Vinyl Ester Polymer Dispersion for Exterior Paints

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Solution Overview

Problem

Existing vinyl ester-based polymer dispersions used in paints and plasters suffer from high water permeability and whitening when exposed to moisture, along with insufficient resistance to dirt pickup and water resistance, limiting their suitability for exterior applications.

Innovation Solution

A multistage emulsion polymerization process is employed, incorporating controlled amounts of vinyl esters of longer chain carboxylic acids and comonomers with acid functionality in the first and second stages to produce vinyl acetate/acrylic polymer dispersions, enhancing resistance to whitening and reducing water uptake.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If vinyl ester-based copolymer dispersions are used for low temperature film formation, then film formation capability is improved, but water resistance and dirt pickup resistance deteriorate

Engineering Contradiction:

Improvelow temperature film formationVSAvoidwater resistance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The polymerization process is divided into multiple stages: first stage produces polyvinyl ester particles with low Tg for film formation, second stage incorporates hydrophobic monomers (vinyl esters of C5-C18 unsaturated carboxylic acids) to create a core-shell structure where the shell provides water resistance while the core maintains low temperature film formation capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite polymer structure combining polyvinyl ester (for film formation) with hydrophobic vinyl ester components (for water resistance). The resulting copolymer dispersion contains both hydrophilic and hydrophobic segments, achieving a balance between film formation and water resistance

Inventive Principle:

Principle #40Composite materials

2Reliability

If polyvinyl ester dispersions with polymerized silanes and epoxides are used for weathering resistance, then weathering resistance is improved, but water permeability increases

Engineering Contradiction:

Improveweathering resistanceVSAvoidwater permeability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters by incorporating vinyl esters of unsaturated carboxylic acids with 5-18 carbon atoms, which have different hydrophobicity characteristics compared to traditional silane/epoxide systems. This parameter change achieves weathering resistance through molecular structure rather than crosslinking chemistry, thereby reducing water permeability

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If vinyl ester-based copolymer dispersions are used for interior applications, then block resistance is improved, but exterior application suitability deteriorates

Engineering Contradiction:

Improveblock resistanceVSAvoidexterior application suitability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The invention creates a universal polymer dispersion that can serve both interior and exterior applications. By incorporating hydrophobic vinyl ester components into the polymer structure, the dispersion gains water resistance and dirt pickup resistance while maintaining its block resistance, making it adaptable to both interior and exterior environments

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 resulting polymer dispersions exhibit reduced water take-up and whitening, maintaining low temperature film formation and high dirt-pickup resistance, making them suitable for exterior façade paints and plasters.

Implementation Method 1

vinyl ester-containing monomer mixtures are converted by free-radical polymerization by addition of initiators in the presence of protective colloids and/ or emulsifiers

Methodology Applied

Scientific EffectFree-radical polymerization:

Implementation Method 2

the hydroplastification effect of vinyl acetate, rendering them suitable binders for low-emission interior paints

Methodology Applied

Scientific EffectHydroplastification:

Data Source

PatentEP3810665B1Polymer dispersions, their preparation and use

Publication Date: 2025.11.12 CELANESE INTERNATIONAL CORP

AI summary

A multistage emulsion polymerization process comprises polymerizing a first monomer composition comprising from 50 to 95 weight percent of vinyl acetate, from 5 to 40 weight percent of at least one vinyl ester of a C5 to C18 unsaturated carboxylic acid, and optionally up to 40 weight percent of ethylene, all based on the total weight of monomers in the first monomer composition, to produce a first stage polymer. A second monomer composition comprising 40 to 89.95 weight percent of at least one ester of methacrylic acid or a vinyl aromatic monomer, 10 to 59.95 weight percent of at least one ester of acrylic acid, and from 0.05 to 10 weight percent of at least one comonomer with acid functionality, based on the total weight of monomers in the second monomer composition, is then polymerized in the presence of the first stage polymer to produce a second stage polymer.