Microcapsule Fragrance Release via Layered Polymer Shells

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Solution Overview

Problem

Existing laundry products fail to effectively release fragrance when clothes are taken out of the washing machine, as fragrance is washed away during the rinse cycle without encapsulation.

Innovation Solution

Development of microcapsules containing a benefit agent within a water-insoluble porous inner shell, coated with layers of cationic and anionic polymers, including anionically modified polysaccharides, which release the fragrance during the washing or conditioning process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If fragrance is added into detergents without encapsulation, then fragrance is present in the laundry composition, but fragrance is washed away during the rinse cycle

Engineering Contradiction:
Improvefragrance presenceVSAvoidfragrance loss during rinse
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The fragrance is segmented into individual microcapsule units, each containing a benefit agent core surrounded by porous shell layers. This segmentation allows the fragrance to be distributed as discrete particles throughout the laundry composition, enabling controlled release at the fabric surface rather than being washed away as a bulk solution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microcapsule structure employs a nested doll configuration with multiple concentric layers: an inner porous shell containing the benefit agent, surrounded by an outer porous shell with cationic and anionic polymer layers. This nested structure protects the fragrance while enabling staged release mechanisms.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 3:

The microcapsule employs flexible porous shell structures made of polymer layers that can deform and rupture under mechanical stress. The outer shell consists of cationic and anionic polymer layers that provide both structural integrity and controlled permeability, allowing the fragrance to be released when the shell breaks during the consumer dressing process.

Inventive Principle:
Principle #30Flexible shells and thin films

2Duration of action of moving object

If microcapsules are designed to release fragrance during washing, then fragrance release is achieved, but fragrance must remain encapsulated during storage and application

Engineering Contradiction:
Improvefragrance release timingVSAvoidencapsulation stability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The microcapsule system transitions from a static encapsulated state during storage and application to a dynamic release state during consumer use. The porous shell structure remains intact and stable under normal handling conditions, but is designed to rupture dynamically when subjected to the mechanical pressure and rubbing forces applied during the consumer dressing process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The microcapsule exploits parameter changes in the shell material properties under different conditions. The cationic and anionic polymer layers maintain stable structural parameters during storage, but undergo structural changes when exposed to the mechanical stress of application, transitioning from a closed encapsulated state to an open release state.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If multiple polymer layers are formed without separation steps, then manufacturing process is simplified, but layer formation precision must be maintained

Engineering Contradiction:
Improveprocess simplicityVSAvoidlayer formation control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The manufacturing process merges the formation of multiple polymer layers into a single continuous operation without intermediate separation steps. The cationic and anionic polymer layers are deposited sequentially in the same reaction vessel, allowing the process to be simplified while maintaining layer integrity through electrostatic attraction between oppositely charged polymers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The alternating cationic and anionic polymer layers form through self-service mechanisms where each layer automatically attracts and binds the oppositely charged subsequent layer. This electrostatic self-assembly process maintains manufacturing precision without requiring external intervention or separation steps between layer formations.

Inventive Principle:
Principle #25Self-service

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 microcapsules ensure sustained fragrance release during the washing process and improved perfume delivery to fabrics, enhancing the consumer experience by maintaining fragrance intensity on clothes.

Implementation Method 1

an outer shell comprising at least one layer of cationic polymer and at least one layer of anionic polymer

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

the benefit agent is capable of being released by action of diluting the laundry composition

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3414313B1microcapsule
Publication Date: 2020.05.27 UNILEVER NV

AI summary

Disclosed is a microcapsule comprising a benefit agent inside a water insoluble porous inner shell, an outer shell comprising at least one layer of cationic polymer and at least one layer of anionic polymer, wherein the anionic polymer is anionically modified polysaccharide, and optionally the microcapsule comprises a non-ionic polysaccharide deposition aid.