Solvent-Borne Polyamide Urethane Coatings via Segmented Architecture
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Solution Overview
Problem
Conventional polyamide-based coatings face challenges with hydrogen bonding, making them difficult to process and incorporate solvents, leading to poor mechanical and barrier properties, especially in solvent-borne systems, and requiring hazardous organic solvents.
Innovation Solution
Development of thermoset polyamide-rich compositions using polyamide oligomers with specific terminal groups and softer polymer segments, combined with polyisocyanates or polyepoxides, to create solvent-swellable coatings with reduced solvent volatility and improved processability at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyamides are processed using conventional melt stage methods, then good mechanical properties are achieved, but processing difficulty increases due to hydrogen bonding and high melting temperature
Solution Approach 1:
The patent introduces softer polymer segments with lower glass transition temperatures into the polyamide structure, reducing the overall melting temperature and processing temperature requirements while maintaining mechanical properties through controlled composition and crosslinking
Solution Approach 2:
The patent creates composite polyamide structures by combining rigid polyamide segments (for strength) with softer polymer segments (for processability), forming a heterogeneous polymer system that balances mechanical performance and ease of processing
2Ease of manufacture
If solvent-borne polyamide compositions are made with common solvents, then processability improves, but mechanical and barrier properties deteriorate due to poor solvent-polyamide compatibility
Solution Approach 1:
The patent modifies the polyamide structure by incorporating softer segments that increase compatibility with common solvents at processing temperatures, allowing solvent-borne applications without sacrificing film strength or barrier properties after solvent evaporation
Solution Approach 2:
The patent creates local regions of softer polymer segments within the polyamide structure that specifically interact with solvents, while maintaining rigid polyamide crystalline domains that provide mechanical strength and barrier properties in the final coating
3Strength
If polyamide molecular weight is increased to improve mechanical properties, then strength increases, but solvent compatibility decreases making processing difficult
Solution Approach 1:
The patent divides the polyamide into distinct segments: rigid high-molecular-weight polyamide segments (for strength) and softer lower-molecular-weight segments (for solvent compatibility), creating a segmented polymer architecture that balances both requirements
Solution Approach 2:
The patent forms a composite polymer system where high-molecular-weight polyamide provides mechanical strength while embedded softer polymer segments maintain solvent compatibility during processing, achieving both goals simultaneously
4Ease of operation
If hazardous organic solvents are used to achieve low viscosity coatings, then ease of application improves, but environmental harm and safety issues increase
Solution Approach 1:
The patent changes the viscosity parameters of the coating formulation by incorporating softer polymer segments that act as internal plasticizers, reducing viscosity and improving applicability without requiring hazardous organic solvents
Solution Approach 2:
The patent extracts or eliminates hazardous organic solvents from the formulation by replacing their function with softer polymer segments that provide similar flow and application properties through intrinsic molecular flexibility rather than volatile carrier substances
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 solution results in coatings with enhanced mechanical and barrier properties, reduced solvent usage, and improved adhesion to various substrates, while minimizing hazardous solvent release and environmental impact.
Implementation Method 1
thermoset polyamide-rich compositions using polyamide oligomers with specific terminal groups and softer polymer segments, combined with polyisocyanates or polyepoxides, to create solvent-swellable coatings
Implementation Method 2
create solvent-swellable coatings with reduced solvent volatility and improved processability at room temperature
Data Source
AI summary
The present invention relates to thermoset polymer solution, such as a polyurethanes and/or polyureas that include sufficient polyamide to give polyamide strength, adhesion, and durability, wherein the polymer solutions can be prepared as a one-component or two component solvent-borne coating composition. The polyamides give a harder, more chemical resistant, and often tougher thermoset, than similar water-borne polyurethanes rich in polyamide. The compositions of this disclosure differ from other polyamides as they have been formulated to be appropriate viscosity to use as coatings and then have crosslinking technology to form hard thermoset films.