Core-Shell Silica Surface Chemistry for Higher Metal Ion Loading

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Solution Overview

Problem

Conventional core shell silica particles exhibit low capacity and loading of metal ions, limiting the delivery of active and/or benefit agents to the oral cavity, raising regulatory concerns and consumer aversion.

Innovation Solution

A method for preparing high loading core shell silica particles by etching silica with a monovalent metal ion and then reacting it with a divalent metal ion in an acidic aqueous solution containing a humectant, resulting in CSS particles with increased surface active silicate groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional core shell silica particles are used to deliver active agents, then the oral care composition can provide additional desired properties, but the capacity and loading of metal ions is low, limiting delivery effectiveness

Engineering Contradiction:
Improvemetal ion loading capacityVSAvoiddelivery effectiveness
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the silica particle surface by introducing metal silicate layers (such as zinc silicate, calcium silicate) through controlled chemical reactions. This modifies the surface charge density and ion exchange capacity, enabling higher metal ion loading capacity while maintaining reliable delivery to oral surfaces.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite core-shell silica particles with metal silicate surface layers. The core silica provides structural support and the shell metal silicate layer provides enhanced ion exchange capacity and metal ion binding, resulting in a composite material with superior delivery effectiveness compared to pure silica particles.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If multiple active and/or benefit agents are included in oral care compositions, then desired properties are provided, but regulatory concerns increase, consumer aversion increases, and incompatibility with other components increases

Engineering Contradiction:
Improvefunctional properties of oral care compositionVSAvoidcomplexity of oral care composition
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates multi-functional core-shell silica particles that can deliver multiple active agents (such as zinc ions for antibacterial activity, calcium ions for remineralization) simultaneously. This single composite particle system replaces the need for multiple separate active agents, reducing formulation complexity while maintaining versatile functional properties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs a nested structure where metal ions are embedded within the metal silicate shell layer of the core-shell silica particles. This nested arrangement allows multiple active agents to be contained and delivered in a organized, space-efficient manner, reducing the overall complexity of the oral care composition while providing multiple benefits.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 produces CSS particles with enhanced charge density and ion exchange capacity, enabling improved delivery of metal ions like Zn2+ for antibacterial and anti-malodor properties in oral care compositions.

Implementation Method 1

contacting silica particles with a base comprising a first metal ion to produce core shell silica particles, each of the core shell silica particles comprising a silica core and a silicate of the first metal ion etched on a surface of the silica core

Methodology Applied
Scientific EffectEtching:

Implementation Method 2

contacting each of the core shell silica particles comprising the silicate of the first metal ion with an acidic aqueous solution comprising a metal salt having a second metal ion, wherein the second metal ion is a divalent ion, to produce core shell silica particles comprising the silica core and a silicate of the second metal ion on the surface of the silica core

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP3661477B1Core-shell silica and method for producing same
Publication Date: 2026.03.18 COLGATE PALMOLIVE CO
  • EP3661477B1 patent drawingFigure 1

AI summary

Methods for preparing high loading core shell silica (CSS) particles, or CSS particles having a relatively greater amount of surface active silicate groups than CSS particles prepared according to conventional methods is provided. The method may include contacting silica particles with a base having a first metal ion to produce core shell silica particles. Each of the core shell silica particles may include a silica core and a silicate of the first metal ion etched on a surface of the silica core. The method may also include contacting each of the core shell silica particles having the silicate of the first metal ion with an acidic aqueous solution including a metal salt having a second metal ion to produce core shell silica particles including the silica core and a silicate of the second metal ion on the surface of the silica core.