Aqueous Urethane Resin Composition for Coatings
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Solution Overview
Problem
Active energy ray-curable water-containing resin compositions face challenges in achieving both emulsification or dispersion stability in water and adhesion to substrates after curing, which are essential for practical applications.
Innovation Solution
An aqueous polyurethane resin composition is developed by reacting a polyisocyanate, a polyoxyethylene side chain-containing diol, and a (meth)acrylic acid ester, with specific ratios and structures to ensure stability and adhesion, and cured using active energy rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a water-containing resin composition is formulated to improve emulsification stability, then dispersion stability in water is enhanced, but adhesion to substrates after curing deteriorates
Solution Approach 1:
The invention introduces a gradient structure within the polyurethane resin molecule: the polyoxyethylene side chains (20-95 wt.%) provide hydrophilic local quality for water dispersion stability, while the main chain containing hydroxyl groups and reactive double bonds provides hydrophobic local quality for substrate adhesion. This local differentiation of properties within the molecular structure resolves the contradiction between water stability and substrate adhesion.
Solution Approach 2:
The invention creates a composite polyurethane resin structure by combining multiple functional components: polyoxyethylene side chains for water compatibility, hydroxyl groups for hydrogen bonding with substrates, and polymerizable double bonds for crosslinking. This composite molecular architecture integrates both water dispersion stability and substrate adhesion capabilities within a single resin system.
2Stability of the object's composition
If the polyoxyethylene group content is increased to improve water dispersion stability, then emulsification stability is enhanced, but the resin becomes overly hydrophilic reducing adhesion performance
Solution Approach 1:
The invention optimizes the polyoxyethylene group content parameter to a specific range (20-95 wt.%) rather than using extreme values. This parameter optimization balances the hydrophilic-lipophilic ratio, ensuring sufficient water dispersion stability while maintaining adequate hydrophobic character for substrate adhesion, thus resolving the contradiction through precise parameter control.
3Strength
If conventional polyurethane resins are used to achieve adhesion, then substrate bonding is improved, but emulsification stability in water deteriorates
Solution Approach 1:
The invention segments the polyurethane resin structure into distinct functional domains: polyoxyethylene side chains segregated for water interaction, and main chain segments containing hydroxyl groups and double bonds for substrate interaction and crosslinking. This structural segmentation allows each domain to independently fulfill its function, resolving the contradiction between water stability and adhesion.
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 satisfactory emulsification and dispersion stability, providing long-term storage stability and excellent adhesion and water resistance after curing, enhancing coating properties.
Implementation Method 1
an aqueous urethane resin composition containing an aqueous urethane resin cured with active energy rays
Data Source
AI summary
Disclosed is an aqueous urethane resin composition containing an aqueous urethane resin obtained by reacting at least a polyisocyanate, a polyoxyethylene side chain-containing diol containing 20 to 95% by weight of a polyoxyethylene group in a mid portion of a side chain branched from a main chain having a hydroxyl group at both ends, and a (meth)acrylic acid ester containing at least one hydroxyl group, and cured by irradiation with an active energy ray; and water.