Polymerizable Composition Segmentation for Striae Suppression
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Solution Overview
Problem
The existing methods for producing polymerizable compositions for optical components, such as spectacle lenses, face issues with striae generation over time, even when stored for long periods, despite initial efforts to suppress striae and white turbidity by controlling moisture content.
Innovation Solution
A method involving the preparation of two compositions, A with a water content of 200 ppm or less containing a polyisocyanate component without a catalyst, and B with a water content of 1,000 ppm or less containing a polythiol component and a polymerization catalyst, which are then mixed to form a polymerizable composition, thereby avoiding the reaction of polyisocyanate with water and reducing striae formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the moisture content of the polymerizable composition is adjusted to 10 to 300 ppm to suppress striae and white turbidity, then the quality of the optical component is improved, but the composition shows noticeable changes over time and striae are likely to be generated after several hours of storage
Solution Approach 1:
The polymerizable composition is divided into two separate compositions: composition A containing the polyisocyanate component with water content of 200 ppm by mass or less, and composition B containing the polythiol component with water content of 1,000 ppm by mass or less. These compositions are prepared separately and then mixed immediately before use, preventing premature reaction and maintaining stability during storage while ensuring high quality upon mixing.
Solution Approach 2:
The polyisocyanate component (composition A) is prepared in advance with controlled low water content (200 ppm by mass or less) and stored separately without catalyst. The polythiol component (composition B) is also prepared in advance with controlled water content (1,000 ppm by mass or less) and includes the polymerization catalyst. This preliminary preparation of components with controlled water content prevents striae formation during storage while enabling quality polymerization when mixed.
2Duration of action of stationary object
If the polymerizable composition is stored for a long time period after preparation, then the workability and flexibility of the process is improved, but striae are generated at the time of producing the optical component
Solution Approach 1:
The composition is segmented into two stable components (A and B) that can be stored separately for extended periods without generating striae. Composition A (polyisocyanate with ≤200 ppm water) and composition B (polythiol with ≤1,000 ppm water) remain stable during storage. The striae problem is avoided by keeping these components separate until mixing, allowing flexible storage and timing while maintaining optical quality.
Solution Approach 2:
The water content parameters of the components are strictly controlled: composition A has water content of 200 ppm by mass or less, and composition B has water content of 1,000 ppm by mass or less. These parameter controls prevent premature reaction and striae formation during storage, enabling long-term storage while maintaining the ability to produce high-quality optical components when the compositions are mixed and polymerized.
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 approach effectively suppresses striae generation in optical components even after prolonged storage of the polymerizable composition, enhancing the stability and quality of the final optical components.
Implementation Method 1
a method for producing a resin for an optical material by polymerizing a polymerizable composition formed from a polythiol compound and a polyiso(thio)cyanate compound
Implementation Method 2
there is a problem that changes over time in the polymerizable composition are noticeable, and when several hours elapse from the preparation of the polymerizable composition, striae are likely to be generated
Data Source
AI summary
Provided is a method for producing a polymerizable composition, the method including: step (1) of preparing composition A having a water content of 200 ppm by mass or less, the composition A including a polyisocyanate component but not including a polymerization catalyst; step (2) of preparing composition B having a water content of 1,000 ppm by mass or less, the composition B including a polythiol component; and step (3) of mixing the composition A and the composition B and obtaining a polymerizable composition, and also provided is a method for producing an optical component, the method including: a step of injecting the above-mentioned polymerizable composition into a molding die; and a step of polymerizing the polymerizable composition.