Polyfunctional Sulfur-Containing Epoxy Compound Production Suppressing Yellowing
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Solution Overview
Problem
Conventional methods for producing polyfunctional sulfur-containing epoxy compounds fail to adequately suppress yellowing, resulting in unsatisfactory color tone and reduced transparency of optical materials like eyeglass lenses.
Innovation Solution
A method involving the reaction of a polyfunctional thiol with epihalohydrin in the presence of a reducing agent, followed by a basic compound, to form a polyfunctional sulfur-containing epoxy compound, where the reducing agent is used in specific amounts and the reaction is conducted within a controlled temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional methods are used to produce polyfunctional sulfur-containing epoxy compounds, then production efficiency is maintained, but yellowing occurs and color tone is unsatisfactory
Solution Approach 1:
The patent applies preliminary action by adding a reducing agent before the main epoxy formation reaction to prevent yellowing. The reducing agent is introduced in the initial stage to reduce disulfide bonds that would otherwise form and cause yellowing, thereby preventing the harmful effect before it occurs during the production process
Solution Approach 2:
The reducing agent acts as an intermediary substance that mediates between the thiol groups and prevents the formation of disulfide bonds. This intermediary chemical species facilitates the formation of the desired epoxy compound while suppressing the harmful yellowing side reaction
2Length of moving object
If the refractive index of optical materials is increased, then lens thickness is reduced, but the Abbe number decreases and chromatic aberration increases
Solution Approach 1:
The patent uses composite materials by combining polyfunctional sulfur-containing epoxy compounds with specific refractive indices and Abbe numbers in the optical material composition. This allows the creation of composite optical materials that achieve both high refractive index for thinness and high Abbe number for low chromatic aberration, resolving the trade-off between these two optical properties
3Object-affected harmful factors
If polyfunctional episulfide compounds are used to improve refractive index and Abbe number, then optical properties are enhanced, but yellowing of the compound and subsequent episulfide compound occurs
Solution Approach 1:
The reducing agent is added in advance to prevent yellowing before it affects the optical material's transparency. By acting preliminarily during the compound formation stage, the reducing agent ensures that the final optical material maintains high transparency without yellowing, thus resolving the contradiction between color tone and transparency
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 method effectively suppresses yellowing, improving the transparency of optical materials by producing a polyfunctional sulfur-containing epoxy compound with a satisfactory color tone.
Implementation Method 1
reacting a polyfunctional thiol with an epihalohydrin in the presence of a reducing agent
Data Source
AI summary
The present invention makes it possible to provide a method for producing a polyfunctional sulfur-containing epoxy compound, the method being characterized in that a polyfunctional thiol is reacted with an epihalohydrin in the presence of a reducing agent to form a polyfunctional sulfur-containing halohydrin, which is then reacted with a basic compound. The reducing agent is preferably at least one selected from the group consisting of sodium borohydride, lithium borohydride, lithium aluminum hydride, diisobutylaluminum hydride, and hydrazine.