Dry Granulation of Nanoparticles via Continuous Container Rotation
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Solution Overview
Problem
Current granulation processes for nanoparticles are complex, often require solvents and organic binders, leading to residual solvent content and inadequate mechanical properties in the granules, making them either too friable or hard, and are not suitable for dry process material development.
Innovation Solution
A dry granulation process involving the continuous rotation of a container with inorganic nanoparticles at a constant speed, allowing the particles to roll on the interior wall without the addition of a humidifier or organic binder, resulting in micrometric or millimetric granules with improved mechanical properties and flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dry granulation by compaction/crushing is used, then granule mechanical resistance is improved, but device complexity increases due to specially designed parts to withstand mechanical stresses
Solution Approach 1:
The patent replaces complex mechanical compaction systems with a simple rotating container system. Instead of using specially designed parts to withstand high mechanical stresses during compaction, the invention uses continuous rotation to create gentle tumbling motion that allows particles to compact naturally through their own weight and friction, eliminating the need for complex pressure application mechanisms.
Solution Approach 2:
The granulation process utilizes the self-weight and self-friction of the particles themselves to achieve compaction, rather than requiring external mechanical force. The rotating container creates conditions where particles naturally compact through their own properties, eliminating the need for externally applied mechanical stress and complex device structures.
2Ease of manufacture
If wet granulation with solvents and binders is used, then granule formation is improved, but residual solvent content increases and purity decreases
Solution Approach 1:
The invention completely removes solvents and organic binders from the granulation process. By using dry granulation through continuous rotation, the process achieves effective granule formation without any liquid phase, thereby eliminating residual solvent content and maintaining complete purity of the granulated material.
Solution Approach 2:
The patent changes the fundamental parameter of the granulation process from wet to dry conditions. Instead of using liquid solvents and binders to facilitate granule formation, the invention uses mechanical energy from rotation and natural particle interactions under dry conditions to achieve the same granulation effect without any residual chemical contaminants.
3Ease of manufacture
If wet granulation is used, then granule formation is improved, but handling difficulty increases due to friability or excessive hardness
Solution Approach 1:
The patent replaces wet chemical binding mechanisms with mechanical tumbling and friction-based compaction. This substitution produces granules with optimal mechanical properties that are neither too friable nor too hard, as the gentle rotational forces and natural particle friction create balanced granule structures that are easy to handle and transport.
4Ease of manufacture
If spray drying or freeze drying is used, then granulation is improved, but process complexity increases due to temperature and solvent management
Solution Approach 1:
The invention extracts and eliminates the complex temperature control and solvent management systems required by spray drying and freeze drying processes. By using simple continuous rotation in ambient conditions, the process achieves effective granulation without any phase change requirements, eliminating the need for complex thermal and chemical control systems.
5Adaptability or versatility
If nanoparticles are stored as loose powder, then storage flexibility is improved, but safety risk increases due to explosion risk from surface reactivity
Solution Approach 1:
The patent nests nanoparticles within granule structures, where individual nanoparticles are contained within larger granule matrices. This nesting approach maintains the flexibility of powder storage while significantly reducing explosion risk, as the granule structure limits the surface area exposed to oxygen and prevents the propagation of potential explosions.
6Ease of operation
If nanoparticles are suspended in liquid, then handling is improved, but storage volume increases due to larger mass requirement
Solution Approach 1:
The patent changes the physical state of the nanoparticle formulation from liquid suspension to dry granulated powder. This parameter change eliminates the need for large volumes of liquid solvent while maintaining good handling properties, as the granulated powder provides free-flowing characteristics similar to suspensions but with concentrated active material and minimal storage volume.
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 produces granules with increased apparent density, spherical shape, and adjustable size distribution, retaining specific surface area and allowing easy dispersion in solvents, while simplifying handling and storage, and reducing storage volume.
Implementation Method 1
setting in motion all of the particles along said interior wall by rotating the container along an axis of rotation passing through said container
Implementation Method 2
the particles move relative to the interior wall of the container and 'roll' on this wall
Implementation Method 3
forming granules of micrometric sizes by agglomeration of the nanoparticles together
Data Source
Figure 1~2c
Figure 3a~5b
Figure 5c~7b
AI summary
The invention relates to a method for forming micrometric or millimetric granules by means of agglomeration of nanometric particles. According to the invention, a group of nanometric particles is introduced into a container including an inner wall having a circular or substantially circular cross-section and the group of particles is moved along the inner wall by rotating the container about a rotation axis transverse to the container. The particles are moved under dry conditions and the container is rotated continuously at a constant speed for multiple consecutive hours. The invention also relates to a micrometric or millimetric granule of an inorganic material formed only by nanometric particles of the inorganic material, said particles being agglomerated with one another.