Cellulose Pulp Pretreatment for Nanofibrillated Cellulose Production
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Solution Overview
Problem
Current methods for producing nanofibrillated cellulose (NFC) are energy-intensive and limited in production capacity, with chemical modifications resulting in undesirable grades for all applications, necessitating improved pretreatment and manufacturing methods.
Innovation Solution
A pretreatment process involving an aqueous suspension of native cellulose pulp treated with an acid to lower pH, followed by addition of a water-soluble salt and adjustment to a higher pH using a base, enhances mechanical disintegration, resulting in NFC with improved properties such as reduced turbidity and increased viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical modification methods are used to produce nanofibrillated cellulose, then production capacity is improved, but the resulting grades are not desirable for all applications
Solution Approach 1:
The patent applies preliminary action by treating the cellulose pulp with acid before mechanical disintegration. This pre-treatment modifies the cellulose structure in advance to facilitate subsequent mechanical fibrillation, enabling high production capacity without requiring chemical modification after disintegration, thus maintaining versatility for different applications.
2Adaptability or versatility
If mechanical disintegration is used to produce nanofibrillated cellulose, then product versatility is maintained, but energy consumption is high and production capacity is limited
Solution Approach 1:
The patent applies preliminary action by treating the cellulose pulp with acid before mechanical disintegration. This pre-treatment modifies the cellulose structure in advance to facilitate subsequent mechanical fibrillation, enabling high production capacity without requiring chemical modification after disintegration, thus maintaining versatility for different applications.
Solution Approach 2:
The patent applies parameter changes by modifying the pH of the cellulose suspension to below 4 using acid treatment. This parameter change alters the cellulose properties to make it more susceptible to mechanical disintegration, thereby reducing the energy required for fibrillation while maintaining product versatility.
3Productivity
If acid treatment is applied to lower pH below 4, then mechanical disintegration is enhanced, but additional processing steps are required
Solution Approach 1:
The patent applies parameter changes by modifying the pH of the cellulose suspension to below 4 using acid treatment. This parameter change alters the cellulose properties to make it more susceptible to mechanical disintegration, thereby reducing the energy required for fibrillation while maintaining product versatility.
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 method enhances NFC production efficiency and economy, achieving higher yields with less energy while producing a product with excellent gelling properties and transparency, suitable for various applications without chemical residues.
Implementation Method 1
an aqueous suspension of native cellulose pulp is brought into contact with an inorganic or organic acid and agitated to obtain pH of the suspension below 4
Implementation Method 2
the pH of the suspension is adjusted with a base to above 7
Data Source
Figure 1~2(b)
Figure 3~4
AI summary
The invention relates to pretreating of native cellulose pulp in the manufacture of nanofibrillated cellulose, and to a nanofibrillated cellulose product obtainable by the method.