Polyisocyanurate Plastics Low Shrinkage Trimerization
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Solution Overview
Problem
Existing processes for producing polyisocyanurate plastics from monomeric diisocyanates result in significant volume shrinkage and are time-consuming, requiring complex temperature control and are not suitable for producing transparent materials with high thermal durability and color stability.
Innovation Solution
Catalytic trimerization of a polyisocyanate composition with a high isocyanurate structure content, primarily consisting of oligomeric polyisocyanates, which reduces volume shrinkage and enables efficient production of transparent materials with high thermal durability and color stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If monomeric diisocyanates are used for polyisocyanurate production, then the material achieves high transparency, but significant volume shrinkage occurs during trimerization
Solution Approach 1:
The invention changes the molecular weight parameter of the starting polyisocyanate from monomeric to oligomeric (200-1000 g/mol), which fundamentally alters the trimerization behavior. This parameter change reduces the volume shrinkage during curing while maintaining the transparency required for optical applications
Solution Approach 2:
The invention applies different structural characteristics to different parts of the polymer system by using oligomeric polyisocyanates with specific molecular weight ranges and isocyanate group densities. This local optimization of molecular parameters achieves both low shrinkage and high transparency simultaneously
2Productivity
If monomeric diisocyanates are trimerized, then polyisocyanurate plastic is formed, but the process is time-consuming and requires complex temperature control
Solution Approach 1:
Changing from monomeric to oligomeric polyisocyanates fundamentally alters the reaction kinetics and thermal behavior. The oligomeric structure provides inherent thermal stability that simplifies temperature control requirements while accelerating the trimerization reaction to reduce production time
Solution Approach 2:
The oligomeric polyisocyanates are pre-synthesized with controlled molecular weights and isocyanurate structure contents (5-50%) before the final trimerization step. This preliminary structuring enables faster, more controlled curing with simplified temperature management
3Stability of the object's composition
If high isocyanurate structure content is achieved, then thermal stability improves, but volume shrinkage increases
Solution Approach 1:
The invention optimizes the isocyanurate structure content parameter to a specific range (5-50%) rather than maximizing it. Combined with using oligomeric polyisocyanates of controlled molecular weight, this parameter optimization achieves thermal stability while minimizing volume shrinkage during the trimerization reaction
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 process yields transparent polyisocyanurate plastics with low volume shrinkage and high thermal and color stability, suitable for applications such as LED encapsulation, with improved processing efficiency and reduced heat removal requirements.
Implementation Method 1
catalytic trimerization of a polyisocyanate composition A) which contains oligomeric polyisocyanates
Implementation Method 2
a considerable shrinkage in volume occurs in the course of a trimerization reaction
Data Source
AI summary
The present invention relates to a polyisocyanurate plastic obtainable by catalytic trimenzation of a polyisocyanate composition A) which contains oligomeric polyisocyanates and is low in monomeric diisocyanates, where the isocyanurate structure content in the polyisocyanate composition A) is at least 50 mol %, based on the sum total of the oligomeric structures from the group consisting of uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and oxadiazinetrione structure that are present in the polyisocyanate composition A). The present invention further relates to a transparent element comprising or consisting of the polyisocyanurate plastic. The invention likewise relates to a process for producing the polyisocyanurate plastics.