Waterborne Polyurethane-Epoxy Primer Without Isocyanates
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Solution Overview
Problem
Existing waterborne primers struggle to provide comparable anti-corrosion performance to solvent-borne primers, limiting their use in refinishing vehicles and coating metal surfaces due to poor adhesion and environmental concerns from isocyanate-containing formulations.
Innovation Solution
A hybrid non-isocyanate polyurethane-epoxy waterborne primer is developed through a reaction between epoxy resin dispersion, polyurethane dispersion, and a non-isocyanate crosslinker component, forming a crosslinked polymer network with balanced properties, including adhesion and anti-corrosion, without using isocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solvent-borne primers are used to achieve good adhesion and anti-corrosion performance, then the coating performance is improved, but VOC emissions increase causing environmental harm
Solution Approach 1:
The invention changes the fundamental parameter of the coating medium from solvent-borne to waterborne, eliminating VOC emissions while maintaining performance through a hybrid polymer network formulation that combines epoxy and polyurethane dispersions in water
Solution Approach 2:
The invention creates a composite waterborne primer system combining epoxy resin dispersion, polyurethane dispersion, and non-isocyanate crosslinker to achieve the adhesion and anti-corrosion properties previously only attainable with solvent-borne formulations
2Object-generated harmful factors
If waterborne primers are used to reduce VOC emissions, then environmental performance is improved, but adhesion and anti-corrosion performance deteriorates
Solution Approach 1:
The invention formulates a composite waterborne primer combining epoxy resin dispersion providing adhesion and anti-corrosion, polyurethane dispersion providing flexibility and durability, and non-isocyanate crosslinker enabling crosslinked network formation to achieve performance comparable to solvent-borne primers
Solution Approach 2:
The invention changes the chemical structure and crosslinking mechanism of waterborne primers by using non-isocyanate crosslinkers with epoxy groups that react to form a crosslinked polymer network, achieving the density and durability previously only possible with isocyanate-based systems
3Reliability
If isocyanate-containing formulations are used to achieve good coating performance, then adhesion and durability are improved, but health and safety risks increase
Solution Approach 1:
The invention extracts and eliminates the harmful isocyanate component from the formulation while retaining the desired performance characteristics through alternative chemistry using epoxy groups and non-isocyanate crosslinkers
Solution Approach 2:
The invention uses epoxy groups as intermediary functional groups that can crosslink with non-isocyanate crosslinkers to form the same type of durable crosslinked network previously requiring isocyanates, providing an safer alternative pathway to achieve the same performance
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 hybrid primer achieves improved adhesion and anti-corrosion performance comparable to solvent-borne primers while reducing environmental and health risks, with lower VOC emissions and safer handling.
Implementation Method 1
a hybrid polymer network comprising crosslinked epoxy resin regions and isocyanate-free crosslinked polyurethane resin regions is formed
Implementation Method 2
isocyanate-free crosslinked polyurethane resin regions is formed
Data Source
AI summary
A 3K primer coating composition containing a waterborne epoxy resin dispersion; a polyurethane dispersion; and a curing component containing a combination of an amine and a non-isocyanate crosslinker component is provided, along with a primer coating formed from the composition. The coating includes a network of crosslinked epoxy resin regions and isocyanate-free crosslinked polyurethane resin regions. The crosslinked epoxy resin regions include units from an epoxy resin dispersion and an amine. The crosslinked polyurethane resin regions include units from a polyurethane dispersion and a non-isocyanate crosslinker component.