Water-Soluble Alkyl Ether Cellulose Binder for Ceramic Extrusion
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Solution Overview
Problem
The formation of ultra-thin wall ceramic honeycombs often encounters die plugging issues during the extrusion process due to the presence of large particles, fibers, and agglomerates, which increases extrusion pressure and requires frequent screen and die cleaning, affecting the integrity and strength of the final product.
Innovation Solution
A method involving the use of a water-soluble alkyl ether cellulose binder with less than 300 insoluble fibers per gram, such as methyl cellulose, hydroxypropyl methyl cellulose, or hydroxyethyl methyl cellulose, is employed to minimize die plugging by reducing the number of insoluble fibers, allowing for smooth extrusion and maintaining cell integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional binders with high fiber content are used, then binder strength and green body integrity are improved, but die plugging occurs and extrusion pressure increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the binder by using water-soluble alkyl ether cellulose with controlled molecular weight and substitution degree. This creates a binder that provides sufficient green strength through molecular adhesion rather than fibrous network, eliminating die plugging while maintaining integrity.
Solution Approach 2:
The patent replaces the mechanical fibrous reinforcement mechanism with a molecular-level adhesive mechanism. The water-soluble alkyl ether cellulose forms strong molecular bonds with ceramic particles and between layers, providing green strength without the mechanical fiber structure that causes die plugging.
2Manufacturing precision
If ultra-thin wall honeycombs are formed, then product precision and wall thickness requirements are met, but die plugging and extrusion difficulties increase
Solution Approach 1:
The patent modifies the extrusion system parameters by using a binder with optimized molecular weight (10,000-1,000,000) and substitution degree (1-3 alkyl groups per anhydroglucose unit). These parameter changes create a paste with ideal flow characteristics for ultra-thin wall extrusion without plugging.
Solution Approach 2:
The water-soluble alkyl ether cellulose acts as an intermediary substance that mediates between the ceramic particles and the extrusion process. It provides lubrication and flowability during extrusion while maintaining structural integrity, enabling ultra-thin wall formation without die plugging.
3Reliability
If frequent screen and die cleaning is performed, then die plugging is prevented, but production time is lost and productivity decreases
Solution Approach 1:
The binder system provides self-service by maintaining paste stability and flow characteristics throughout the extrusion process. The water-soluble alkyl ether cellulose prevents particle settling and maintains uniform viscosity, allowing continuous extrusion without cleaning interruptions.
Solution Approach 2:
The patent enables continuous extrusion operation by using a binder that maintains paste homogeneity and flowability over extended periods. The water-soluble alkyl ether cellulose prevents separation and plugging, allowing the extrusion process to continue without interruption for screen or die cleaning.
Data Source
AI summary
The disclosure provides for a mixture suitable for extrusion and firing to form a ceramic honeycomb substrate, said mixture comprising a batch composition selected from the group consisting of a cordierite batch composition and an aluminum titanate batch composition, an optional pore former material; a binder material and water; wherein said binder is a methyl ether of cellulose binder having a count of less than 300 water-insoluble fibers per gram of binder material.