Diol-Based Polycarbonate Resins for High Refractive Index and Low Birefringence
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Solution Overview
Problem
Current resin materials with high refractive indices, such as those with naphthalene and fluorene structures, face challenges in manufacturing polycarbonate and polyester resins with high refractive indices and processability, including high glass transition points and costs, as well as issues with birefringence and coloration during processing.
Innovation Solution
A diol with specific structural formulas, including naphthalene and fluorene derivatives, is used to create polycarbonate and polyester resins with optimized refractive indices and processability, incorporating repeating units that enhance thermal stability and reduce birefringence, achieved through specific polymerization methods and copolymerization ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If resin materials with naphthalene or fluorene structures are used to achieve high refractive index, then the refractive index is improved, but the glass transition point becomes high and processing becomes difficult
Solution Approach 1:
The invention changes the chemical structure parameters of the polymer by introducing specific diol components with naphthalene or fluorene structures combined with flexible alkylene chains. This structural modification allows tuning of the glass transition point while maintaining high refractive index, thereby improving processability without sacrificing optical properties
Solution Approach 2:
The invention uses composite polymer structures combining rigid aromatic rings (naphthalene/fluorene) for high refractive index with flexible aliphatic chains for lower glass transition point. This composite approach at molecular level enables simultaneous achievement of high refractive index and improved processability
2Illumination intensity
If resin materials with naphthalene structures are used to achieve high refractive index, then the refractive index is improved, but birefringence increases
Solution Approach 1:
The invention introduces local flexible segments (alkylene chains) within the polymer structure to counterbalance the rigidity of naphthalene rings. This local quality modification reduces molecular orientation and stress-induced birefringence while maintaining the high refractive index contribution from the aromatic rings
Solution Approach 2:
By changing the chemical structure parameters to include specific ratios of rigid aromatic components and flexible aliphatic components, the invention optimizes the balance between refractive index and birefringence, achieving low birefringence despite high refractive index
3Ease of manufacture
If conventional polymerization methods are used for naphthalene-based resins, then production is simplified, but manufacturing cost increases and processability deteriorates
Solution Approach 1:
The invention employs readily available diol monomers and conventional polymerization catalysts, avoiding the need for expensive specialized reagents or complex multi-step synthesis processes. This approach reduces manufacturing cost while maintaining ease of production through standard industrial polymerization methods
Data Source
AI summary
A diol from which a resin material having high processability and a high refractive index can be manufactured, a polycarbonate resin and a polyester resin which is a polymer of the diol, and a molded article and an optical element formed of the polymer. The diol is represented by the general formula (1) shown below; the polycarbonate resin and the polyester resin are polymers thereof; and the molded article and the optical element are formed of the polymers,wherein R1 and R2 each independently denote one of a hydrogen atom and an alkyl group having 1 or more and 6 or less carbon atoms; Q denotes one of an oxyethylene group, a thioethylene group and a single bond.