio)cyanate compound, to enhance storage stability and prevent clouding in the resulting optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phenol is used as a stabilizer for isocyanate compound, then coloration is suppressed and transparency is improved, but clouding still occurs after storage for certain period especially with highly reactive aromatic ring-containing isocyanate compounds
Solution Approach 1:
The patent changes the chemical parameters of the stabilizer from phenol to phosphoric acid ester compounds with specific molecular structures (formulae 1 and 2). This parameter change in the stabilizer's chemical nature provides superior storage stability while maintaining transparency, resolving the contradiction between initial transparency and long-term storage stability.
Solution Approach 2:
The patent uses a composite stabilizer system comprising two different phosphoric acid ester compounds with specific structural features (R1, R3 as C4-C12 alkyl groups; R2, R4 as C1-C4 alkylene groups). This composite approach combines the stabilizing effects of different molecular structures to prevent both clouding and coloration, achieving both transparency and storage stability.
2Illumination intensity
If isocyanate compound with highly reactive aromatic ring is used to achieve high refractive index, then optical performance is improved, but reactivity with moisture increases leading to clouding and reduced storage stability
Solution Approach 1:
The phosphoric acid ester compounds act as intermediary substances that protect the highly reactive aromatic isocyanate compound from moisture. These intermediaries preferentially react with or inhibit the harmful moisture reaction while allowing the isocyanate to maintain its optical properties, thus resolving the contradiction between high refractive index and resistance to clouding.
Solution Approach 2:
The patent converts the high reactivity of the aromatic isocyanate compound, which causes moisture sensitivity, into a benefit by using phosphoric acid ester stabilizers that harness this reactivity to preferentially react with moisture or inhibit its harmful effects, thereby protecting the optical properties while maintaining the high refractive index characteristics.
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 use of phosphoric acid ester compounds effectively stabilizes the iso(thio)cyanate composition, preventing clouding and maintaining transparency in optical components, such as spectacle lenses, for extended storage periods.
Implementation Method 1
an iso(thio)cyanate compound can be stabilized by using a mixture of two predetermined types of phosphoric acid ester compounds as a stabilizer
Data Source
AI summary
An iso(thio)cyanate composition for an optical component has excellent storage stability. The iso(thio)cyanate composition includes an iso(thio)cyanate compound having two or more iso(thio)cyanate groups in a molecule, a phosphoric acid ester compound represented by general formula (1), and a phosphoric acid ester compound represented by general formula (2). A total amount of the phosphoric acid ester compounds is 1 ppm or greater and less than 25,000 ppm, based on the mass of the iso(thio)cyanate compound. A molar ratio of the phosphoric acid ester compound represented by general formula (1) and the phosphoric acid ester compound represented by general formula (2) is 30/70 to 70/30.