Double Emulsion Microcapsules for Volatile Compound Retention

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Solution Overview

Problem

Current methods for encapsulating volatile compounds in formulated products, such as perfumes, fail to provide effective protection against evaporation and degradation, leading to short-lived odorous properties due to rapid diffusion and susceptibility to environmental interactions like hydrolysis, thermal denaturation, or oxidation.

Innovation Solution

A method involving the creation of double emulsion technology to produce size-controlled solid microcapsules with a crosslinked polymer shell, where volatile compounds are encapsulated within a core containing hydrophobic particles, effectively limiting diffusion and degradation by using specific temperature and viscosity conditions during the emulsion formation and polymerization process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional encapsulation methods (spray-drying, interfacial polymerization, solvent evaporation) are used, then capsules are formed to protect volatile compounds, but the diffusion time of volatile compounds through the capsule-forming materials remains very short resulting in very rapid leakage

Engineering Contradiction:
Improveprotection and retention properties of volatile compoundsVSAvoiddiffusion time of volatile compounds through capsule-forming materials
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent employs a double emulsion structure where an inner emulsion (containing volatile compounds in an inner phase) is nested within an outer emulsion (with polymer-forming outer phase). This nested configuration creates multiple diffusion barriers, significantly extending the diffusion time and improving retention of volatile compounds compared to conventional single-layer capsules.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The capsule wall is formed as a composite structure resulting from the double emulsion process, combining inner and outer phases with different properties. This composite structure provides superior barrier performance against volatile compound diffusion while maintaining structural integrity, resolving the contradiction between protection and retention.

Inventive Principle:
Principle #40Composite materials

2Duration of action of stationary object

If volatile compounds are encapsulated to prevent degradation from environmental interactions, then the lifetime of odorous properties is extended, but rapid evaporation still occurs due to insufficient barrier properties

Engineering Contradiction:
Improvelifetime of odorous propertiesVSAvoidevaporation of volatile compounds
Core Design Contradiction:
Duration of action of stationary objectVSLoss of substance

Solution Approach 1:

The double emulsion nested structure creates multiple containment layers that act as sequential barriers to evaporation. The inner phase encapsulates volatile compounds, while the outer phase provides an additional barrier, significantly reducing evaporation rates and extending the lifetime of odorous properties.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The capsule walls formed from the double emulsion process create flexible yet effective barrier films that prevent volatile compound evaporation while allowing for practical application in formulated products. The thin film structure maintains effectiveness without requiring excessive material thickness.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If capsules are made with improved protection properties to prevent degradation, then retention capacity is enhanced, but the manufacturing complexity increases with double emulsion technology

Engineering Contradiction:
Improveretention capacity of volatile compoundsVSAvoidcomplexity of encapsulation method
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The encapsulation process is segmented into distinct stages: formation of the inner emulsion containing volatile compounds, followed by formation of the outer emulsion, and finally polymerization. This segmentation allows each stage to be optimized independently while maintaining overall simplicity and achieving superior retention capacity.

Inventive Principle:
Principle #1Segmentation

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 method results in microcapsules that significantly extend the retention of volatile compounds, providing a stable and long-lasting fragrance by preventing evaporation and protecting against degradative chemical species, thus enhancing the performance and longevity of perfumed products.

Implementation Method 1

Because of their volatile nature, these compounds evaporate rapidly from the formulated product that contains them

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

The diffusion time of volatile compounds through the capsule-forming materials made through most of these methods remains very short

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

the polymerisation of the composition C2, whereby solid microcapsules dispersed in the composition C3 are obtained

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS11234911B2Method for producing capsules comprising at least one volatile compound, and resulting capsules
Publication Date: 2022.02.01 CAPSUM

AI summary

The present invention relates to a process for preparing solid microcapsules comprising the following steps:a) preparation of a composition C1, which is either a composition C1a, comprising a single hydrophobic solid particle, or a composition C1b comprising a plurality of hydrophobic solid particles dispersed in a hydrophilic phase,b) addition with stirring of the composition C1 in a polymeric composition C2 at a temperature Tb, whereby an emulsion (E1) is obtained;c) addition, with stirring, of the emulsion (E1) in a composition C3 at a temperature Tc, whereby a double emulsion (E2) is obtained;d) applying a shear to the emulsion (E2), whereby a double emulsion (E3) is obtained; ande) polymerization of the composition C2, whereby solid microcapsules dispersed in the composition C3 are obtained.