Two-Stage ALD Coating for Stable Organic Particles
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Solution Overview
Problem
Existing encapsulation methods, such as atomic layer deposition (ALD), are limited in applicability to a narrow range of compounds, often causing degradation and agglomeration of particles, making them unsuitable for industrial-scale production of coated organic particles.
Innovation Solution
A process involving sequential contact of organic particles with metal- or semimetal-containing compounds and decomposition compounds in controlled temperature stages, maintaining particle motion and using specific temperature differences to prevent agglomeration and ensure uniform coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition is used to encapsulate organic compounds, then uniform and thin coating is achieved, but most compounds are destroyed and/or agglomerated
Solution Approach 1:
The patent applies parameter changes by conducting ALD at two different temperature stages: a first temperature (e.g., 50-150°C) for initial coating cycles, and a second temperature at least 20°C higher (e.g., 70-200°C) for subsequent cycles. This temperature variation optimizes both coating uniformity and compound stability, preventing destruction and agglomeration while achieving precise encapsulation.
2Ease of manufacture
If harsh coating conditions are applied, then coating process is robust, but only very stable compounds like paracetamol can be coated without significant degradation
Solution Approach 1:
The patent uses parameter changes by implementing a two-stage temperature process that adapts to different compound stabilities. The lower first temperature protects sensitive compounds, while the higher second temperature provides robust coating conditions, enabling the process to handle a wide range of compounds from stable to sensitive.
Solution Approach 2:
The patent applies dynamics by making the coating process adaptive through sequential temperature adjustment. The process dynamically transitions from a protective low-temperature stage to a robust high-temperature stage, allowing it to accommodate various compound stabilities while maintaining manufacturing robustness.
3Reliability
If particles are coated by conventional ALD, then encapsulation is achieved, but particles tend to agglomerate requiring repeated deagglomeration which is hardly feasible on industrial scale
Solution Approach 1:
The patent resolves the agglomeration issue through parameter changes by using a two-stage temperature approach. The controlled temperature progression prevents particle agglomeration during coating, eliminating the need for repeated deagglomeration steps and enabling industrial-scale production while maintaining effective encapsulation.
4Device complexity
If a single temperature is used for ALD coating, then process is simple, but compound degradation and agglomeration occur
Solution Approach 1:
The patent applies parameter changes by implementing a two-stage temperature process that improves compound integrity while maintaining reasonable process complexity. The first temperature stage protects against degradation, and the second stage ensures proper coating formation, achieving reliable results without excessive complexity.
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 allows for a wide range of compounds to be coated without significant degradation, achieving uniform thickness and preventing particle agglomeration, suitable for industrial-scale production.
Implementation Method 1
sequentially contacting the organic particles with a metal- or semimetal-containing compound and a decomposition compound in the gaseous state at a first temperature, and sequentially contacting the organic particles with a metal- or semimetal-containing compound and a decomposition compound in the gaseous state at a second temperature
Data Source
AI summary
The present invention is in the field of coated organic particles, in particular comprising small molecules, by using atomic layer deposition. It relates to a process for preparing coated organic particles comprising the steps in the following order: (a) bringing particles containing an organic compound in motion to each other, (b) sequentially contacting the organic particles with a metal- or semimetal-containing compound and a decomposition compound in the gaseous state at a first temperature, and (c) sequentially contacting the organic particles with a metal- or semimetal-containing compound and a decomposition compound in the gaseous state at a second temperature, wherein the second temperature is at least 20° C. above the first temperature. Shell, in particular the density of the inner part of the shell is 5% lower than the density of the outer part of the shell.