Urethane Methacrylate Resin for Optical Sheets
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Solution Overview
Problem
Current resin materials for optical sheets, such as Fresnel lens sheets and liquid crystal display device backlights, face challenges in achieving high refractive index while maintaining low viscosity and formability, often resulting in crystallization and reduced brightness due to high aromaticity and viscosity issues.
Innovation Solution
A urethane (meth)acrylate resin is developed by reacting aromatic diisocyanate compounds with bisphenol-ethylene oxide adduct diols having multiple aromatic or alicyclic structures, combined with hydroxy-containing (meth)acrylate compounds, to achieve low viscosity and high refractive index, enabling the production of optical sheets with fine uneven shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an isocyanate compound with higher aromaticity is used to increase refractive index, then the refractive index is improved, but the resin material becomes highly viscous or crystallized
Solution Approach 1:
The patent changes the chemical structure parameters of the isocyanate compound by introducing aliphatic or alicyclic hydrocarbon groups into the aromatic ring structure. This structural modification reduces the aromaticity parameter while maintaining the refractive index at high levels (1.55 or higher), thereby preventing excessive viscosity and crystallization issues during manufacturing.
2Illumination intensity
If an isocyanate compound with higher aromaticity is used to increase refractive index, then the refractive index is improved, but the formability into optical sheet is deteriorated
Solution Approach 1:
The patent modifies the hydrocarbon group parameters in the isocyanate compound structure, specifically incorporating aliphatic or alicyclic groups with 1-20 carbon atoms. This structural parameter change maintains high refractive index while improving formability by preventing crystallization and reducing viscosity, enabling successful formation of optical sheets with fine uneven shapes.
3Illumination intensity
If a resin material with high refractive index is used to increase brightness, then the brightness is improved, but the viscosity increases making application difficult
Solution Approach 1:
The patent changes the molecular structure parameters of the resin material by using isocyanate compounds with specific hydrocarbon groups (aliphatic or alicyclic) attached to aromatic rings. This structural modification achieves high refractive index (1.55+) for improved brightness while maintaining low viscosity for easy application, resolving the contradiction between optical performance and manufacturability.
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 resin composition exhibits excellent formability into sheet-formed products with high refractive indices, suitable for optical applications, including plastic lenses, while minimizing crystallinity and viscosity, thus enhancing brightness and optical performance.
Implementation Method 1
A urethane (meth)acrylate resin produced by reacting aromatic diisocyanate compound (a), bisphenol-ethylene oxide adduct diol (b) having at least three aromatic ring or alicyclic structures in the molecule, and hydroxy-containing (meth)acrylate compound (c)
Implementation Method 2
optical sheets that are provided with fine uneven shapes on the surfaces and that realize predetermined functions by refracting light with the uneven structures
Data Source
AI summary
A urethane (meth)acrylate resin wherein the viscosity of the resin is low, the formability into a sheet-formed product, in particular, an optical sheet provided with fine uneven shapes on the surface is excellent, and a high refractive index can be realized, a curable resin composition including the urethane (meth)acrylate resin as an indispensable component, a cured product thereof, and a plastic lens are provided. A urethane (meth)acrylate resin produced by reacting aromatic diisocyanate compound (a), bisphenol-ethylene oxide adduct diol (b) having at least three aromatic ring or alicyclic structures in the molecule, and hydroxy-containing (meth)acrylate compound (c), which are indispensable raw material components, a curable resin composition containing the urethane (meth)acrylate resin as a primary component, and a cured product thereof.