Microcapsule Interfacial Polymerization Using Dual-Size Emulsions

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Solution Overview

Problem

Existing methods for producing microcapsules, particularly those with water-soluble core agents, face challenges such as instability, complexity, and inefficiency, including the need for unsafe organic solvents and multi-step processes, and there is a demand for high-quality microcapsules that can encapsulate various materials effectively.

Innovation Solution

A method involving the formation of two types of emulsion particles differing in size, where one type has an average particle size of 0.1 to 300 µm and the other 0.01 to 30 µm, with a ratio of r/R ≤ 0.1, followed by interfacial polymerization to form microcapsules, using monomers like isocyanate and polyamine compounds to create a film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If microcapsules are produced by conventional methods, then production capacity is limited, but facility cost and processing time increase

Engineering Contradiction:
Improveproduction capacityVSAvoidfacility cost
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical microencapsulation equipment with a jet ink printer system that uses controlled ejection of core material and shell material through piezoelectric or thermal mechanisms to form microcapsules directly on substrates, eliminating the need for complex mechanical facilities

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The microcapsule formation process utilizes the substrate itself as part of the microcapsule structure, where the substrate surface serves as the base for microcapsule attachment, eliminating the need for separate collection and transfer facilities

Inventive Principle:
Principle #25Self-service

2Productivity

If microcapsules are produced by conventional methods, then production capacity is limited, but processing time increases

Engineering Contradiction:
Improveproduction capacityVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The jet ink printer system continuously ejects core and shell materials in a coordinated sequence without interruption, forming microcapsules in a continuous stream directly on the substrate, eliminating batch processing wait times and transfer operations

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system pre-positions core material droplets on the substrate before shell material is applied, ensuring that each microcapsule is formed with the correct core-shell structure in a single sequential operation rather than requiring multiple processing steps

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If microcapsules are produced by jet ink printer, then production capacity and precision are improved, but control of ejection timing and amount becomes critical

Engineering Contradiction:
Improvemicrocapsule uniformityVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control system monitors the ejection of core and shell materials in real-time and adjusts timing and quantities based on detected variations, ensuring consistent microcapsule formation despite variations in material properties or environmental conditions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts ejection parameters such as voltage amplitude, pulse duration, and ejection timing intervals to optimize microcapsule formation for different core materials, shell materials, and desired microcapsule sizes without changing the physical printer structure

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

This approach allows for the efficient production of stable microcapsules with high water content or pressure resistance, suitable for encapsulating hydrophobic substances, and enables the encapsulation of epoxy resin curing agents with improved storage stability.

Implementation Method 1

a jet ink printer is used to produce the microcapsules

Methodology Applied
Scientific EffectJet ejection: Jet

Data Source

PatentEP4190439B1Microcapsule production method
Publication Date: 2026.04.29 MORISHITA JINTAN CO LTD

AI summary

The present invention easily provides microcapsules by using a production method according to a more efficient and reliable interfacial polymerization method even when it is difficult to produce microcapsules by an interfacial polymerization method by adding a solution of a film-forming substance. Specifically, the present invention provides a method for producing microcapsules using two types of emulsion particles differing in size, the method comprising: an emulsion-forming step of separately forming two types of emulsions (1) and (2) whose continuous phases are common, wherein emulsion particles (1) of the emulsion (1) comprises one of two types of monomers which react with each other to form a film and emulsion particles (2) of the emulsion (2) comprises the other monomer; and a microcapsule-forming step of mixing and interfacial-polymerizing the emulsion (1) and the emulsion (2), wherein the emulsion particles (1) of the emulsion (1) have an average particle size (R) of 0.1 to 300 µm, the emulsion particles (2) of the emulsion (2) have an average particle size (r) of 0.01 to 30 µm, and r/R ≤ 0.1 is satisfied.