Photocurable Composition for High Refractive Index Optical Materials
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Solution Overview
Problem
Current methods for achieving high refractive index in optical materials, such as using episulfide compounds, face limitations due to radical-inhibiting properties and poor light transmittance, and there is a need for a photocurable composition that can efficiently produce optical materials with refractive indices exceeding 1.73.
Innovation Solution
A photocurable composition comprising a cyclic compound, an episulfide compound, and a photopolymerization initiator, with optional thiol and acidic compounds, which minimizes optical activity inhibition and enhances refractive index, stability, and photocurability, allowing for the production of optical materials with refractive indices of 1.73 or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cyclic sulfur compound (S8) is used to enhance refractive index, then the refractive index increases, but optical activity is inhibited due to strong radical-inhibiting activity
Solution Approach 1:
The invention changes the chemical structure parameters of the cyclic sulfur compound by introducing specific substituents (Formula 1: where a to f are integers from 0 to 3 satisfying specific relationships). This structural modification reduces the radical-inhibiting activity while maintaining the high refractive index property, resolving the contradiction between enhancing refractive index and preserving optical activity.
Solution Approach 2:
The invention creates a composite photocurable composition containing the modified cyclic sulfur compound (a), episulfide compound (b), and photopolymerization initiator (c). This composite system combines materials with complementary properties: the cyclic sulfur compound provides high refractive index, the episulfide compound provides photocurability, and the initiator enables polymerization, achieving both high refractive index and preserved optical activity.
2Temperature
If inorganic particles are dispersed into organic resin to increase refractive index, then the refractive index increases, but light transmittance deteriorates due to light scattering
Solution Approach 1:
The invention changes from using inorganic particles to using a molecular-level cyclic sulfur compound with specific chemical structure (Formula 1). This parameter change from particulate to molecular scale eliminates light scattering while maintaining high refractive index, resolving the contradiction between increasing refractive index and preserving light transmittance.
3Productivity
If episulfide composition is photocured to achieve high refractive index, then productivity improves, but the refractive index is limited and cannot exceed 1.73
Solution Approach 1:
The invention creates a composite system combining cyclic sulfur compound (a) with episulfide compound (b) in specific proportions. The cyclic sulfur compound contributes to high refractive index while the episulfide compound ensures photocurability. This composite approach maintains the productivity benefits of photocuring while achieving refractive index exceeding 1.73.
Solution Approach 2:
The invention changes the chemical composition parameters of the photocurable system by incorporating the specific cyclic sulfur compound (Formula 1) with controlled substituent patterns. This parameter change enables the cured product to achieve refractive index above 1.73 while maintaining photocurability, overcoming the refractive index limitation of conventional episulfide compositions.
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 sufficient photo curability and a high refractive index, enabling the creation of high-performance optical materials with improved stability and optical properties.
Implementation Method 1
a photocurable composition comprising a cyclic compound (a), an episulfide compound (b) and a photopolymerization initiator (c)
Data Source
AI summary
According to the present invention, it is possible to provide a photocurable composition which comprises a cyclic compound (a) represented by formula (1), an episulfide compound (b), and a photopolymerization initiator (c). In a preferred embodiment, the proportion of the cyclic compound (a) in the photocurable composition is 5-80 mass %, the proportion of the episulfide compound (b) is 20-95 mass %, and the proportion of the photopolymerization initiator (c) is 0.1-10 parts by mass per 100 parts by mass of the sum of the cyclic compound (a) and the episulfide compound (b). In the formula, C represents a carbon atom, X represents S, Se, or Te, and a to f are integers of 0-3, provided that 8≥(a+c+e)≥1, 8≥(b+d+f)≥2, and (b+d+f)≥(a+c+e).