Polyurethane Dispersion Hardness Chemical Resistance Dimer Fatty Acid
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Solution Overview
Problem
Conventional polyurethane dispersions face limitations in achieving a balance between flexibility, chemical resistance, and hardness in coatings, often compromising on one property for another.
Innovation Solution
A polyurethane dispersion is developed using a polyol comprising a combination of dimer fatty residues and furan dicarboxylic acid residues, which provides improved hydrolysis and chemical resistance while maintaining coating hardness, achieved by optimizing the weight ratio and content of these residues in the polyol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyurethane dispersions use traditional polyol formulations, then flexibility and chemical resistance can be achieved, but hardness is compromised
Solution Approach 1:
The patent uses a composite polyol formulation combining dimer fatty acid residues (providing flexibility and hydrolysis resistance) with furan dicarboxylic acid residues (providing hardness through crystalline/semi-crystalline structure). This composite approach allows simultaneous achievement of hardness and chemical resistance that cannot be obtained with single-component polyols
Solution Approach 2:
The patent creates different regions within the polyol structure with distinct properties: the dimer fatty acid portions provide flexible, hydrophobic regions for chemical resistance, while the furan dicarboxylic acid portions create rigid, crystalline regions for hardness. This local differentiation of material properties within the single polyol molecule resolves the contradiction
2Strength
If the polyol contains higher content of furan dicarboxylic acid residue to improve hardness, then coating hardness increases, but flexibility and hydrolysis resistance deteriorate
Solution Approach 1:
The patent optimizes the weight ratio parameter of furan dicarboxylic acid residue to dimer fatty acid residue within a specific range (1:4 to 4:1, preferably 1:2 to 2:1). By controlling this compositional parameter, the patent achieves the optimal balance between hardness (from furan) and flexibility (from dimer fatty acid) without sacrificing either property
3Reliability
If the polyol contains higher content of dimer fatty residue to improve flexibility and hydrolysis resistance, then chemical resistance improves, but hardness is reduced
Solution Approach 1:
The patent formulates a composite polyol where dimer fatty acid residues (amorphous, hydrophobic) provide hydrolysis resistance and flexibility, while furan dicarboxylic acid residues (crystalline) provide hardness. The synergistic combination in specific ratios (1:4 to 4:1 weight ratio) allows both properties to coexist
Solution Approach 2:
Within the polyol structure, dimer fatty acid segments create flexible, hydrophobic local regions that resist hydrolysis, while furan dicarboxylic acid segments create rigid, crystalline local regions that provide hardness. This spatial differentiation of functional regions resolves the property trade-off
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 resulting polyurethane dispersion offers enhanced flexibility, chemical resistance, and hardness, with improved processability and stability against thermo-oxidation and UV degradation, making it suitable for a wide range of coating applications.
Implementation Method 1
the dimer fatty residue may provide the flexibility and hydrolysis resistance due to its amorphous and hydrophobic nature
Implementation Method 2
the residue of a furan dicarboxylic acid may provide the hardness due to its crystalline or semi-crystalline nature
Implementation Method 3
improved processability and stability against thermo-oxidation and UV degradation
Data Source
AI summary
The present invention relates to a polyurethane dispersion comprising particles of a polyurethane dispersed in a dispersing medium, wherein the polyurethane is obtainable by reacting a polyol and an isocyanate, wherein the polyol comprises at least one dimer fatty residue selected from a dimer fatty diacid residue, a dimer fatty diol residue and a dimer fatty diamine residue; and at least one furan dicarboxylic acid residue. The invention also relates to a coating composition comprising the polyurethane dispersion, a polyol for making the polyurethane dispersion, the use of the polyol and a method of making the polyurethane.