Resin Composition for Optical Lenses with High Refractive Index
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Solution Overview
Problem
Current optical materials with inorganic compounds containing sulfur or selenium atoms face challenges in achieving high refractive indices and maintaining transparency, as increased viscosity during polymerization processes complicates cast polymerization and can result in deteriorated tonality.
Innovation Solution
A composition for a resin comprising an inorganic compound with a sulfur or selenium atom, a compound represented by specific formulas, and a preliminary polymerization reaction to reduce viscosity, facilitating cast polymerization and improving refractive index and tonality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the amount of inorganic compound having a sulfur atom and/or a selenium atom is increased to realize a high refractive index, then the refractive index is improved, but the viscosity of the composition is significantly increased making cast polymerization difficult
Solution Approach 1:
A compound having one SH group is introduced as an intermediary substance to control the viscosity of the composition. This compound acts as a mediator between the inorganic compound (for high refractive index) and the polymerization process, enabling cast polymerization to proceed smoothly without sacrificing the high refractive index property.
Solution Approach 2:
The viscosity parameter of the composition is controlled by adjusting the amount of the compound having one SH group. By changing this parameter, the composition becomes suitable for cast polymerization while maintaining the high refractive index achieved through the inorganic compound.
2Reliability
If a preliminary polymerization reaction and degassing are performed to guarantee transparency, then the transparency is improved, but the viscosity of the composition is increased
Solution Approach 1:
The compound having one SH group serves as a viscosity control agent that allows the composition to undergo preliminary polymerization and degassing while maintaining manageable viscosity levels, thus preserving both transparency and manufacturability.
3Ease of manufacture
If compounds having one SH group, disulfide bonds, or NH groups are added to prevent viscosity increase, then the ease of manufacture is improved, but the refractive index is limited to about 1.76 at the highest
Solution Approach 1:
The specific parameter of the SH group compound is optimized to achieve the right balance: enough to control viscosity for easy manufacture, but not so much that it limits the refractive index. This precise parameter control allows both high refractive index and ease of manufacture.
Solution Approach 2:
The compound having one SH group is used specifically for viscosity control without interfering with the optical properties. This localized function allows the inorganic compounds to provide high refractive index while the SH group compound manages the rheological 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 solution effectively increases the refractive index to 1.76 or greater and improves the tonality of the optical material, making it suitable for applications like plastic lenses for eyeglasses.
Implementation Method 1
the present inventors found that a compound represented by the following formula (2) decreases the viscosity of a composition for a resin containing an inorganic compound having a sulfur atom and/or a selenium atom to facilitate a cast polymerization operation
Implementation Method 2
in order to guarantee that the obtained optical material is transparent, a preparation process of a composition of the compound needs to include a preliminary polymerization reaction and degassing. However, during the preliminary polymerization reaction and the degassing, the viscosity of the composition is increased.
Data Source
AI summary
According to a preferable embodiment of the present invention, a composition for a resin comprising an inorganic compound having a sulfur atom and/or a selenium atom, an episulfide compound, and a mercaptodisulfide compound can be provided. According to another preferable embodiment of the present invention, a composition for a resin having the viscosity thereof decreased to facilitate a cast polymerization operation and thus to improve the tonality of the obtained optical material can be provided. According to still another preferable embodiment of the present invention, an optical material obtained by curing the above-described composition for a resin and having a high refractive index can be provided.