Resin Particle Emulsion Storage Stability

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Solution Overview

Problem

Conventional methods struggle to produce resin particle emulsions with large average particle diameters (1000 nm or larger) that are stable against separation and sedimentation, and existing techniques fail to achieve industrial-scale production of such emulsions with excellent polymerization stability.

Innovation Solution

An aqueous gel-encapsulating resin particle emulsion is developed, featuring a core-shell structure with an alkali-swellable core and a non-alkali-swellable outermost layer, where the core is swollen with water to achieve a high alkali swelling ratio, and the resin portion is thin, allowing for particle diameters up to 5000 nm with enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the average particle diameter of resin particle emulsion is increased to 1000 nm or larger, then the emulsion can meet industrial application requirements for large particle size, but the emulsion becomes inferior in storage stability and shows increased tendency toward separation and sedimentation

Engineering Contradiction:
Improveaverage particle diameterVSAvoidstorage stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The resin particle is divided into a core portion and a shell portion, creating a core-shell structure. The core contains the polymerization catalyst and monomer, while the shell provides structural stability. This segmentation allows the particle to maintain large size (1000 nm or larger) while the shell prevents separation and sedimentation, resolving the contradiction between particle size and storage stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure with a core portion containing polymerization catalyst and monomer, and a shell portion made of resin. This composite structure enables the particle to achieve both large diameter (1000 nm or larger for industrial applications) and high storage stability, as the shell provides mechanical strength and prevents aggregation while the core maintains functionality.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional emulsion polymerization is used to produce large particle emulsions, then the production process is simple, but the polymerization stability deteriorates and aggregates occur

Engineering Contradiction:
Improveproduction process simplicityVSAvoidpolymerization stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The polymerization catalyst and monomer are pre-loaded into the core portion before the emulsion polymerization process begins. This preliminary action ensures that the polymerization reaction occurs uniformly within the core, preventing aggregate formation and maintaining polymerization stability throughout the simple conventional emulsion polymerization process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The polymerization catalyst and monomer are localized within the core portion, while the shell portion provides a stable matrix. This local quality distribution ensures that polymerization occurs in a controlled manner within the core, preventing unwanted aggregation and maintaining reliability throughout the simple production process.

Inventive Principle:
Principle #3Local quality

3Strength

If the resin portion thickness is increased to provide structural stability, then the particle can maintain its form, but the alkali swelling ratio decreases and storage stability is compromised

Engineering Contradiction:
Improvestructural stabilityVSAvoidalkali swelling ratio
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The shell portion is designed as a thin film structure with controlled thickness (50-500 nm, preferably 100-300 nm). This thin shell provides sufficient structural stability to maintain particle form while allowing high alkali swelling ratio (200% or more) of the core portion, thereby maintaining storage stability. The shell acts as a flexible container rather than a rigid barrier.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The shell thickness is precisely controlled within the range of 50-500 nm (preferably 100-300 nm), which is thin enough to allow high alkali swelling (200% or more) while maintaining structural integrity. This parameter optimization resolves the contradiction between structural stability and alkali swelling ratio, enabling both large particle diameter and high storage stability.

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 solution effectively suppresses separation and sedimentation in resin particle emulsions with large particle diameters, achieving excellent storage stability and industrial applicability by maintaining a high alkali swelling ratio and thin resin thickness.

Implementation Method 1

the core portion is an aqueous gel encapsulating a solvent

Methodology Applied
Scientific EffectOsmosis: Osmosis

Implementation Method 2

making use of conventional emulsion polymerization

Methodology Applied
Scientific EffectEmulsion polymerization: Emulsion

Data Source

PatentEP3305820B1Aqueous gel-containing resin particle emulsion and method for preparing said aqueous gel-containing resin particle emulsion
Publication Date: 2020.11.25 SAIDEN CHEM IND
  • EP3305820B1 patent drawingFigure 1~2
  • EP3305820B1 patent drawingFigure 3~4
  • EP3305820B1 patent drawingFigure 5

AI summary

There is provided an aqueous gel-encapsulating resin particle emulsion which is excellent in storage stability such that the tendency to cause separation and sedimentation is suppressed even though the emulsion has particle diameters of 500 nm or larger, or further, 1000 nm or larger, and which can be utilized industrially effectively, and there is further provided a production method that is capable of stably producing the aqueous gel-encapsulating resin particle emulsion having the excellent properties by a simple method that is excellent in polymerization stability. An aqueous gel-encapsulating resin particle emulsion containing a particle that contains an alkali-swellable core portion containing a (meth) acrylic copolymer having an acid value of 200 to 400 mgKOH/g and a resin portion encapsulating the core portion and having a non-alkali-swellable outermost layer of the particle, the non-alkali-swellable outermost layer formed using a hydrophobic monomer, wherein the core portion is an aqueous gel encapsulating a solvent, the resin portion has a thickness of 5% or less of a diameter of the particle, and the particle has an average particle diameter of 500 nm or larger and 5000 nm or smaller, and a method for producing the emulsion.