Pentacyclopentadecane Polyester Resin Heat Resistance
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Solution Overview
Problem
Conventional polyester resins, such as those with a pentacyclopentadecane backbone, face challenges in achieving high heat resistance and maintaining transparency and mechanical strength, particularly when used in injection-molded articles, sheets, and containers, especially under high-temperature conditions like boiling disinfection or sterilization.
Innovation Solution
A polyester resin is developed through copolymerization of a specific diol with a pentacyclopentadecane backbone, where 50 to 90% of the diol unit is derived from pentacyclopentadecane dimethanol and 50 to 100% of the dicarboxylic acid unit is aromatic, with specific conditions for glass transition temperature and intrinsic viscosity to enhance heat resistance and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If PET is used for injection-molded articles, then transparency and mechanical strength are improved, but heat resistance is insufficient and whitening occurs at high temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester resin by incorporating specific diols (pentacyclopentadecane dimethanol, 1,3-propanediol, 1,4-butanediol) and controlling the glass transition temperature to 100-150°C and intrinsic viscosity to 0.3-1.0 dl/g. This parameter optimization simultaneously achieves high heat resistance and maintains transparency, resolving the contradiction between temperature resistance and transparency maintenance.
Solution Approach 2:
The patent creates a composite polyester resin system combining aromatic dicarboxylic acid units with specific aliphatic diol units having pentacyclopentadecane backbone. This composite structure leverages the high heat resistance of aromatic units while the specific diol units control crystallinity and transparency, achieving both heat resistance and transparency maintenance.
2Strength
If crystallinity is increased to improve mechanical strength, then strength is improved, but transparency deteriorates due to whitening
Solution Approach 1:
The patent optimizes the glass transition temperature parameter to 100-150°C and intrinsic viscosity to 0.3-1.0 dl/g, which controls the crystallization behavior. These parameter adjustments enable the resin to achieve sufficient mechanical strength while suppressing excessive crystallinity that causes whitening, thus maintaining transparency.
Solution Approach 2:
The patent introduces specific diol units with pentacyclopentadecane backbone that have unique molecular structures. These specific units create local regions in the polymer chain that control crystallization dynamics, allowing mechanical strength to be achieved through controlled crystallinity while preventing widespread whitening that would compromise transparency.
3Reliability
If copolymerization is increased to reduce crystallinity and prevent whitening, then transparency is improved, but glass transition temperature decreases and heat resistance worsens
Solution Approach 1:
The patent carefully controls the copolymerization parameters by limiting the content of specific diols (pentacyclopentadecane dimethanol 50-90%, 1,3-propanediol 5-30%, 1,4-butanediol 5-30%) and maintaining glass transition temperature within 100-150°C. This parameter optimization achieves transparency improvement through controlled crystallinity reduction while preventing excessive heat resistance loss.
Solution Approach 2:
The patent creates a composite copolymer system combining aromatic dicarboxylic acid units with specific aliphatic diol units. This composite structure reduces crystallinity and improves transparency while the aromatic units maintain adequate glass transition temperature and heat resistance, resolving the contradiction between transparency and heat resistance.
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 polyester resin exhibits improved heat resistance, transparency, and mechanical properties, allowing it to withstand high-temperature applications without significant deformation or whitening, making it suitable for food containers, medical instruments, and other demanding uses.
Implementation Method 1
A polyester resin is developed through copolymerization of a specific diol with a pentacyclopentadecane backbone, where 50 to 90% of the diol unit is derived from pentacyclopentadecane dimethanol and 50 to 100% of the dicarboxylic acid unit is aromatic
Implementation Method 2
both of the following conditions (1) and (2) are satisfied: (1) the measurement value of the glass transition temperature measured by a differential scanning calorimeter is 131°C or higher
Data Source
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AI summary
The polyester resin according to the present invention is a polyester resin containing a diol unit and a dicarboxylic acid uni t, wherein 50 to 95% by mol of the diol unit is a unit derived from pentacyclopentadecane dimethanol represented by a predetermined formula (I) and/or a unit derived from pentacyclopentadecane dimethanol represented by a predetermined formula (II), 50 to 100% by mol of the dicarboxylic acid unit is a unit derived from an aromatic dicarboxylic acid, and both of predetermined conditions (1) and (2) are satisfied.