Phenyl Isocyanate Urethane Acrylates for High Refractive Index Coatings
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Solution Overview
Problem
Current methods for producing coatings with high refractive indices are either complex and expensive or limited in achievable refractive index values, and there is a need for materials that can be processed and combined with other components to adjust refractive indices for applications like optical components and holographic materials.
Innovation Solution
Development of specially substituted phenyl isocyanate-based urethane acrylates that can be cured to achieve high refractive indices and improved diffraction efficiency, suitable for use in optical lenses, antireflection coatings, and holographically writeable materials, through a process involving specific isocyanate-reactive compounds and catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metal oxides are deposited via sputter process, then refractive index greater than 2.0 is achieved, but process complexity and cost increase
Solution Approach 1:
The patent replaces the physical sputter deposition process with a chemical solution-based coating process. Organic polymers containing high refractive index elements (sulfur, halogen) are applied from solution and cured to form coatings with refractive indices up to 1.7, eliminating the need for complex vacuum sputtering equipment while achieving comparable optical performance.
Solution Approach 2:
The patent changes the chemical composition parameters of the coating material by incorporating high refractive index elements (sulfur, bromine, iodine) into the polymer structure. This chemical parameter modification allows achieving high refractive indices through molecular structure design rather than physical deposition processes.
2Ease of operation
If polymer coatings with high refractive index are used, then ease of application is improved, but achievable refractive index is limited to about 1.7
Solution Approach 1:
The patent creates composite polymer materials incorporating high refractive index elements (sulfur-containing groups, halogenated aromatic rings) into the polymer backbone or side chains. This composite approach combines the ease of polymer processing with the high refractive index properties of sulfur and halogen atoms, achieving refractive indices up to 1.7 through material composition rather than physical structure.
3Measurement precision
If halogen-substituted aromatic (meth)acrylates are used, then refractive index of 1.5 or higher is achieved, but preparation complexity increases
Solution Approach 1:
The patent develops a universal platform of sulfur-containing and halogenated polymer backbones that can accommodate various functional side groups. This universal structure allows achieving high refractive indices through the backbone composition while maintaining ease of manufacture by using standard polymerization techniques and commercially available monomers.
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 resulting coatings exhibit refractive indices greater than 1.50 and diffraction efficiency values above 25%, making them suitable for high-performance optical and holographic applications with improved efficiency in reference light usage.
Implementation Method 1
The suitability of substituted phenyl isocyanate-based urethane acrylates for the preparation of corresponding polymers has been described by Bowman (Polymer 2005, 46, 4735-4742)
Implementation Method 2
The interference field of signal and reference lightbeam (two planar waves in the simplest case) is mapped into a refractive index grating, which contains all information of the signal (the hologram), by the local photopolymerization at locations of high intensity in the interference field
Data Source
AI summary
Urethane acrylates of the general Formula (I), corresponding salts, solvates or solvates of a salt thereof:wherein R1, R2, R3, R4 and R5 each independently represent a substituent selected from the group consisting of hydrogen, halogens, C1-6-alkyls, trifluoromethyl, C1-6-alkylthios, C1-6-alkylselenos, C1-6-alkyltelluros, and nitro groups, with the proviso that at least one of R1, R2, R3, R4 and R5 is not hydrogen; R6 and R7 each independently represent a substituent selected from the group consisting of hydrogen and C1-6-alkyls; and A represents a saturated or unsaturated or linear or branched C1-6-alkyl radical or a polyalkylene oxide radical having 2-6 ethylene oxide or propylene oxide units; processes for producing and methods of using the same.