Cyclic Carbodiimide End-Sealing Suppresses Isocyanate Release
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Solution Overview
Problem
Existing carbodiimide compounds used for end-sealing polymers either liberate isocyanate compounds, leading to unpleasant work environments, or have low efficiency and stability issues due to their linear structure and high molecular weight, making them unsuitable for polymers with high melting points like polyesters.
Innovation Solution
A cyclic carbodiimide compound with a specific structure, containing one carbodiimide group and a cyclic structure of 8 to 50 atoms, is used as an end-sealing agent for polymers, which suppresses the production of free isocyanate compounds and provides efficient sealing without liberating isocyanate groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear carbodiimide compound is used as an end-sealing agent for polymers, then the polymer end can be sealed, but an isocyanate compound is liberated causing unpleasant smell and deteriorating work environment
Solution Approach 1:
The invention changes the molecular structure parameter from linear to cyclic carbodiimide compound. This structural parameter change prevents the liberation of isocyanate groups during the end-sealing reaction, thereby eliminating the unpleasant smell while maintaining sealing effectiveness.
Solution Approach 2:
The invention uses a cyclic carbodiimide compound that combines the carbodiimide functional group with a cyclic structural framework. This composite structure allows the compound to perform end-sealing function while preventing isocyanate liberation, thus resolving the contradiction between effectiveness and environmental harm.
2Reliability
If a macrocyclic carbodiimide compound is used, then the polymer end can be sealed, but the concentration is low and reaction takes many days reducing utility
Solution Approach 1:
The invention optimizes the ring size parameter of the cyclic carbodiimide compound (8 to 20 atoms) to achieve optimal balance between solubility/concentration and reaction efficiency. This parameter optimization enables complete reaction within 24 hours while maintaining end-sealing effectiveness, resolving the time loss issue.
3Reliability
If a macrocyclic carbodiimide compound with high molecular weight is used, then the polymer end can be sealed, but the efficiency is low
Solution Approach 1:
The invention changes the molecular weight parameter by using smaller cyclic structures (8 to 20 atoms) compared to macrocyclic compounds. This parameter change improves reaction efficiency and productivity while maintaining end-sealing effectiveness, as the smaller molecules can react more rapidly and completely.
4Reliability
If a macrocyclic carbodiimide compound with long chain is used, then the polymer end can be sealed, but it decomposes at high temperature making it unsuitable for high melting point polymers
Solution Approach 1:
The invention changes the structural parameter from long-chain macrocyclic to shorter cyclic structure (8 to 20 atoms). This parameter change enhances thermal stability, allowing the compound to withstand high temperatures during processing of high melting point polymers without decomposition, while maintaining end-sealing effectiveness.
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 cyclic carbodiimide compound effectively seals polymer ends without producing isocyanate odors, enhances polymer molecular weight, and can handle high-melting-point polymers, improving both environmental safety and industrial processes.
Implementation Method 1
a reaction for bonding the linear carbodiimide compound to an end of the polymer
Data Source
AI summary
A method of sealing an end of a polymer with a carbodiimide compound without liberating an isocyanate compound. A compound including a cyclic structure having one carbodiimide group whose first nitrogen and second nitrogen are bonded together by a bond group is used as an end-sealing agent for the polymer.