Cationic Polymer Rheology Modifiers for Architectural Coatings

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Solution Overview

Problem

Cellulose ethers in architectural coatings face challenges in providing efficient paint thickening, particularly at low shear and high shear rates, with high molecular weight requirements and limited dilution tolerance, necessitating improved rheology modifiers.

Innovation Solution

A rheology modifier composition comprising 50-99% water-soluble polymers and 1-50% cationic polymers, produced by polymerizing or copolymerizing quaternized monomers, is used to enhance paint thickening efficiency without increasing aqueous viscosity, incorporating cross-linkers and dispersants for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cellulose ether molecular weight is increased to improve paint thickening efficiency, then low shear viscosity improves, but aqueous viscosity increases and processing becomes more difficult

Engineering Contradiction:

Improvepaint thickening efficiencyVSAvoidaqueous viscosity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent combines cellulose ether with cationic polymer to create a composite rheology modifier system. The cationic polymer (1-50 wt%) interacts with the cellulose ether (50-99 wt%) to enhance thickening efficiency through synergistic effects, allowing use of lower molecular weight cellulose ether while achieving target viscosity without excessive aqueous viscosity buildup

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical parameters of the rheology modifier by introducing cationic functional groups through quaternized monomers. This chemical modification alters the interaction mechanisms with paint components, enabling improved thickening at lower molecular weights and reducing the need for high molecular weight cellulose ether

Inventive Principle:

Principle #35Parameter changes

2Strength

If cellulose ether dosage is increased to improve high shear viscosity, then paint thickening improves, but dilution tolerance decreases

Engineering Contradiction:

Improvehigh shear viscosityVSAvoiddilution tolerance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The composite system of cellulose ether and cationic polymer provides dual mechanisms for viscosity control: cellulose ether contributes to base viscosity while cationic polymer enhances shear-thinning behavior and reological stability. This combination maintains high shear viscosity at lower dosages and improves dilution tolerance through synergistic interactions

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The cationic polymer provides localized enhancement of rheological properties through its charged groups that interact specifically with paint components. This localized action at interfaces and boundaries enhances high shear viscosity without requiring uniform distribution throughout the entire paint volume, thereby improving dilution tolerance

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 solution effectively increases low and high shear viscosities and improves dilution tolerance, providing enhanced thickening properties to architectural coatings while maintaining efficient use of resources.

Implementation Method 1

synthetic thickeners which provide the rheology by hydrophobic association

Methodology Applied

Scientific EffectHydrophobic association:

Implementation Method 2

cationic polymer, wherein the cationic polymer is produced by polymerizing a quaternized monomer

Methodology Applied

Scientific EffectElectrostatic interactions:

Data Source

PatentUS9834695B2High efficiency rheology modifers with cationic components and use thereof

Publication Date: 2017.12.05 HERCULES LLC

AI summary

The presently disclosed claimed inventive concept(s) relates generally to a rheology modifier composition and an aqueous protective coating composition containing the rheology modifier composition. More particularly, the presently disclosed and/or claimed inventive concept(s) relates to a rheology modifier composition comprising (a) about 50 to about 99% by weight of a water soluble polymer and about 1 to about 50% by weight of a cationic polymer, wherein the cationic polymer is produced by polymerizing a quaternized monomer or by polymerizing a quaternized monomer and a non-quaternized monomer. Additionally, the presently disclosed and/or claimed inventive concept(s) relates generally to the methods of making the rheology modifier composition and the aqueous protective coating composition.