Polythiol Composition for Optical Lens Transmittance and Uniformity
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Solution Overview
Problem
Existing polythiol compounds used in manufacturing polyurethane resins for optical lenses face challenges in controlling reaction rates and optical properties, leading to issues such as inhomogeneity, coloration, and reduced transmittance.
Innovation Solution
A polythiol composition comprising at least two different tetrafunctional polythiol compounds, including a main polythiol compound and a sub-polythiol compound, with controlled peak areas and reaction rates to regulate polymerization, thereby improving optical properties and reducing coloration and stria phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polythiol compound is used as a raw material for manufacturing optical lenses, then the optical properties such as transparency and refractive index can be controlled, but the reaction rate variability leads to defects like coloration and stria formation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight distribution and compositional parameters of the polythiol compound. Specifically, it regulates the number-average molecular weight ( Mn) to 1,000-5,000 and controls the ratio of specific polythiol components to achieve optimal reaction rate and uniformity, thereby preventing coloration and stria while maintaining optical quality
Solution Approach 2:
The patent uses composite materials by formulating a polythiol composition containing multiple polythiol compounds with different molecular weights and functional groups. This composite approach allows balancing reaction rate and uniformity, as the mixture of different polythiol species provides both reactivity control and homogeneous polymerization, preventing optical defects
2Productivity
If the reaction rate with isocyanate-based compound is increased to improve productivity, then lens manufacturing efficiency increases, but excessive reaction rate causes coloration and stria defects
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight and functional group composition of the polythiol compound to achieve an ideal reaction rate with isocyanate-based compounds. By controlling Mn to 1,000-5,000 and regulating the composition ratio, the reaction proceeds at an appropriate speed that ensures both productivity and optical quality without causing coloration or stria
Solution Approach 2:
The patent applies local quality by creating a polythiol composition with specific local compositional characteristics - containing particular polythiol compounds in controlled amounts (e.g., 10-50 wt% of specific components). This localized compositional control ensures uniform reaction behavior throughout the material, preventing defects while maintaining efficient reaction rate
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 composition achieves uniform optical properties, inhibits coloration and stria, and enhances transmittance in optical products like lenses by maintaining a balanced reaction rate, ensuring high reliability and chemical stability.
Implementation Method 1
a polythiourethane-based compound prepared by reacting a polythiol compound and an isocyanate compound
Implementation Method 2
a peak area (%) of the polythiol compound represented by C8H18S6, which is measured through a high performance liquid chromatographic (HPLC) analysis graph
Data Source
AI summary
A polythiol composition according to exemplary embodiments includes at least two different polythiol-based compounds, wherein a peak area (%) of the polythiol compound represented by C8H18S6, which is measured through a high performance liquid chromatographic (HPLC) analysis graph obtained at a wavelength of 230 nm, ranges from 0.90% to 1.30%. By controlling the sub-polythiol compound, an optical product having excellent transmittance and optical properties can be manufactured.