Norbornene Crosslinked Polymer High Heat Resistance Curing
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Solution Overview
Problem
Current methods for producing norbornene-based crosslinked polymers do not achieve sufficient heat resistance for high-temperature applications, despite their potential, as they often result in polymers with glass transition temperatures below the required levels for demanding uses such as engine covers and encapsulation materials for power semiconductors.
Innovation Solution
A method involving the use of dicyclopentadiene, tetracyclododecene, and tricyclopentadiene-based monomers in high proportions, combined with a specific metathesis polymerization catalyst, undergoes primary and secondary curing at controlled temperatures to achieve a glass transition temperature of 240°C or higher, enhancing the polymer's heat resistance and insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional norbornene-based monomers are used with standard metathesis catalysts, then the polymerization process is simple, but the glass transition temperature remains below 240°C and insufficient heat resistance is achieved
Solution Approach 1:
The curing process is divided into two distinct stages: primary curing at temperatures below the catalyst deactivation temperature to form the polymer network, and secondary curing at temperatures above the catalyst deactivation temperature to achieve additional crosslinking and densification. This segmentation allows each stage to serve a specific function in achieving the target glass transition temperature of 240°C or higher.
Solution Approach 2:
The invention changes the temperature parameter dynamically during the curing process. By heating the polymer in two stages with different temperature ranges relative to the catalyst deactivation temperature, the physical and chemical properties of the polymer are modified to achieve superior heat resistance. The first curing stage uses moderate temperatures while the second stage uses elevated temperatures to complete the crosslinking.
2Temperature
If dicyclopentadiene, tetracyclododecene, and tricyclopentadiene-based monomers are used in high proportions (50% or more), then the glass transition temperature reaches 240°C or higher, but the monomer selection and配比 becomes more complex
Solution Approach 1:
The invention employs specific monomers with particular molecular structures (dicyclopentadiene, tetracyclododecene, and tricyclopentadiene) that have inherent properties conducive to achieving high glass transition temperatures. These monomers are selected based on their local molecular characteristics, including ring strain and crosslinking potential, which directly contribute to the thermal properties of the resulting polymer.
Solution Approach 2:
The polymer composition is designed as a composite system incorporating multiple norbornene-based monomers in specific proportions (50% or more of the total monomer content). This composite approach allows the synergistic effects of different monomer structures to achieve the target glass transition temperature while maintaining processability and performance.
3Reliability
If a two-stage curing process is implemented with temperature control relative to catalyst deactivation temperature, then super-high heat resistance is achieved, but the manufacturing process time and temperature control requirements increase
Solution Approach 1:
The primary curing stage is performed first at temperatures below the catalyst deactivation temperature to establish the basic polymer network structure. This preliminary action prepares the material for the subsequent secondary curing stage, where the catalyst deactivates and additional crosslinking occurs at elevated temperatures. This sequential approach optimizes the overall curing efficiency.
Solution Approach 2:
The curing process employs periodic temperature changes with two distinct heating stages. The first stage operates at moderate temperatures for initial polymerization, then the temperature is increased in the second stage to complete crosslinking. This periodic temperature control ensures thorough curing while managing the total process time and energy consumption.
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 norbornene-based crosslinked polymer exhibits super-high heat resistance with a glass transition temperature of 240°C or higher, along with improved insulation properties, making it suitable for applications requiring high thermal stability and electrical insulation, such as automotive engine covers and power semiconductor encapsulation.
Implementation Method 1
a method using a given metathesis catalyst
Implementation Method 2
heating a blend containing at least one member selected from the group consisting of dicyclopentadiene-based monomers, tetracyclododecene-based monomers, and tricyclopentadiene-based monomers, and a metathesis polymerization catalyst to a temperature lower than a deactivation temperature of the above metathesis polymerization catalyst to carry out a primary curing
Data Source
AI summary
The present invention relates to a norbornene-based crosslinked polymer containing at least one member selected from the group consisting of dicyclopentadiene-based monomer units, tetracyclododecene-based monomer units, and tricyclopentadiene-based monomer units in an amount of 50% by mass or more, wherein the norbornene-based crosslinked polymer has a glass transition temperature of 240°C or higher. Further, the present invention relates to a method for producing a norbornene-based crosslinked polymer as defined above, including step (1): heating a blend containing at least one member of the above monomer components, and a metathesis polymerization catalyst to a temperature lower than a deactivation temperature of the metathesis polymerization catalyst to carry out a primary curing; and step (2): heating a cured product obtained in the step (1) to a temperature equal to or higher than the deactivation temperature of the above metathesis polymerization catalyst to carry out a secondary curing. The norbornene-based crosslinked polymer of the present invention exhibits an effect of showing super-high heat resistance that its glass transition temperature is 240°C or higher.