Polythiol Composition Reducing Yellow Index in Optical Resins
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Solution Overview
Problem
Resins obtained from polymerizable compositions containing polythiol compounds often exhibit increased yellow index and degree of opacity, making it difficult to achieve reduced yellow index and transparency.
Innovation Solution
A polythiol composition comprising specific polythiol compounds such as 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and a compound represented by Formula (1), with a peak area of 9.0 or less in high performance liquid chromatography measurement, combined with a polyiso(thio)cyanate compound, to produce a resin with reduced yellow index and opacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a polymerizable composition contains a polythiol compound, then the resin can be produced with good heat resistance, but the yellow index and degree of opacity increase
Solution Approach 1:
The patent changes the chemical composition parameters by specifying a polythiol compound with a particular molecular structure (Formula 1 with specific constraints on n, R1-R6 groups) and controlling the peak area ratio (0.01-5.0) through HPLC measurement. This parameter optimization allows the resin to maintain heat resistance while reducing yellowing and opacity
Solution Approach 2:
The patent creates a composite polymerizable composition by combining the specific polythiol compound (Formula 1) with a polyisocyanate compound in controlled ratios. This composite approach enables the resin to achieve both heat resistance and optical clarity by balancing the properties of different materials
2Ease of manufacture
If the polythiol composition contains compounds other than the specified polythiol compound, then the composition is easier to manufacture, but the yellow index and degree of opacity are easily impaired
Solution Approach 1:
The patent establishes precise compositional parameters by specifying that the polythiol compound must have a peak area of 0.01-5.0 (5.0 or less) in HPLC measurement. This quantitative control ensures that even when other compounds are present during manufacturing, the final product maintains low yellow index and opacity while remaining manufacturable
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 proposed polythiol composition effectively reduces the yellow index and degree of opacity of the resulting resin, while maintaining heat resistance and transparency, suitable for optical materials like plastic lenses.
Implementation Method 1
a polymerizable composition, comprising: the polythiol composition according to any one of <1> to <5>, and a polyiso(thio)cyanate compound
Data Source
AI summary
Provided is a polythiol composition including a polythiol compound (A) and a compound represented by the following Formula (1), wherein, in high performance liquid chromatography measurement, a peak area of the compound represented by Formula (1) is 9.0 or less with respect to a total peak area 100 of all compounds contained in the polythiol composition. In Formula (1), X represents a carbon atom or a sulfur atom.