Condensation Non-Isocyanate Polyurethane for Strong Epoxy Adhesion
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Solution Overview
Problem
Conventional non-isocyanate polyurethane compositions face challenges in achieving high structural strength, melt processability, and sufficient reactive functional groups for adhesion, often requiring organic solvents and generating liquid waste, while existing methods for preparing them are energy-intensive and environmentally unfriendly.
Innovation Solution
A condensation type non-isocyanate polyurethane composition comprising a first polyurethane and a second polyurethane in a specific molar ratio, synthesized through a carbamation and polycondensation process without purification steps, incorporating urea group-containing compounds, and using catalysts like stannous chloride to enhance adhesion and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If addition polymerization process is used to prepare NIPU, then the process is environmentally friendly, but high molecular weight products are difficult to obtain and structural strength is not optimal
Solution Approach 1:
The patent combines addition polymerization and condensation polymerization processes into a single reaction system. The addition polymerization provides environmental friendliness, while the condensation polymerization component enables获得 high molecular weight products and optimal structural strength through transesterification reactions between diamine-carbonate adducts and polyols.
Solution Approach 2:
The patent creates a composite polyurethane structure by incorporating both addition polymerization chains and condensation polymerization chains within the same material system. This composite approach allows the material to simultaneously achieve environmental benefits, high molecular weight, and enhanced structural strength through the synergistic combination of different polymerization mechanisms.
2Strength
If condensation polymerization process is used to prepare NIPU, then structural strength is improved, but the process requires purification steps and generates liquid waste
Solution Approach 1:
The patent converts the harmful effect of liquid waste generation into a beneficial process feature by using the liquid waste (containing unreacted diamine and carbonate) as a reaction medium for the condensation polymerization process. This eliminates the need for separate purification steps and transforms the waste problem into an advantage for maintaining reaction homogeneity and reducing energy consumption.
Solution Approach 2:
Instead of discarding the liquid waste generated during condensation polymerization, the patent recovers and reuses it as the reaction medium. The liquid waste containing unreacted diamine and carbonate is recovered and utilized to continue the polymerization reaction, thereby eliminating the need for purification steps and reducing liquid waste discharge.
3Strength
If polyurea is synthesized with strong hydrogen bonding force, then adhesion is improved, but temperature resistance deteriorates and organic solvent is required for processing
Solution Approach 1:
The patent changes the chemical structure parameters by incorporating carbonate groups and hydrocarbylene chains into the polyurea structure. This structural modification reduces the strength of hydrogen bonding forces while maintaining sufficient adhesion, and simultaneously improves temperature resistance by introducing flexible hydrocarbylene segments that reduce crystallinity and enhance thermal stability.
Solution Approach 2:
The patent creates a composite structure combining polyurea chains with carbonate groups and hydrocarbylene chains. This composite architecture provides multiple functions: the polyurea chains contribute to adhesion through hydrogen bonding, the carbonate groups provide structural stability, and the hydrocarbylene chains enhance temperature resistance and processability without requiring organic solvents.
4Manufacturing precision
If dicarbamate monomer is prepared by recrystallization, then purity is improved, but energy consumption increases and liquid waste is generated
Solution Approach 1:
The patent converts the harmful effect of energy consumption and liquid waste generation during recrystallization into a beneficial continuous process. By eliminating the recrystallization step and using the liquid waste directly as reaction medium, the process reduces energy consumption while maintaining product quality through the inherent homogeneity provided by the liquid phase reaction environment.
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 composition achieves high adhesion strength to epoxy resins and reduces environmental impact by minimizing liquid waste generation, with amine values ranging from 10 to 35 meq/kg, supporting applications in various industries.
Implementation Method 1
subjecting a diamine compound and a carbonate compound to a carbamation reaction so as to form a carbamate mixture
Implementation Method 2
subjecting the carbamate mixture and a diol compound to a polycondensation reaction so as to form a polyurethane composition
Implementation Method 3
a condensation polymerization process generally involves reacting diamine and carbonate, followed by a transesterification reaction with polyol
Implementation Method 4
using catalysts like stannous chloride to enhance adhesion and structural integrity
Implementation Method 5
Due to the presence of abundant hydrogen bonding forces between PHU molecules
Data Source
AI summary
A condensation type non-isocyanate polyurethane composition includes a first polyurethane represented by Formula (I) and a second polyurethane represented by Formula (II) in a molar ratio of the first polyurethane and to the second polyurethane ranging from 20:80 to 80:20, wherein each of the substituents in Formula (I) and Formula (II) is given the definitions as set forth in the Specification and Claims. The condensation type non-isocyanate polyurethane composition has an amine value of at least 10 meq/kg.