Microfibrillated Cellulose Brush-Like Fibrils High-Pressure Homogenization
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Solution Overview
Problem
Conventional microfibrillated cellulose (MFC) exhibits limitations in water retention and zero shear viscosity, particularly in solvents like polyethylene glycol (PEG), which affects its performance in high-performance applications such as coatings, paints, adhesives, and pharmaceuticals.
Innovation Solution
A process involving mechanical pretreatment and high-pressure homogenization with a pressure drop of at least 1000 bar, resulting in fibrils with 'brush-like' end structures and increased surface area, enhances water retention and rheological properties by forming a more stable three-dimensional network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional homogenization methods are used to produce microfibrillated cellulose, then the production process is simple, but the water retention properties and zero shear viscosity are limited
Solution Approach 1:
The patent applies parameter changes by operating the homogenizer at extremely high pressures (1000-3000 bar) and high temperatures (50-150°C), transforming the conventional low-pressure homogenization process. These parameter changes enable the formation of brush-like end structures on fibrils, which significantly improve water retention properties and zero shear viscosity while maintaining a relatively simple device structure.
Solution Approach 2:
The patent employs periodic action through cyclic homogenization processes where the homogenizer operates in alternating high-pressure/high-temperature and ambient conditions. This periodic treatment over multiple cycles creates the characteristic brush-like morphology on fibril ends, progressively improving water retention and rheological properties without requiring complex continuous processing systems.
2Reliability
If conventional homogenization is used, then the device structure is simple, but the zero shear viscosity and water holding capacity are insufficient for high-performance applications
Solution Approach 1:
The patent utilizes extreme parameter changes by subjecting the cellulose suspension to homogenization at pressures exceeding 1000 bar and temperatures above 50°C. These harsh conditions induce structural changes in the fibrils, creating brush-like end structures that dramatically increase zero shear viscosity and water holding capacity. The device remains relatively simple, avoiding complex multi-stage systems.
Solution Approach 2:
The patent replaces conventional gentle mechanical homogenization with a combination of high-pressure hydraulic action and thermal energy. This substitution of mechanical systems with pressure and heat-driven mechanisms enables the formation of desirable fibril morphology and network structures that enhance rheological properties without requiring increasingly complex mechanical equipment.
3Reliability
If high pressure homogenization with brush-like end structures is achieved, then water retention and rheological properties are improved, but the energy consumption increases
Solution Approach 1:
The patent employs periodic homogenization cycles where high energy input during active homogenization is followed by recovery periods. This periodic operation allows the system to achieve brush-like fibril morphology through repeated cycles of high-pressure/temperature treatment, distributing the energy consumption over time rather than requiring continuous extreme energy input, thereby improving water retention while managing energy usage.
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 modified MFC demonstrates improved water retention and increased zero shear viscosity, achieving higher water holding capacity and stability in gel-like dispersions, particularly in PEG, compared to conventional methods.
Implementation Method 1
subjecting the cellulose pulp to a pressure drop, by expanding the cellulose through at least one orifice, providing a pressure drop between a volume segment, preferably a chamber, that is located upstream of said orifice, and another volume segment, preferably a chamber, that is located downstream of said orifice
Implementation Method 2
the cellulose fibrils are subjected to a turbulent flow regime in said volume segment, preferably a chamber, that is located downstream of said orifice
Data Source
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AI summary
The present invention relates to microfibrillated cellulose ("MFC"), in particular to microfibrillated cellulose, which is morphologically different from conventional MFC known in the art and/or which provides improved water retention properties and/or improved rheological properties, in particular increased zero shear viscosity, η0, (also known as: "viscosity at rest", i.e. viscosity in the absence of shear forces), in solution, in particular in polyethylene glycol (PEG) as solvent, vis-à-vis conventional MFC as known in the art.