Silicate Shell Microcapsules Density Matching Temperature Release
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Solution Overview
Problem
Silicate shell microcapsules used in delivery technologies often settle due to density differences, leading to formulation issues, and lack a temperature-based release mechanism, which is necessary for certain applications like coatings and adhesives.
Innovation Solution
The development of an aqueous suspension of silicate shell microcapsules with a core containing a burst aid, where the burst aid is added to the oil phase before encapsulation, allowing for temperature-controlled release by matching the density of the external phase and using volatile hydrocarbons or siloxanes to facilitate release at specific temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicate shell microcapsules are used in suspension, then encapsulation and delivery of actives is achieved, but the microcapsules settle upon storing due to density differences
Solution Approach 1:
The patent modifies the density parameter of the microcapsule system by incorporating a burst aid into the core that matches the density of the external aqueous phase. This density adjustment prevents gravitational settling and maintains suspension uniformity during storage, directly resolving the contradiction between achieving encapsulation and preventing settlement.
Solution Approach 2:
The patent creates a composite microcapsule structure consisting of a silicate shell, an organic core containing the active, and a burst aid component. This multi-component composite design allows the burst aid to counterbalance the high density of the silicate shell, enabling the overall microcapsule to match the density of the external phase and remain stable in suspension.
2Adaptability or versatility
If conventional silicate shell microcapsules are used, then encapsulation is achieved, but they lack a temperature-based release mechanism needed for certain applications
Solution Approach 1:
The patent utilizes the phase transition properties of the burst aid, which has a specific vapor pressure that causes it to evaporate at a predetermined temperature. This phase transition from liquid to vapor creates internal pressure that ruptures the silicate shell, enabling temperature-controlled release of the active. This mechanism provides the needed adaptability for coatings and adhesives while ensuring reliable performance.
Solution Approach 2:
The patent replaces conventional mechanical or chemical release mechanisms with a vapor pressure-driven release system. The burst aid's vapor pressure acts as a mechanical force that systematically ruptures the shell at a specific temperature, providing a reliable and predictable release mechanism suitable for industrial applications.
3Strength
If the density of microcapsules is increased with silicate shell material, then encapsulation strength is improved, but settling upon storing is accelerated
Solution Approach 1:
The patent adjusts the effective density parameter of the microcapsule by incorporating the burst aid, which compensates for the high density of the silicate shell. This parameter modification maintains the structural strength provided by the silicate shell while reducing the settling rate to an acceptable level, resolving the contradiction between strength and settling speed.
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 approach creates stable microcapsules that prevent settling and enable quick, temperature-dependent release of actives, enhancing the usability of silicate shell microcapsules in formulations by ensuring consistent delivery and application performance.
Implementation Method 1
the level of burst aid could be regulated to essentially match the density of the external aqueous phase of the formulation which would also provides quick release of the actives at reduced temperatures, dependant on the vapor pressure of the burst aid
Implementation Method 2
volatile hydrophobic hydrocarbon or a volatile siloxane with an aqueous solution of a cationic surfactant to form an oil in water emulsion
Implementation Method 3
polymerizing the tetraalkoxysilane at the oil/water interface of the emulsion to form a microcapsule having a core containing the oil and a silicate shell
Implementation Method 4
mixing an oil phase containing a burst aid that is a volatile hydrophobic hydrocarbon or a volatile siloxane with an aqueous solution of a cationic surfactant to form an oil in water emulsion
Data Source
AI summary
Aqueous suspensions of silicate shell microcapsules are disclosed having a core containing a burst aid wherein the silicate shell microcapsules are obtained by; I) mixing an oil phase containing a burst aid and an aqueous solution of a cationic surfactant to form an oil in water emulsion, II) adding a water reactive silicon compound comprising a tetraalkoxysilane to the oil in water emulsion, III) polymerizing the tetraalkoxysilane at the oil/water interface of the emulsion to form a microcapsule having a core containing the oil and a silicate shell.