Hydrophobically Modified Urethane Polymers for Waterborne Coatings
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Solution Overview
Problem
Existing methods for preparing hydrophobically modified alkylene oxide urethane branched polymers used in waterborne coatings do not achieve optimal rheological properties, leading to suboptimal sag-leveling balance in paints.
Innovation Solution
A process involving the reaction of a polyisocyanate compound with an excess of water-soluble polyalkylene glycol, followed by the addition of a diisocyanate and mono-functional compounds with isocyanate reactive moieties, under specific reaction conditions, to form hydrophobically modified alkylene oxide urethane branched polymers, which are then used as rheology modifiers in waterborne coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for preparing hydrophobically modified alkylene oxide urethane branched polymers are used, then the polymer can be synthesized, but the rheological properties are suboptimal and sag-leveling balance is poor
Solution Approach 1:
The patent applies parameter changes by using an excess of water-soluble polyalkylene glycol (5-10 times the molar amount required to react with the polyisocyanate) and specific molar ratios of diisocyanate (4-10 times) and mono-functional compounds (3-9 times) relative to polyisocyanate. These quantitative parameter modifications optimize the polymer structure to achieve superior rheological properties and sag-leveling balance compared to prior art methods
2Ease of manufacture
If a one-pot reaction with stoichiometric amounts of reagents is used, then the reaction is simpler, but the polymer structure and rheological properties are not optimized
Solution Approach 1:
The patent employs partial or excessive action by using an excess of water-soluble polyalkylene glycol (5-10 times the stoichiometric amount) in the first reaction step. This deliberate excess ensures complete reaction of the polyisocyanate while creating a polymer structure with optimized hydrophobic modification and branching, thereby achieving superior rheological properties without complicating the one-pot reaction approach
3Productivity
If the polyisocyanate compound reacts with stoichiometric amounts of polyalkylene glycol, then the reaction is more efficient, but the resulting polymer lacks optimal hydrophobic modification
Solution Approach 1:
The patent applies partial or excessive action by using 5-10 times the molar amount of water-soluble polyalkylene glycol relative to the polyisocyanate compound. This excess ensures complete consumption of the polyisocyanate (maintaining reaction efficiency) while providing sufficient hydrophobic chains for optimal hydrophobic modification and branching structure in the final polymer
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 described process results in polymers with superior rheological properties, improving sag-leveling balance and morphology compared to prior art compositions, leading to more desirable paint characteristics.
Implementation Method 1
contacting a polyisocyanate compound with a water-soluble polyalkylene glycol, under a first reaction condition, to form a first reaction mixture... the first reaction mixture comprising a water-soluble polyalkylene glycol and a poly-hydroxyalkylene oxide urethane
Implementation Method 2
contacting the first reaction mixture with a diisocyanate compound and one or more mono-functional compounds, having an isocyanate reactive functional moiety, under a second reaction condition, to form a second reaction mixture, the second reaction mixture comprising the hydrophobically modified alkylene oxide urethane branched polymer
Data Source
AI summary
Methods for preparing hydrophobically modified alkylene oxide urethane branched polymers. In an embodiment, the order of addition of reactants affects the properties of the resultant product urethane. In an embodiment, the time at which one or more reactants are added affects the properties of the resultant product urethane.