Dual-Polythiol Composition for Stria-Free Optical Lens Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polythiol compounds used in manufacturing polyurethane resins for optical lenses suffer from issues such as reduced transparency, optical non-uniformity, and varying mechanical and optical properties due to reactivity and molecular weight variations, leading to problems like stria formation and white turbidity.
Innovation Solution
A polythiol composition comprising a first polythiol compound, such as a trifunctional or tetrafunctional compound, combined with a second polythiol compound having a higher molecular weight and functional groups, controlled within specific ppm ranges, to regulate reaction rates and enhance mechanical and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polythiol compound with high reactivity is used to improve reaction rate, then productivity is improved, but manufacturing precision deteriorates due to stria formation and optical non-uniformity
Solution Approach 1:
The patent changes the molecular weight parameter of the polythiol compound from conventional low values to specifically 2,000-10,000 g/mol, and controls the functional group density at 2.0-4.0 mmol/g. This parameter optimization reduces excessive reactivity while maintaining adequate reaction rate, preventing stria formation and improving optical uniformity.
Solution Approach 2:
The patent introduces a dual-component polythiol system where Component A (lower molecular weight, higher functionality) and Component B (higher molecular weight, lower functionality) are combined in specific ratios. This creates local quality differentiation within the material, where each component contributes different properties: Component A provides reactivity while Component B provides uniformity and prevents stria.
2Adaptability or versatility
If polythiol compounds with varying molecular weights and functional groups are used, then adaptability is improved, but reliability deteriorates due to inconsistent optical and mechanical properties
Solution Approach 1:
The patent establishes specific parameter ranges: molecular weight 2,000-10,000 g/mol and functional group density 2.0-4.0 mmol/g. Within these controlled ranges, the polythiol composition achieves consistent optical and mechanical properties while maintaining adaptability for different lens applications.
Solution Approach 2:
The patent creates a composite polythiol system combining Component A and Component B with specific molecular weights and functionalities. This composite approach allows property adjustment through composition ratio while maintaining reliability through the constrained property ranges of individual components.
3Productivity
If excessive reaction rate occurs during polymerization, then productivity is improved, but manufacturing precision deteriorates due to stria formation and white turbidity
Solution Approach 1:
The patent optimizes the polythiol compound parameters (molecular weight 2,000-10,000 g/mol, functional group density 2.0-4.0 mmol/g) to achieve moderate reaction rate. This prevents excessive reaction speed that causes stria and white turbidity, while still maintaining adequate polymerization efficiency for practical production.
Solution Approach 2:
The dual-component system creates local quality differentiation where Component A contributes to reaction rate and Component B moderates the reaction speed and prevents defects. The specific combination ratio ensures balanced properties: sufficient reactivity without excessive speed that would cause manufacturing defects.
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 prevents excessive reaction rates, reduces stria formation, and improves glass transition temperature, resulting in lenses with uniform optical and mechanical properties.
Implementation Method 1
a polythiol composition including a plurality of thiol-based compounds... a first polythiol compound... and a second polythiol compound which has a molecular weight greater than that of the first polythiol compound
Data Source
AI summary
A polythiol composition according to exemplary embodiments includes a first polythiol compound and a second polythiol compound having a molecular weight greater than that of the first polythiol compound and the number of functional groups greater than or equal to the number of functional groups of the first polythiol compound. A content of the second polythiol compound is 500 ppm to 20,000 ppm based on a weight of the first polythiol compound. The reaction rate of an isocyanate-based compound may be controlled through the second polythiol compound, thus to suppress a stria phenomenon and improve mechanical properties of an optical product.