Dinorbornane Polyester Resin Heat Resistance Transparency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polyester resins face issues with insufficient heat resistance, intense coloration, and poor hue, as well as impaired transparency due to crystallinity in thick molded articles.
Innovation Solution
A polyester resin comprising a diol unit derived from a decahydro-1,4:5,8-dimethanonaphthalene ring skeleton, combined with specific dicarboxylic acid units, achieving a glass transition temperature of 90° C. or higher and a low crystallization exothermic peak, while maintaining excellent transparency and hue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional PET is used, then excellent transparency and mechanical strength are achieved, but glass transition temperature is insufficient and crystallinity impairs transparency in thick molded articles
Solution Approach 1:
The patent modifies the chemical structure of the diol component by introducing a dinorbornane ring system with specific substituents (R = H, CH3, or C2H5), which changes the molecular parameters to achieve both higher glass transition temperature (90°C or higher) and suppressed crystallinity, thereby maintaining transparency in thick molded articles
Solution Approach 2:
The patent creates a composite polyester resin system combining terephthalic acid units with the novel dinorbornane-derived diol units in specific ratios (20-100 mol% of the diol constitutional unit), achieving synergistic effects that simultaneously improve heat resistance and maintain optical clarity
2Illumination intensity
If 1,4-cyclohexanedimethanol is used for copolymerization, then transparency is improved, but glass transition temperature remains around 80°C with insufficient heat resistance
Solution Approach 1:
The patent replaces 1,4-cyclohexanedimethanol with a novel dinorbornane-derived diol featuring a rigid bicyclic structure with specific substituents, which increases the glass transition temperature to 90°C or higher while maintaining the transparency benefits through suppressed crystallinity
3Temperature
If bulky and rigid skeletons like tricyclodecanedimethanol are used, then glass transition temperature increases and crystallinity is suppressed, but coloration becomes intense and hue deteriorates
Solution Approach 1:
The patent introduces specific substituents (R = H, CH3, or C2H5) at particular positions on the dinorbornane ring structure, creating local structural variations that reduce chain rigidity and improve color stability while maintaining the overall bulky skeleton needed for high glass transition temperature and suppressed crystallinity
Solution Approach 2:
The patent optimizes the molecular parameters of the diol component by selecting specific dinorbornane derivatives with controlled substituent types and positions, achieving a balance between structural rigidity (for high Tg) and color stability (low YI value of 10 or less)
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 exhibits enhanced heat resistance, suppressed crystallinity, and improved transparency, making it suitable for applications requiring high heat resistance and optical clarity.
Implementation Method 1
a glass transition temperature is 90° C. or higher
Implementation Method 2
an amount of heat of a crystallization exothermic peak in temperature drop is 5 J/g or less
Data Source
AI summary
A polyester resin having a diol constitutional unit and a dicarboxylic acid constitutional unit, wherein 20 to 100 mol % of the diol constitutional unit is a constitutional unit derived from a diol having a dinorbornane ring; a glass transition temperature of the polyester resin is 90° C. or higher; an amount of heat of a crystallization exothermic peak in temperature drop of the polyester resin is 5 J/g or less; and a yellow index (YI) value as measured by a reflection method according to JIS K 7103 is 10 or less.