Two-Stage Polyisocyanurate Plastic Production
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Solution Overview
Problem
The production of fully cross-linked polyisocyanurate plastics is challenging due to the high exothermicity of the trimerization reaction, leading to temperature control issues, local hotspots, and incomplete conversion, especially in large-scale industrial applications, resulting in products with bubbles, discoloration, and suboptimal mechanical and chemical properties.
Innovation Solution
A two-stage process involving the catalytic polymerization of a polyisocyanate composition with two distinct catalysts, where the first stage produces a storage-stable polyisocyanate polymer with uretdione groups, which is then further trimerized at elevated temperatures to form a fully cured polyisocyanurate plastic, allowing for controlled heat dissipation and minimal material shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete trimerization is pursued to achieve high conversion, then polyisocyanurate plastic is formed with good temperature and chemical resistance, but the high exothermicity causes local hotspots and temperature control issues
Solution Approach 1:
The patent divides the single-stage trimerization process into two sequential stages: first forming uretdione groups at lower temperature (40-80°C), then converting to isocyanurate groups at higher temperature (80-150°C). This segmentation allows heat management by separating the highly exothermic trimerization into controlled steps, preventing local hotspots while achieving complete conversion and reliable polyisocyanurate plastic properties.
Solution Approach 2:
The patent performs preliminary formation of uretdione groups before completing the trimerization to isocyanurates. This preliminary action creates an intermediate structure that can be formed under milder conditions, then subsequently converted to the final isocyanurate structure. This approach prepares the system in advance for the second stage, allowing better temperature control during the most exothermic phase.
2Productivity
If trimerization is carried out in bulk bodies under adiabatic conditions, then large-scale industrial production is enabled, but temperature control becomes impractical due to heat accumulation
Solution Approach 1:
The patent segments the trimerization reaction into two distinct temperature stages, allowing bulk body processing while maintaining control. The first stage (uretdione formation) occurs at moderate temperatures suitable for heat dissipation in large volumes, while the second stage (isocyanurate formation) occurs after the most exothermic phase is complete. This enables scalable industrial production without sacrificing temperature control.
Solution Approach 2:
The patent changes the temperature parameter in two distinct steps: first maintaining 40-80°C for uretdione formation, then increasing to 80-150°C for isocyanurate formation. This parameter change strategy allows the process to adapt to bulk body conditions by controlling the exothermicity timeline, making large-scale production feasible while maintaining ease of manufacture through predictable thermal behavior.
3Reliability
If high temperature trimerization is used to achieve complete conversion, then polyisocyanurate plastic is formed, but product quality deteriorates due to bubbles and discoloration
Solution Approach 1:
The patent segments the conversion process into two quality-preserving stages: uretdione formation at lower temperature prevents premature side reactions, then isocyanurate formation completes conversion under controlled conditions. This segmentation achieves complete conversion (27) while avoiding the quality deterioration (29) that would result from single-stage high-temperature processing, as the most exothermic phase occurs when the product structure is already partially formed and more stable.
Solution Approach 2:
The patent performs preliminary formation of the uretdione structure before completing the isocyanurate conversion. This preliminary structural formation protects the developing polymer network from thermal degradation during the subsequent heating phase, ensuring that complete conversion is achieved without the bubbles and discoloration that would compromise manufacturing precision.
4Productivity
If monomeric diisocyanates with high isocyanate content are used, then reaction efficiency is improved, but the exothermicity increases making practical reaction difficult
Solution Approach 1:
The patent segments the energy release of high-isocyanate-content monomeric diisocyanates into two distinct phases: moderate energy release during uretdione formation, then additional energy release during isocyanurate formation. This segmentation maintains the productivity benefits of high-isocyanate monomers while controlling the exothermicity timeline, making practical reaction feasible by preventing thermal runaway even with highly reactive starting materials.
Solution Approach 2:
The patent changes the temperature parameter in response to the reaction progress: maintaining lower temperature (40-80°C) during the initial high-exothermicity phase of uretdione formation, then allowing higher temperature (80-150°C) during the second phase. This parameter change strategy enables the use of high-isocyanate-content monomers for improved productivity while managing their exothermicity through adaptive temperature control.
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
This process enables the production of polyisocyanurate plastics with improved mechanical and chemical resistance, reduced material shrinkage, and the ability to create deformable intermediates that can be further processed, meeting industrial requirements for precision components and coatings.
Implementation Method 1
catalytic polymerization of a polyisocyanate composition with two distinct catalysts, where the first stage produces a storage-stable polyisocyanate polymer with uretdione groups
Implementation Method 2
the thermal tone of the trimerization reaction to polyisocyanurate plastics starting from monomeric diisocyanates is very high (-75 kJ/mol NCO), especially with monomeric diisocyanates with a high isocyanate content
Implementation Method 3
which is then further trimerized at elevated temperatures to form a fully cured polyisocyanurate plastic
Data Source
AI summary
The invention relates to a method for producing a polyisocyanate polymer and to the polyisocyanate polymer obtainable from the method and to the use thereof as part of a two-stage method for producing a polyisocyanurate plastic, in particular for producing coatings, films, semi-finished products or molded parts containing such a polyisocyanurate plastic.