Surface-Reacted Calcium Carbonate Microcapsule Template

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Solution Overview

Problem

Conventional methods for encapsulating active ingredients in microcapsules often result in large particles and low loading capacities, with existing templates unable to load high amounts of active ingredients and requiring harsh conditions for carrier removal.

Innovation Solution

A process involving surface-reacted calcium carbonate as a template, where the calcium carbonate is treated with carbon dioxide and H+ ion donors to create a porous structure, which is then loaded with active ingredients and encapsulated with a multilayer shell using layer-by-layer assembly, allowing for high loading capacities and mild template removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional encapsulation methods (pan coating, centrifugal extrusion, hot melt extrusion, spray-drying, coacervation-phase separation, ionotropic gelation, interfacial polycondensation, or matrix polymerization) are used, then the encapsulation process can be performed, but the particles become comparatively large and the loading capacity is low

Engineering Contradiction:

Improveparticle size controlVSAvoidactive ingredient loading

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent employs porous calcium carbonate particles as templates for encapsulation. The porous structure provides high surface area and volume for active ingredient loading, enabling high loading capacities (up to 50 wt.-%) while maintaining small particle sizes through the inherent pore structure of the calcium carbonate template.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent implements a nested structure where the active ingredient is loaded into the porous calcium carbonate template, which is then encapsulated by a polymeric shell. This nested configuration allows the active ingredient to be protected within the shell while maintaining high loading capacity through the porous template structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Quantity of substance

If conventional templates are used for high active ingredient loading, then higher amounts of active ingredient can be loaded, but the template cannot be removed under mild conditions

Engineering Contradiction:

Improveactive ingredient loadingVSAvoidtemplate removal condition

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent utilizes the pH-dependent solubility of calcium carbonate as a parameter change mechanism for template removal. The calcium carbonate template is dissolved by treatment with acid (e.g., hydrochloric acid), transforming it from an insoluble solid to soluble calcium ions, thereby removing the template under mild conditions while preserving the high loading capacity achieved during the encapsulation process.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If layer-by-layer encapsulation is used with emulsion droplets or solid carriers, then small encapsulated particles can be obtained, but the loading of active ingredient remains low

Engineering Contradiction:

Improveparticle sizeVSAvoidactive ingredient loading

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent replaces conventional solid carriers with porous calcium carbonate particles that have high porosity and surface area. This porous structure provides extensive sites for active ingredient adsorption and absorption, enabling high loading capacities (up to 50 wt.-%) while maintaining small particle sizes through the controlled pore structure of the calcium carbonate template.

Inventive Principle:

Principle #31Porous materials

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 process enables the production of microcapsules with high active ingredient loading (up to 50 wt.-%) and controlled release, while allowing for the removal of the template under mild conditions, overcoming the limitations of conventional methods.

Implementation Method 1

surface-reacted calcium carbonate is a reaction product of natural ground calcium carbonate or precipitated calcium carbonate with carbon dioxide and one or more H3O+ ion donors

Methodology Applied

Scientific EffectSurface reaction: Chemical Bonding

Implementation Method 2

at least one active compound is adsorbed in porous organic or inorganic templates

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

encasing the loaded surface-reacted calcium carbonate with a multilayer shell by consecutively depositing at least two complementary layers using layer-by-layer assembly

Methodology Applied

Scientific EffectLayer-by-layer assembly: Self-Assembly

Data Source

PatentUS20230201126A1Surface-reacted calcium carbonate in a process for the production of a loaded microcapsule

Publication Date: 2023.06.29 OMYA INT AG

AI summary

The present invention relates to a process for the production of a microcapsule comprising an active ingredient or inactive precursor thereof, as well as a microcapsule obtainable thereby. The process involves the use of a surface-reacted calcium carbonate as a template for encapsulating the active ingredient or inactive precursor thereof. The active ingredient or inactive precursor thereof is loaded onto the surface-reacted calcium carbonate and subsequently encased by a multilayer shell comprising at least two complementary layers using layer-by-layer assembly. Further aspects of the invention relate to the use of a surface-reacted calcium carbonate as a template for encapsulating the active ingredient or inactive precursor thereof, a product comprising said microcapsule, as well as the use of said microcapsule.