Grinding Cellulose Ether with Cationic Surfactant
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Solution Overview
Problem
Existing processes for grinding cellulose ether result in agglomeration and adherence to mill walls, leading to product loss and a significant risk of dust explosions during handling and storage.
Innovation Solution
A process involving grinding cellulose ether with 20-90% water and a cationic surfactant in a mill, optionally drying during grinding, which prevents agglomeration and adherence, reducing the risk of dust explosions by producing antistatic, finely sized products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cellulose ether is ground using conventional mills (hammer mill, vibration mill, gas jet impact mill), then grinding is achieved, but the moist cellulose ether agglomerates and adheres to the walls of the mill causing product loss
Solution Approach 1:
A cationic surfactant is introduced as an intermediary substance that mediates between the cellulose ether particles and the mill walls. The surfactant adsorbs onto the cellulose ether particles and to the mill walls, creating a protective layer that prevents direct adhesion and agglomeration of the cellulose ether to the mill walls, thereby preventing product loss.
Solution Approach 2:
The invention changes the surface charge parameter of the cellulose ether particles from neutral or negative to positive by introducing a cationic surfactant. This parameter change alters the interaction between particles and mill walls, preventing adhesion and agglomeration. The surfactant concentration and type are optimized to achieve the desired effect.
2Productivity
If cellulose ether is ground using conventional mills, then grinding is achieved, but the products exhibit a considerable risk of dust explosions upon handling and storage
Solution Approach 1:
The cationic surfactant acts as a mediator that reduces the dust explosion risk by forming a protective coating on the cellulose ether particles. This coating reduces the combustibility of the dust particles, thereby lowering the explosion hazard during handling and storage while maintaining grinding efficiency.
Solution Approach 2:
The invention changes the electrical and surface properties of the cellulose ether particles by introducing a cationic surfactant. This parameter change reduces the static electricity accumulation that leads to dust explosions, making the product safer for handling and storage while maintaining grinding efficiency.
3Ease of manufacture
If anionic surfactants are used in the grinding process, then some grinding benefits are achieved, but the cellulose ether compositions are more biodegradable leading to shorter storage life
Solution Approach 1:
Instead of using conventional anionic surfactants, the invention inverts the approach by using cationic surfactants. This inversion results in compositions that are less biodegradable, thereby extending storage life while maintaining ease of manufacture and grinding processability.
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 yields a higher product yield with reduced risk of dust explosions and improved biodegradability, enhancing storage life and handling safety.
Implementation Method 1
due to their positive charge the cationic surfactants are able to adsorb to the cellulose ether more efficiently than anionic surfactants
Implementation Method 2
the cellulose ether does not stick to the walls of the mill, rendering a higher product yield... the products obtained with these processes exhibit a considerable risk of dust explosions upon handling and when stored
Data Source
AI summary
The invention relates to a process for grinding cellulose ether comprising the steps of: a) grinding a cellulose ether comprising 20 to 90 wt % of water, based on the total weight of cellulose ether and water, and a cationic surfactant in a mill; and b) optionally drying the mixture while grinding, prior to or following the step of grinding.