HEUR Polymer Thickener for Aqueous Coating Wetting and Flow
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Solution Overview
Problem
Existing hydrophobically modified ethoxylated urethane (HEUR) thickeners in aqueous coating compositions fail to provide satisfactory substrate wetting, hiding properties, and flow properties.
Innovation Solution
A polymer with structural units of the form R1—X—(C═O)—NH—R2—NH—(C═O)—O—POA-R3—(O—POA-R4)n, where R1, X, R2, POA, and R4 are specifically defined organic groups, is used as a thickener, offering improved molecular weight distribution and polydispersity control, leading to enhanced performance in aqueous coating compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If random polymerization process is used to prepare HEUR thickeners, then the polymer can be produced with broad molecular weight distribution, but the coating composition exhibits poor substrate wetting, hiding properties, and flow properties
Solution Approach 1:
The patent changes the polymerization parameters by using controlled polymerization conditions with specific stoichiometric ratios (excess diisocyanate), controlled temperature (60-80°C), and extended reaction time (18-24 hours) to achieve narrow molecular weight distribution and high polydispersity index, thereby improving coating performance while maintaining manufacturability
Solution Approach 2:
The patent introduces specific structural features at the polymer ends (hydrophobic end groups from monoalcohol termination) and within the backbone (urethane linkages and polyether segments) to create localized functional regions that enhance substrate wetting and coating performance without compromising the overall polymer production process
2Quantity of substance
If higher thickener concentration is used in aqueous coating compositions, then the viscosity increases, but viscosity suppressants are required which affect the final product properties
Solution Approach 1:
The patent changes the polymer's molecular characteristics (narrow distribution, high PDI ≥2.0, specific end group structure) to achieve efficient thickening at lower concentrations (0.1-5.0 wt%), eliminating the need for viscosity suppressants and their associated harmful effects on coating performance
3Reliability
If polymer with narrow molecular weight distribution is produced, then the coating composition exhibits improved substrate wetting and flow properties, but the polymerization process requires more stringent control conditions
Solution Approach 1:
The patent performs preliminary action by pre-calculating and controlling the stoichiometric ratio (excess diisocyanate), pre-setting the reaction temperature (60-80°C), and pre-determining the reaction time (18-24 hours) to achieve narrow molecular weight distribution and high polydispersity index without requiring complex real-time process control during polymerization
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 polymer significantly improves substrate wetting, hiding properties, and flow properties in aqueous coating compositions, allowing for higher thickener concentrations without viscosity suppressants, thereby enhancing the formulation latitude of products like paint.
Implementation Method 1
The polymer of the invention can be used with great advantage as thickener, in particular as thickener in aqueous liquid compositions
Data Source
AI summary
The invention relates to polymer comprising structural units according to formula (I), R1—X—(C═O)—NH—R2—NH—(C═O)—O—POA-R3—(O—POA-R4)n wherein R1 represents an organic group terminated by a hydrocarbyl group having 6 to 50 carbon atoms, X represents O or N—R5, wherein R5 represents a hydrogen atom or a hydrocarbyl group having 1 to 30 carbon atoms, R2 represents an aliphatic hydrocarbyl group having 4 to 40 carbon atoms, POA represents a polyoxyalkylene group, R3 represents an organic group having 2 to 40 carbon atoms, n is an integer from 1 to 6, R4 is independently selected from —(C═O)—NH—R2—NH—(C═O)—X—R1, —(C═O)—NH—R1, —R6, wherein R6 represents a hydrogen atom or an aliphatic or aromatic group having 1 to 24 carbon atoms, and wherein the polymer has an average of at least 1.8 end groups R1 per molecule, a number average molecular weight in the range of 2000 to 100000 Daltons, a polydispersity in the range of 1.0 to 5.0, wherein the quotient of the polydispersity divided by (n+1) is less than 1.0, with the proviso that the polymer is not the reaction product of a) the mono-adduct of isophorone diisocyanate with 1-dodecanol and b) a polyether based on glycerol and a mixture of ethylene oxide and propylene oxide with an OH number of 18 mg KOH/g.