HEUR Thickener Viscosity Control via Hydrophobic End Groups

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Solution Overview

Problem

Existing paint thickeners fail to provide high viscosity at high shear rates while maintaining low viscosity at low shear rates, leading to inadequate dynamic and static behavior in paint compositions.

Innovation Solution

Development of a new HEUR-type thickener with specific hydrophobic groups at the ends of its chains, resulting from the condensation of an alcohol, poly(alkylene glycol), and polyisocyanate, which increases viscosity at high shear rates without significantly affecting low shear rates, allowing for a combination with pseudoplastic thickeners to achieve balanced rheological behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If existing paint thickeners are used, then viscosity at low shear rates is maintained, but viscosity at high shear rates is insufficient

Engineering Contradiction:

Improveviscosity at high shear ratesVSAvoidrheological behavior balance

Core Design Contradiction:

Stress or pressureVSAdaptability or versatility

Solution Approach 1:

The patent modifies the chemical structure of HEUR thickeners by incorporating specific hydrophobic groups (alkyl chains with 8-12 carbon atoms) at the ends of polyether chains. This structural parameter change enables the thickener to provide high viscosity at high shear rates while maintaining appropriate viscosity at low shear rates, resolving the contradiction between high-shear performance and overall rheological balance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molecular structure combining hydrophobic alkyl groups with hydrophilic polyether chains and urethane linkages. This composite structure allows the thickener to interact with both oil and water phases in paint formulations, providing enhanced thickening efficiency at high shear rates while maintaining stability at low shear rates.

Inventive Principle:

Principle #40Composite materials

2Productivity

If viscosity is increased at high shear rates, then dynamic behavior improves, but low shear rate viscosity may increase excessively

Engineering Contradiction:

Improvedynamic behaviorVSAvoidviscosity at low shear rates

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The thickener exhibits different thickening effects at different shear rates due to its specific molecular structure. The hydrophobic groups and polyether chains are arranged to provide selective interaction with paint components under different flow conditions, achieving high viscosity enhancement at high shear rates while limiting viscosity increase at low shear rates.

Inventive Principle:

Principle #3Local quality

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 new thickener exhibits high viscosity at high shear rates, enhancing dynamic behavior and low viscosity at low shear rates, providing a balanced rheological profile that can be adjusted by dose, suitable for various paint compositions, including satin and glossy paints.

Implementation Method 1

These products contain an associative compound comprising a carbon chain end and a methyl or ethyl branch

Methodology Applied

Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

The new thickener exhibits high viscosity at high shear rates, enhancing dynamic behavior

Methodology Applied

Scientific EffectShear thickening: Shear Thickening

Data Source

PatentEP3359584B1Thickener for aqueous systems, formulations containing same and uses

Publication Date: 2021.06.23 COATEX SA

AI summary

The present invention relates to novel associative thickeners belonging to the HEUR (Hydrophobically modified Ethyoxylated URethane) category and also to intermediate aqueous formulations containing such thickeners and to the final compositions, for example paint, lacquer, varnish or paper coating slip compositions.