Anionic Cellulose Fibrillation via Homogenization
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Solution Overview
Problem
Current methods for producing fibril cellulose from wood fibers face challenges such as low productivity due to high energy input and susceptibility to clogging in homogenizers, especially when processing fibers with normal sizes.
Innovation Solution
A method involving pre-disintegrating wood fiber pulp of anionic cellulose in a disperser, followed by homogenization at pressures of 300 to 650 bar with 2 to 4 passes through a narrow gap, achieving a Brookfield viscosity exceeding 10,000 mPa·s, while maintaining a consistency of 2 to 3 wt-% to optimize fibrillation without clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high input power is applied to achieve good fibrillation, then the degree of fibrillation is improved, but productivity decreases
Solution Approach 1:
The patent applies preliminary chemical modification to the cellulose fibers before mechanical homogenization. Specifically, the cellulose is carboxymethylated and then anionicized (e.g., through oxidation or cation exchange) to reduce inter-fibril bonding strength. This preliminary chemical action weakens the fiber structure, making it easier to fibrillate mechanically, thereby achieving good fibrillation at lower mechanical energy input and maintaining productivity
2Manufacturing precision
If homogenizer pressure is increased to improve fibrillation, then fibrillation quality improves, but susceptibility to clogging increases
Solution Approach 1:
The patent performs preliminary chemical treatment (carboxymethylation and anionicization) to reduce bonding between cellulose fibrils. This preliminary action prevents aggregation and clogging during homogenization, allowing the use of moderate pressure (300-650 bar) to achieve good fibrillation without increasing clogging susceptibility
Solution Approach 2:
The patent changes the chemical parameters of the cellulose by introducing anionic groups, which alter the physical-chemical properties of the fiber suspension. This parameter change reduces inter-fibril attraction and improves flow characteristics, enabling homogenization at optimal pressure levels that balance fibrillation quality and clogging prevention
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 method enhances the fibrillation of cellulose while maintaining high productivity and preventing homogenizer clogging, resulting in a high-quality fibril cellulose product with improved internal bond strength and tensile strength for paper products.
Implementation Method 1
homogenizing said pre-disintegrated fibre pulp in the homogenizer wherein it is passed through a narrow through-flow gap, wherein the homogenization pressure is the pressure developed in the pre-disintegrated fibre pulp before the gap due to the resistance caused by the gap, at a pressure of 300 to 650 bar
Implementation Method 2
passing the suspension under high pressure repeatedly through a narrow gap where it achieves a high velocity, after which it impinges on an impact surface that decelerates the velocity
Implementation Method 3
pre-disintegrating wood fibre pulp of anionic cellulose, which is carboxymethylated cellulose, in a disperser
Data Source
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AI summary
A method for fibrillation of cellulose comprises the following steps: - introducing fibre pulp of anionic cellulose at a consistency of 1 to 4% into a homogenizer, and - homogenizing said fibre pulp in the homogenizer at a pressure of 200 to 1000 bar, advantageously 300 to 650 bar, and by using 2 to 4 passes through for the same fibre pulp under these conditions, and - after said passes through, taking pulp from the homogenizer, which pulp has been fibrillated by homogenization to a degree than can be expressed as Brookfield viscosity exceeding 10,000 mPa.s (consistency 0.8%, 10 rpm).