Associative Polymer Oil Encapsulation via pH-Induced Solvation Cages

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Solution Overview

Problem

Existing methods for incorporating oils into aqueous formulations face challenges such as demixing, phase separation, and instability, which affect the aesthetic and rheological properties, as well as application performance, due to poor dispersion of the oil phase.

Innovation Solution

The process involves mixing an associative polymer consisting of (meth)acrylic acid, (meth)acrylic ester, and an associative hydrophobic monomer with oil and water, adjusting the pH to create solvation cages for oil molecules, and then precipitating these particles to achieve stable dispersion or isolation in water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If solvents or surfactant mixtures are used to stabilize the oil phase in water, then the oil dispersion is improved, but the formulation stability deteriorates due to demixing and phase separation

Engineering Contradiction:

Improveformulation stabilityVSAvoidoil dispersion quality

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent uses a specific polymer as an intermediary substance that mediates between the oil phase and aqueous phase. This polymer, containing both hydrophobic groups (for oil interaction) and hydrophilic groups (for water solubility), acts as a bridge to stabilize the oil-in-water emulsion without causing demixing or phase separation, thereby resolving the contradiction between formulation stability and oil dispersion quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention employs a composite polymer structure combining hydrophobic and hydrophilic segments in one molecule. This composite material design allows the polymer to simultaneously interact with both oil and water phases, creating a stable emulsion system that overcomes the limitations of using simple solvents or surfactants alone

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the oil phase is poorly dispersed in water, then the formulation simplicity is maintained, but the application performance deteriorates due to inhomogeneity

Engineering Contradiction:

Improveformulation simplicityVSAvoidapplication performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The polymer used in the invention exhibits self-assembly properties where it automatically organizes itself around oil droplets in the aqueous phase without requiring complex external processing. This self-service mechanism creates homogeneous dispersion simply by mixing, maintaining formulation simplicity while ensuring consistent application performance through uniform oil distribution

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If encapsulation techniques are used to isolate oil from aqueous phase, then the formulation stability is improved, but the device complexity increases

Engineering Contradiction:

Improveformulation stabilityVSAvoidencapsulation process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention achieves encapsulation by changing the chemical parameters of the polymer structure rather than requiring complex physical encapsulation devices or multi-step processes. By selecting a polymer with specific hydrophobic-hydrophilic balance and molecular weight, stable oil encapsulation is achieved through simple mixing, thereby improving formulation stability without increasing device or process complexity

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 method effectively encapsulates oil molecules in high concentrations, up to 60% by weight, within the aqueous formulation, ensuring stability and improved performance in various applications by trapping oil molecules within solvation cages, allowing for flexible formulation and wide compatibility with different oil types.

Implementation Method 1

an associative polymer consisting of: at least one monomer which is (meth)acrylic acid, at least one monomer which is a (meth)acrylic ester, and at least one associative hydrophobic monomer

Methodology Applied

Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 2

adjusting the pH of the mixture obtained in step a) to a value greater than 6... precipitate the mixture obtained after step b) by adjusting the pH to a value less than 6

Methodology Applied

Scientific EffectpH-induced precipitation: Precipitation

Data Source

PatentEP2237865B1Method for encapsulating oils in an aqueous medium with hase polymer emulsions, products obtained and uses thereof

Publication Date: 2019.03.20 COATEX SA

AI summary

The invention relates to a method for producing an aqueous formulation containing at least one oil, that comprises the steps of mixing at least one associative polymer, oil and water, encapsulating the oil by raising the pH to a value higher than 8, optionally precipitating the mixture by lowering the pH to a value lower than 6, and optionally isolating the particles thus obtained by water removal. The invention also relates to aqueous formulations and aqueous dispersions as well as to the solid particles thus obtained.