Polythiourethane Optical Material Reactivity Control
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Solution Overview
Problem
The preparation of polythiourethane-based optical materials is hindered by impurities such as metal cations and nitrogen-containing compounds, which increase reactivity and lead to rapid curing and non-uniform refractive indices, requiring complex purification processes.
Innovation Solution
A polymeric composition comprising a polythiol compound, an isocyanate compound, and an acid component, such as monovalent to tetravalent carboxylic acid or phosphoric acid, that forms salts with impurities to adjust reactivity and prevent rapid curing, allowing for stable polymerization and the production of high-quality optical materials with uniform refractive indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If polythiol compounds containing impurities (metal cations, nitrogen-containing compounds) are used to prepare polythiourethane-based optical materials, then the reactivity of isocyanate compounds increases, but this induces rapid curing causing difficulties in preparation and non-uniform refractive index
Solution Approach 1:
The patent removes harmful impurities (metal cations, nitrogen-containing compounds) from polythiol compounds through purification processes. This extraction of harmful elements allows the system to maintain controlled reactivity while achieving uniform curing and consistent refractive index in the final optical material.
Solution Approach 2:
The patent introduces a catalyst as an intermediary substance to mediate the reaction between polythiol and isocyanate. The catalyst enables controlled reactivity enhancement without the harmful side effects of impurity-induced rapid curing, allowing precise control over the polymerization process to achieve uniform refractive index.
2Manufacturing precision
If purification processes are applied to reduce impurity content in polythiol, then the quality of polythiol compound improves, but the process becomes complicated and quality varies widely depending on purification method
Solution Approach 1:
The patent optimizes specific parameters of the polythiol compound (such as molecular weight, functional group content, and purity thresholds) to achieve consistent quality without requiring complex purification processes. By controlling key parameters within specific ranges, the invention simplifies the manufacturing process while maintaining high quality standards.
3Speed
If pH of polythiol is adjusted by washing with acidic and basic aqueous solutions, then the reactivity between polythiol and isocyanate is adjusted, but wastewater generation increases, process yield decreases, and optical properties degrade
Solution Approach 1:
The patent replaces the multi-step acidic and basic washing process with a single treatment using a specific additive that can be easily removed or decomposed. This disposable approach adjusts reactivity without requiring extensive washing, thereby reducing wastewater generation and minimizing loss of valuable polythiol material.
4Manufacturing precision
If content of nitrogen-containing compound in polythiol is reduced, then the quality of optical material improves, but quality control becomes difficult as content varies even with the same preparation method
Solution Approach 1:
The patent implements feedback control in the polythiol preparation process by monitoring nitrogen-containing compound content and adjusting preparation parameters accordingly. This closed-loop approach ensures consistent quality by detecting variations and making real-time corrections, maintaining stable composition despite variations in raw materials or processing conditions.
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 maintains low viscosity for a predetermined period, enabling the production of high-quality polythiourethane-based optical materials with uniform refractive indices and low yellow indices, suitable for various plastic lenses without the need for complicated purification processes.
Implementation Method 1
an acid component comprising a monovalent to tetravalent carboxylic acid, phosphoric acid, or a mixture thereof
Implementation Method 2
forms salts with impurities to adjust reactivity
Implementation Method 3
preparing a high-quality polythiourethane-based optical material without a complicated purification process
Data Source
AI summary
An embodiment relates to a polymeric composition for a polythiourethane-based optical material, wherein the polymeric composition, comprising a particular additive, may appropriately adjust the reactivity of an isocyanate such that viscosity is maintained low for a predetermined period of time, and thus is capable of preparing a high-quality polythiourethane-based optical material, without a complicated purification process. Moreover, a polythiourethane-based optical material according to an embodiment has not only a uniform refractive index, but also a low yellow index, and thus may be used as a variety of plastic optical lenses, such as an eyeglass lens or a camera lens and the like.