Polyurethane-Urea Dispersions with Terminal PEG Anchoring
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Solution Overview
Problem
Aqueous polyurethane dispersions known in the state of the art exhibit inadequate stability in storage, particularly at elevated temperatures, leading to premature coagulation and inadequate conductivity for certain applications.
Innovation Solution
The development of aqueous polyurethane-urea dispersions with monofunctional PEG-containing components terminally anchored on the polyurethane chain, comprising specific weight ratios and molar masses of aliphatic polyisocyanate, polyhydroxy, polyethylene-glycol, and polyamine compounds, which enhance thermal stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If non-ionic stabilisation is used with PEG chains, then conductivity is reduced, but thermal stability deteriorates at temperatures higher than 60°C
Solution Approach 1:
The patent applies local quality by differentiating the functional roles of different PEG incorporation positions. Terminal PEG groups provide hydrophilicity and stability, while avoiding lateral PEG groups that cause premature coagulation. This localized functional differentiation resolves the contradiction by placing stabilizing groups only where they provide benefit without harmful side effects.
Solution Approach 2:
The patent creates a composite polyurethane structure combining hydrophobic polyurethane segments with hydrophilic terminal PEG groups. This composite architecture allows the material to exhibit both low conductivity (from the polyurethane matrix) and improved thermal stability (from the terminal PEG groups), resolving the contradiction between these two properties.
2Strength
If lateral PEG incorporation is used, then mechanical properties are improved, but coagulation stability deteriorates
Solution Approach 1:
The patent extracts the problematic lateral PEG groups from the polyurethane structure and replaces them with terminal PEG groups. This removal of the harmful lateral incorporation while retaining the beneficial terminal hydrophilicity resolves the contradiction by eliminating the source of premature coagulation while maintaining mechanical integrity through the terminal anchoring.
Solution Approach 2:
The patent applies local quality by concentrating PEG functionality at the terminal positions rather than distributing it laterally throughout the polymer chain. This localized placement provides hydrophilicity for stability without the harmful lateral interactions that cause coagulation, while mechanical properties are maintained through the overall polymer structure.
3Stability of the object's composition
If bifunctional PEG-containing emulsifiers are used, then thermal stability is improved, but manufacturing complexity increases due to additional process steps
Solution Approach 1:
The patent merges the hydrophilizing function and the terminal anchoring function into a single monofunctional PEG component. This consolidation eliminates the need for separate emulsifier synthesis steps required by bifunctional approaches, reducing manufacturing complexity while maintaining thermal stability through terminal PEG incorporation.
Solution Approach 2:
The patent uses commercially available monofunctional PEG compounds as simple, off-the-shelf components rather than requiring complex in-situ synthesis of bifunctional emulsifiers. This approach simplifies the manufacturing process by eliminating additional process steps while achieving the desired thermal 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 resulting polyurethane-urea dispersions demonstrate improved stability with a coagulation temperature of at least 75°C and low conductivity, suitable for various applications including electronics and glass-fibre sizing materials.
Implementation Method 1
The non-ionic stabilisation is based on the incorporation of functional hydrophilic polyethylene oxides that are reactive with respect to isocyanate groups
Implementation Method 2
by water-soluble or partly water-soluble oligomer chains or polymer chains that are adsorbed on the surface or covalently bonded preventing an agglomeration by virtue of van der Waals interactions
Implementation Method 3
it is necessary that coatings exhibit a conductivity that is as low as possible, in order to guarantee high electrical insulation
Implementation Method 4
The resulting polyurethane-urea dispersions demonstrate improved stability with a coagulation temperature of at least 75°C
Data Source
AI summary
The present invention relates to aqueous non-ionically hydrophilised binding-agent dispersions based on polyurethane ureas with terminal polyethylene-oxide groups, to the preparation thereof, and to the use thereof for producing coatings.