Bio-based Polyurethane Dispersion via Self-Emulsifying Polyol
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Solution Overview
Problem
Current polyurethane dispersion preparation methods require the addition of internal emulsifiers, which complicate the process and are not suitable for coating applications due to their properties, especially when using polyglyceride-derived polyester polyols.
Innovation Solution
A composition comprising bio-based polyol and polyhydroxy fatty acid compounds is prepared by mixing unsaturated fatty acid with polyhydric alcohol, adding organic acid and peroxide, and then water under acidic conditions, eliminating the need for internal emulsifiers and enhancing the polyurethane's ionic interaction and crosslinking properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal emulsifier is added to prepare polyurethane dispersion, then the dispersion stability is improved, but the process complexity increases and the coating performance deteriorates
Solution Approach 1:
The polyol itself serves as the emulsifying agent through its molecular structure containing both hydrophobic fatty acid chains and hydrophilic polyhydric alcohol groups, eliminating the need for separate internal emulsifiers. The polyol structure (I) with specific R groups and n values provides inherent amphiphilic properties that enable self-emulsification during the polyurethane formation process.
Solution Approach 2:
The polyol compound performs multiple functions simultaneously: it acts as both the polymer building block and the emulsifying agent. The molecular structure combines hydrophobic regions (fatty acid chains) and hydrophilic regions (polyhydric alcohol units), enabling the single compound to provide both structural integrity and dispersion stability without requiring additional specialized additives.
2Reliability
If internal emulsifier is used in polyurethane preparation, then the dispersion stability is improved, but the coating application performance deteriorates
Solution Approach 1:
The polyol structure (I) with variable R groups representing different polyhydric alcohol units provides self-emulsification capability while maintaining compatibility with various coating substrates and applications. The inherent amphiphilic structure allows the polyurethane to form stable dispersions without compromising adhesion, flexibility, or other coating performance characteristics.
Solution Approach 2:
The polyol molecule exhibits local quality differentiation with distinct hydrophobic fatty acid regions and hydrophilic polyhydric alcohol regions. This local amphiphilic character enables the polymer to interact differently with various components in the coating system, providing both dispersion stability and substrate compatibility for diverse coating applications.
3Ease of manufacture
If conventional polyol to fatty acid ratio (4:6 to 1:4) is used, then the polyester polyol can be prepared, but the polyurethane dispersion stability and performance are compromised
Solution Approach 1:
The invention inverts the conventional polyol to fatty acid ratio from 4:6 to 1:4 to a new ratio range of 1:4 to 6:4 (moles of polyhydric alcohol to moles of fatty acid). This parameter change in the stoichiometric ratio fundamentally alters the molecular structure to provide sufficient fatty acid chains for hydrophobic interactions while maintaining enough polyhydric alcohol units for hydrophilic character and crosslinking, thereby achieving both manufacturability and dispersion stability.
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 provides polyurethane dispersions with high strength, chemical, and heat resistance, suitable for adhesive and coating applications, while avoiding the complexity of internal emulsifier addition and leveraging bio-based materials.
Implementation Method 1
mixing fatty acid comprising unsaturated fatty acid and polyhydric alcohol at a ratio of 1 mole equivalent or more of carboxylic group from unsaturated fatty acid per a hydroxy group from polyhydric alcohol
Implementation Method 2
adding organic acid and peroxide compound into the mixture from step i.
Implementation Method 3
adding water into the mixture from step ii. under acidic condition
Implementation Method 4
enhancing the polyurethane's ionic interaction and crosslinking properties
Data Source
Figure 1
AI summary
This invention relates to a composition for a preparation of polyurethane dispersion, comprising bio-based polyol as shown in structure (I) and polyhydroxy fatty acid compound as shown in structure (II): wherein, R represents a polyhydric alcohol unit that is selected from aliphatic polyhydric alcohol, alicyclic polyhydric alcohol, cyclic polyhydric alcohol, aromatic polyhydric alcohol, or optionally, cyclic polyhydroxyl having heteroatom; R\ represents a hydrocarbon unit obtained from a molecular chain of unsaturated fatty acid having 14 - 24 carbon atoms and having from 1 - 6 pairs of vicinal diol group per one molecular chain of such unsaturated fatty acid; n represents an integer from 2 to 8 of an ester group obtained from a reaction of polyhydric alcohol and unsaturated fatty acid; wherein said composition is prepared from a process comprising the steps of: i. mixing fatty acid comprising unsaturated fatty acid and polyhydric alcohol at a ratio of 1 mole equivalent or more of carboxylic group from unsaturated fatty acid per a hydroxy group from polyhydric alcohol; ii. adding organic acid and peroxide compound into the mixture from step i.; iii. adding nucleophilic substance into the mixture from step ii. under acidic condition.