Silicate Shell Microcapsules for Controlled Release
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Solution Overview
Problem
Existing encapsulation methods for active materials like fabric and hair conditioners often result in either no diffusion or leaching, which is undesirable, and there is a need for controlled or prolonged release to achieve effective conditioning and treatment of textiles with hydrophobicity and flame retardant properties.
Innovation Solution
The use of a water reactive silicon compound comprising tetraalkoxysilane and an alkoxysilane with an amino or quaternary ammonium substituted alkyl group in the production of silicate shell microcapsules, which allows for controlled release by condensing and polymerizing at the interface of the emulsion droplets, forming a shell that permits controlled diffusion or leaching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water reactive silicon compound is added to an oil in water emulsion to form a shell, then the shell provides encapsulation and controlled release, but the shell thickness and composition must be precisely controlled to achieve desired diffusion rates
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition ratios of tetraalkoxysilane to alkoxysilane (from 1:4 to 4:1), water content (0-50 wt%), and pH levels (3-10) to control shell thickness and porosity. These parameter adjustments enable precise control over the diffusion rate of active materials while maintaining reliable encapsulation performance.
Solution Approach 2:
The patent uses composite materials by combining tetraalkoxysilane and alkoxysilane in various ratios to form a composite silicate shell. This composite structure allows tuning of shell properties such as thickness, density, and porosity, thereby controlling the release kinetics of encapsulated active materials while ensuring structural integrity.
2Reliability
If the shell is made more impermeable to prevent leaching of sunscreen, then UV protection is maintained, but other active materials like fabric conditioners cannot diffuse out effectively
Solution Approach 1:
The patent applies local quality by creating shells with spatially varying properties through controlled phase separation during formation. The shell exhibits different local densities and porosity regions, allowing selective permeability: dense regions prevent leaching of hydrophobic materials like sunscreen, while more porous regions enable diffusion of hydrophilic active materials such as fabric conditioners.
Solution Approach 2:
The patent utilizes porous materials by forming silicate shells with controlled porosity through the interaction of tetraalkoxysilane and alkoxysilane. The pore size and distribution are adjusted by varying composition ratios and processing conditions, enabling the shell to act as a selective barrier that maintains UV protection while allowing controlled release of different active materials based on their molecular characteristics.
3Stability of the object's composition
If conventional encapsulation methods are used for fabric conditioners, then the conditioner is protected from washing off, but the conditioner cannot diffuse out to provide effective conditioning
Solution Approach 1:
The patent applies parameter changes by adjusting the silicate shell composition (tetraalkoxysilane to alkoxysilane ratio from 1:4 to 4:1) and formation conditions (pH 3-10, water content 0-50 wt%) to create shells with optimized porosity. This enables the shell to retain fabric conditioner on the microcapsule surface while allowing controlled diffusion to the fabric, preventing wash-off while maintaining conditioning effectiveness.
4Ease of manufacture
If the shell formation process is simplified by using a single silicon compound, then manufacturing is easier, but controlled release performance is insufficient
Solution Approach 1:
The patent merges two silicon compounds (tetraalkoxysilane and alkoxysilane) into a single shell formation process. This combination allows the system to achieve both ease of manufacture (single-step process) and reliable controlled release performance (tunable porosity and thickness) by optimizing the ratio and interaction of the two compounds during emulsion formation and drying.
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 effectively encapsulates oil phases, allowing for controlled or prolonged release of conditioning agents and textile treatments, improving retention on fabrics and providing sustained benefits such as softness and flame retardancy.
Implementation Method 1
adding a water reactive silicon compound to an oil in water emulsion, thereby condensing and polymerizing the water reactive silicon compound to form silicate shell microcapsules
Implementation Method 2
condensing and polymerizing the water reactive silicon compound to form silicate shell microcapsules
Implementation Method 3
allowing for controlled diffusion or leaching of the oil phase
Data Source
AI summary
A process for preparing silicate shell microcapsules comprises adding a water reactive silicon compound to an oil in water emulsion, thereby condensing and polymerizing the water reactive silicon compound to form silicate shell microcapsules having a core comprising the oil phase of the said emulsion. The water reactive silicon compound comprises a tetraalkoxysilane and an alkoxysilane having an amino or quaternary ammonium substituted alkyl group.