Voided Latex Particles with Functionalized Shells for Coating Opacity

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Solution Overview

Problem

Existing hollow latex particles used as opacifiers in paints and coatings often compromise performance properties such as wet adhesion, block resistance, and solvent resistance, necessitating the development of improved non-film-forming opacifying agents with enhanced characteristics.

Innovation Solution

The creation of voided latex particles with an outer shell polymer having a glass transition temperature of at least 45°C, bearing functional groups like 1,3-diketo, amino, and ureido, and a multi-stage emulsion polymerization process that involves swelling agents to create a hollow structure, which enhances the particles' performance by improving wet adhesion and block resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If hollow latex particles are used as opacifiers in paints and coatings, then opacity is improved, but wet adhesion and block resistance deteriorate

Engineering Contradiction:
ImproveopacityVSAvoidwet adhesion
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by creating a hollow latex particle with non-uniform structure: a polymer shell with specific Tg (45-150°C) surrounding a hollow core. The shell composition is specifically designed with functional groups (carboxyl, hydroxyl, amine, or imide groups containing 1-10 carbon atoms) to provide localized adhesion properties at the particle surface while maintaining the hollow structure for opacity. This resolves the contradiction by concentrating the adhesion-enhancing properties in the shell region rather than requiring the entire particle to be solid.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by controlling the glass transition temperature (Tg) of the outer shell polymer within a specific range of 45-150°C, and by controlling the functional group content at 0.1-10 weight percent of the shell polymer. These parameter optimizations allow the particle to achieve both good opacity (through the hollow structure) and improved wet adhesion (through the functionalized shell with controlled Tg and functional group content).

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If hollow latex particles are used as opacifiers in paints and coatings, then opacity is improved, but block resistance deteriorates

Engineering Contradiction:
ImproveopacityVSAvoidblock resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by creating a hollow latex particle with non-uniform structure: a polymer shell with specific Tg (45-150°C) surrounding a hollow core. The shell composition is specifically designed with functional groups (carboxyl, hydroxyl, amine, or imide groups containing 1-10 carbon atoms) to provide localized adhesion properties at the particle surface while maintaining the hollow structure for opacity. This resolves the contradiction by concentrating the adhesion-enhancing properties in the shell region rather than requiring the entire particle to be solid.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by controlling the glass transition temperature (Tg) of the outer shell polymer within a specific range of 45-150°C, and by controlling the functional group content at 0.1-10 weight percent of the shell polymer. These parameter optimizations allow the particle to achieve both good opacity (through the hollow structure) and improved block resistance (through the functionalized shell with controlled Tg and functional group content).

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If hollow latex particles are used as opacifiers in paints and coatings, then opacity is improved, but solvent resistance deteriorates

Engineering Contradiction:
ImproveopacityVSAvoidsolvent resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by creating a hollow latex particle with non-uniform structure: a polymer shell with specific Tg (45-150°C) surrounding a hollow core. The shell composition is specifically designed with functional groups (carboxyl, hydroxyl, amine, or imide groups containing 1-10 carbon atoms) to provide localized adhesion properties at the particle surface while maintaining the hollow structure for opacity. This resolves the contradiction by concentrating the adhesion-enhancing properties in the shell region rather than requiring the entire particle to be solid.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by controlling the glass transition temperature (Tg) of the outer shell polymer within a specific range of 45-150°C, and by controlling the functional group content at 0.1-10 weight percent of the shell polymer. These parameter optimizations allow the particle to achieve both good opacity (through the hollow structure) and improved solvent resistance (through the functionalized shell with controlled Tg and functional group content).

Inventive Principle:
Principle #35Parameter changes

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 voided latex particles effectively enhance the opacity and performance characteristics of coatings, including wet adhesion and block resistance, while maintaining non-film-forming properties, thereby improving the overall durability and appearance of painted surfaces.

Implementation Method 1

contacting multi-stage emulsion polymer particles comprising a core and an outer shell with a swelling agent, wherein the core comprises a hydrophilic component and is capable of being swollen with the swelling agent and wherein the swollen core causes said outer shell to expand

Methodology Applied
Scientific EffectSwelling: Absorption (physical)

Data Source

PatentEP3331697B1Voided latex particles containing functionalized outer shells
Publication Date: 2024.11.20 ARKEMA INC
  • EP3331697B1 patent drawingFigure 1
  • EP3331697B1 patent drawingFigure 2

AI summary

The wet adhesion of a coating composition may be improved through the use of voided latex particles as opacifying agents which contain a hollow interior as well as an outer shell of a polymer containing functional groups such as amino, 1,3-diketo, urea or ureido. Other types of functional groups may be introduced to the outer shell polymer in order to vary other desired characteristics of the coating. The voided latex particles are non-film-forming.