PTSI-Controlled Xylylene Diisocyanate for Optical Resin Transparency
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Solution Overview
Problem
Resins produced from conventional xylylene diisocyanate compositions suffer from issues with hue and transparency, necessitating improvements for specific applications.
Innovation Solution
Incorporating a xylylene diisocyanate composition with a controlled ratio of 4-methylbenzenesulfonyl isocyanate (PTSI) ranging from 1 to 100 ppm, combined with active hydrogen group-containing components like polythiols, to produce a polymerizable composition that enhances hue and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional xylylene diisocyanate composition is used, then the resin can be produced, but the hue and transparency are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of 4-methylbenzenesulfonyl isocyanate to 100 ppm or less (ideally 1-20 ppm) in the xylylene diisocyanate composition. This quantitative parameter control directly improves the hue (yellow index ≤ 1.05) and transparency of the resulting resin, resolving the contradiction between manufacturing precision and ease of manufacture by establishing clear compositional specifications.
Solution Approach 2:
The patent applies local quality by focusing control on a specific component (4-methylbenzenesulfonyl isocyanate) within the broader xylylene diisocyanate composition. Rather than controlling all components uniformly, the invention targets the local quality of this particular impurity to achieve the desired optical properties, thereby improving hue and transparency while maintaining manageable manufacturing complexity.
2Reliability
If 4-methylbenzenesulfonyl isocyanate content is increased, then stability against unfavourable colouration improves, but hue and transparency deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal parameter range for 4-methylbenzenesulfonyl isocyanate content (100 ppm or less, preferably 1-20 ppm). This precise parameter control balances the competing requirements: maintaining sufficient stability against unfavourable colouration while ensuring excellent hue (yellow index ≤ 1.05) and transparency for optical applications.
Solution Approach 2:
The patent applies partial action by using a minimal amount of 4-methylbenzenesulfonyl isocyanate (trace levels of 1-20 ppm) rather than larger quantities. This partial presence provides sufficient stabilizing effect against unfavourable colouration while avoiding the excessive concentration that would deteriorate hue and transparency, thus resolving the technical contradiction.
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 resulting resin, molded articles, optical elements, and lenses exhibit excellent hue and transparency, suitable for optical applications.
Implementation Method 1
a xylylene diisocyanate composition has been proposed in which a xylylene diisocyanate and an acyl isocyanate are contained, where the acyl isocyanate is a stabilizer against unfavourable colouration
Implementation Method 2
a polymerizable composition containing any one of the xylylene diisocyanate compositions and an active hydrogen group-containing component
Data Source
AI summary
A xylylene diisocyanate composition includes a xylylene diisocyanate and a 4-methylbenzenesulfonyl isocyanate.