Microfibrillated Cellulose Stabilization via Thermostable Biocide
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Solution Overview
Problem
Microfibrillated cellulose is highly susceptible to microbiological degradation, leading to reduced usability and efficiency in papermaking processes, as it tends to clog filters and sieves, and has limited storage stability in moist form.
Innovation Solution
A process involving mechanical shearing of an aqueous cellulose mixture containing 30-70% cellulose fibers at temperatures between 40°C to 120°C in the presence of a thermostable biocide, resulting in microfibrillated cellulose with an average fiber length of 500-1300 μm and at least 15% of fibers ≤200 μm, which enhances stability and storage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If microfibrillated cellulose is produced by mechanical treatment, then fiber defibrillation and surface area are improved, but susceptibility to microbiological degradation increases
Solution Approach 1:
A biocide is introduced as an intermediary substance to protect the microfibrillated cellulose from microbiological degradation. The biocide acts as a mediator between the cellulose and microorganisms, preventing harmful interactions while allowing the cellulose to maintain its high surface area and functional properties.
Solution Approach 2:
The chemical composition of the cellulose system is changed by adding biocidal agents. This parameter change transforms the system from one that is highly susceptible to degradation to one that is stabilized, without altering the fundamental microfibrillated structure or its surface area characteristics.
2Ease of operation
If microfibrillated cellulose is stored in moist form, then usability and dispersion are improved, but storage stability decreases due to microbiological growth
Solution Approach 1:
The biocide serves as a protective intermediary that enables the cellulose to be stored in its dispersed, moist state without undergoing microbiological degradation. This allows the material to maintain both its usability characteristics and storage stability simultaneously.
Solution Approach 2:
The biocide is added in advance to prevent microbiological degradation before it can occur during storage. This prior protective measure cushions against the potential harm of storing moist cellulose, enabling long-term stability while maintaining dispersion performance.
3Ease of manufacture
If oxidizing compounds are used to modify cellulose surface, then defibrillation is enhanced, but long time stabilisation is compromised due to quick consumption
Solution Approach 1:
The patent recognizes that oxidizing compounds like hydrogen peroxide are consumable and get quickly used up during the process. Rather than relying on these short-lived agents for long-term stabilization, the invention uses biocides that provide sustained protection over time.
Solution Approach 2:
The biocide acts as a long-lasting intermediary that replaces the short-lived oxidizing compounds for the specific function of stabilization. While oxidizing agents provide initial defibrillation enhancement, the biocide takes over the role of maintaining stability over extended periods.
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 stabilizes microfibrillated cellulose against microbiological degradation, allowing for extended storage in moist form and improving paper strength properties such as dry breaking length, internal bonding strength, and stiffness, while maintaining effective dispersion and filtration performance.
Implementation Method 1
in the presence of at least one thermostable biocide
Implementation Method 2
subjecting an aqueous mixture comprising 30 to 70% by weight of cellulose containing fibers to mechanical shearing
Data Source
AI summary
The present invention relates to a process for the production of microfibrillated cellulose composition, wherein the microfibrillated cellulose has an average fiber length in the range from 500 to 1300 μm and a percentage of fiber length in the category ≤200 μm of at least 15%, obtained by subjecting an aqueous mixture comprising 30 to 70% by weight of cellulose containing fibers to mechanical shearing at a temperature in the range of from ≥40° C. to ≤120° C. in the presence of at least one thermostable biocide, to the microfibrillated cellulose composition obtained in this process and their use in a process for production of paper, card and board comprising draining a paper stock comprising the microfibrillated cellulose composition with sheet formation in the wire.