Microfibrillated Cellulose Intermediate for Dry Transport and Redispersion
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Solution Overview
Problem
Existing methods for producing microfibrillated cellulose (MFC) face challenges such as high water content leading to uneconomical transportation, irreversible agglomeration during drying (hornification), and the need for costly chemical additives to prevent agglomeration, along with safety concerns due to dusting and the requirement for specialized equipment.
Innovation Solution
A process involving enzymatic removal of the primary wall of kraft pulp fibers, followed by drying to low water content, and subsequent mechanical disintegration at a different location to produce a dried cellulosic pulp intermediate, which can be easily transformed into MFC or NFC without specialized equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MFC is produced as a slurry with low solid content (1.5-2.5%), then high quality MFC is obtained, but transportation becomes uneconomical due to large volumes
Solution Approach 1:
The patent applies phase transition by drying the MFC slurry to convert it from liquid phase to solid phase, reducing water content from 97-98% to less than 20%. This phase change enables economical transportation while maintaining the ability to restore the original slurry properties through rewetting at the destination
Solution Approach 2:
The patent applies preliminary action by performing drying and stabilization treatments before transportation, and then performing rewetting and disintegration treatments after transportation. This sequence allows the material to be in a transport-friendly state during transit and restored to its functional state upon arrival
2Volume of moving object
If MFC is dried to reduce water content, then transportation efficiency improves, but irreversible agglomeration (hornification) occurs during drying
Solution Approach 1:
The patent applies preliminary action by removing the primary wall structure before drying, which prevents hornification during the subsequent drying process. This preliminary structural modification enables the material to withstand drying without irreversible agglomeration
Solution Approach 2:
The patent inverts the conventional approach by not trying to prevent hornification during drying through additives, but rather by removing the primary wall beforehand to eliminate the hornification problem at its source, allowing drying to proceed without chemical modifications
3Reliability
If chemical modifications or additives are used to prevent hornification, then redispersibility is maintained, but product cost increases and harmful substances are introduced
Solution Approach 1:
The patent applies the extraction principle by removing the primary wall structure from the cellulose fibers, which eliminates the need for chemical additives to prevent hornification. This structural extraction achieves the desired redispersibility without introducing harmful substances or increasing costs
Solution Approach 2:
The patent applies self-service by using the cellulose structure itself (after primary wall removal) to prevent hornification, rather than relying on external additives. The modified cellulose structure inherently resists irreversible agglomeration during drying
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
Enables economical and safe transportation of MFC intermediates, preserving fiber integrity for easy conversion into MFC or NFC, reducing the need for chemical additives and specialized equipment, while maintaining high surface area and dispersibility.
Implementation Method 1
treating cellulosic fibres to remove at least a major part of the primary wall of the fibres
Implementation Method 2
drying the treated fibres to a water content of less thatn 20 wt-%
Implementation Method 3
disintegrating the wetted fibres by mechanical means to obtain the final product
Data Source
AI summary
The invention concerns a method for the production of highly refined or micro- fibrillated cellulose (MFC), comprising the steps of treating cellulosic fibres to remove at least a major part of the primary wall of the fibres, drying the treated fibres, rewetting the treated fibres, and disintegrating the wetted fibres by me- chanical means to obtain the final product. The invention further concerns dried cellulosic pulp as an intermediate product of the method, having an aver- age fibre length of at least 0.4 mm, while less than 50 % of the primary wall material of natural untreated fibres is left in the intermediate product. Instead of transporting large amounts of dilute MFC dispersion the invention enables transport of the dry intermediate product to the MFC end user, who would complete the process by turning the intermediate product to final MFC by use of standard disintegrating devices.