Polyester Resin Optical Lens High Refractive Index
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Solution Overview
Problem
Current optical lenses made from thermoplastic resins lack sufficient refractive index and dispersion for effective aberration correction, and existing polyester resins suffer from poor moldability and thermal stability.
Innovation Solution
A polyester resin composition with a diol constitutional unit derived from ethylene glycol (70-95%) and tricyclodecane or pentacyclopentadecane dimethanol (5-30%), combined with a dicarboxylic acid unit from naphthalenedicarboxylic acid (50% or more), which allows for high refractive index and low Abbe number, enabling injection molding with improved thermal stability and moldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large amount of fluorene dihydroxy compound is used to achieve high dispersion (low Abbe number), then the resin has sufficiently large dispersion, but the resin has considerably high melt viscosity and is poor in moldability
Solution Approach 1:
The patent changes the chemical structure parameters of the diol component by introducing cyclic structures (cyclohexane rings) and adjusting the carbon chain length. This structural modification reduces the melt viscosity of the resin while maintaining the low Abbe number property, thereby resolving the contradiction between dispersion and moldability
Solution Approach 2:
The patent creates a composite polyester resin system by combining specific diols (ethylene glycol, propylene glycol, cyclohexane dimethanol) with naphthalenedicarboxylic acid. This composite approach achieves both high dispersion (Abbe number 17-22) and good moldability through synergistic material composition
2Ease of manufacture
If the melt viscosity is lowered by increasing the molding temperature, then the moldability is improved, but coloration upon molding is intensified and the mold is contaminated with thermal decomposition products
Solution Approach 1:
The patent changes the chemical composition parameters of the resin to achieve lower melt viscosity at moderate temperatures. By selecting specific diols with appropriate molecular structures (including cyclic structures), the resin flows more easily without requiring high molding temperatures, thus preventing coloration and thermal decomposition
3Ease of manufacture
If the polymerization degree is decreased to lower the melt viscosity, then the moldability is improved, but the content of low molecular weight components in the resin is relatively increased to contaminate the mold
Solution Approach 1:
The patent changes the molecular structure parameters by introducing cyclic structures (cyclohexane rings) and adjusting the carbon chain length of the diol components. This structural modification reduces melt viscosity through improved molecular packing and reduced intermolecular forces, rather than by decreasing polymerization degree, thus avoiding the generation of low molecular weight contaminants
4Reliability
If optical glass is used to achieve excellent heat resistance, transparency, and dimensional stability, then these properties are improved, but the material cost is high, molding workability is poor, and productivity is low
Solution Approach 1:
The patent replaces expensive optical glass with a cost-effective thermoplastic polyester resin that can be easily molded and discarded or replaced. The resin achieves comparable optical and thermal properties at lower cost, enabling high-volume production of optical lenses through injection molding
Solution Approach 2:
The patent changes the material phase from inorganic glass to organic thermoplastic polymer, fundamentally altering the processing parameters. The resin can be molded at much lower temperatures using standard injection molding equipment, enabling mass production while maintaining excellent optical clarity and heat resistance
Data Source
AI summary
The present invention relates to a polyester resin including a diol constitutional unit and a dicarboxylic acid constitutional unit as main constitutional units, in which the diol constitutional unit contains from 70 to 95% by mol of a constitutional unit derived from ethylene glycol and from 5 to 30% by mol of a constitutional unit derived from tricyclodecane dimethanol or pentacyclopentadecane dimethanol, and the dicarboxylic acid constitutional unit contains 50% by mol or more of a constitutional unit derived from a naphthalenedicarboxylic acid, and an optical lens obtained by molding the polyester resin. According to the present invention, there are provided a polyester resin that has a high refractive index and a low Abbe number and can be molded into a good optical lens, and an optical lens obtained by molding the polyester resin.