Polycarbodiimide Compound Resolving Amine Residue in Polyester Resins
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Solution Overview
Problem
Urea-modified carbodiimides used in polyester resins often leave residual amines due to high boiling point amine compounds, which can degrade upon heating and increase melt viscosity, compromising processability and hydrolysis resistance.
Innovation Solution
A polycarbodiimide compound with capped terminal isocyanate groups using amine compounds with boiling points ≤150°C and a specific degree of polymerization, such as cyclohexylamine and diisopropylamine, is developed to minimize residual amines and enhance processability while maintaining hydrolysis resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an amine compound with high boiling point (≥150°C) is used to introduce urea bonds, then hydrolysis resistance is improved, but residual amine increases and processability deteriorates
Solution Approach 1:
The patent changes the boiling point parameter of the amine compound from ≥150°C to <150°C, which fundamentally alters the outcome of the urea bond formation process. This parameter change enables complete vaporization of the amine compound during processing, eliminating residual amine while maintaining hydrolysis resistance through the carbodiimide structure.
Solution Approach 2:
The patent converts the potentially harmful effect of amine compound residue into a beneficial process. By selecting amine compounds with boiling points <150°C, the amine serves its purpose in forming urea bonds and then completely vaporizes during processing, transforming what could be a harmful residue into a temporary reagent that disappears, leaving only the beneficial carbodiimide structure.
2Reliability
If urea-modified carbodiimide with high degree of polymerization (n=10) is used, then hydrolysis resistance is improved, but melt viscosity increases and processability worsens
Solution Approach 1:
The patent optimizes the degree of polymerization parameter n from 10 to a specific range of 1-5. This parameter change balances the competing requirements: sufficient carbodiimide groups (n≥1) to provide hydrolysis resistance while limiting the chain length to maintain acceptable melt viscosity and processability (n≤5).
Solution Approach 2:
The patent applies partial action by using a moderate degree of polymerization (n=1-5) rather than maximum polymerization (n=10). This partial approach provides sufficient hydrolysis resistance through the carbodiimide groups while avoiding the excessive chain length that would cause problematic viscosity increase, achieving the minimum necessary effect with optimal properties.
3Productivity
If amine compound with high boiling point is used, then urea bond formation is efficient, but residual amine remains and adversely affects polyester resin performance
Solution Approach 1:
The patent converts the potential harm of amine residue into a benefit by selecting amine compounds with boiling points <150°C. These amines complete the urea bond formation efficiently and then completely vaporize during processing, transforming the potential contaminant into a temporary reagent that disappears, leaving only the beneficial carbodiimide structure in the final product.
Solution Approach 2:
The patent utilizes the phase transition (vaporization) of the amine compound to eliminate residual amine. By selecting amine compounds with boiling points <150°C, the amine undergoes complete phase transition from liquid to gas during the processing temperature range, effectively removing it from the final polyester resin product while maintaining the integrity of the carbodiimide structure.
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 polycarbodiimide compound achieves high-quality production with low residual amines, improving hydrolysis resistance and processability of polyester resins without deteriorating their performance.
Implementation Method 1
terminal isocyanate groups are capped by an amine compound having a predetermined boiling point
Implementation Method 2
amine compound having a boiling point of 150°C or lower... the amine compound may remain in a polyester resin composition including the urea-modified carbodiimide without vaporizing
Data Source
AI summary
Provided are a polycarbodiimide compound and a polyester resin composition and polyester resin modifier using the polycarbodiimide compound, the polycarbodiimide compound having a small amount of residual amine and having good processability when the polycarbodiimide compound is added to the polyester resin while keeping hydrolysis resistance of polyester resin imparted thereto through addition of the polycarbodiimide compound. A polycarbodiimide compound represented by the following general formula (1): RmNH2-m-CO-NH-Z-(N=C=N-Z)n-NH-CO-NH2-mRm (1) is used, wherein Rm is a hydrocarbon residue of an amine compound which is represented by RmNH3-m and has a boiling point at 1 atm of 150°C or lower; m is 1 or 2; Z is a residue obtained by removing two isocyanate groups from an aliphatic diisocyanate compound; and n is any integer of 2 to 7.