Methylcellulose Binder for High Tonset Ceramic Extrusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of ceramic bodies, such as silicon carbide, cordierite, mullite, and aluminum titanate, faces limitations in batch feed rate due to the Tonset temperature, which affects the processing costs and integrity of the final product, as existing binder systems do not provide sufficient high Tonset values.
Innovation Solution
Incorporating a cellulose-based polymer, specifically methylcellulose with defined micro-calorimetry thermal responses, such as endothermic peaks above 69°C upon dehydration, exothermic peaks below 48°C upon rehydration, and a cloud point above 62°C, into ceramic precursor batch compositions to enhance the Tonset temperature and improve processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binder systems are used in ceramic precursor batches, then the batch can be processed through extrusion, but the Tonset temperature is limited which restricts batch feed rate and increases processing costs
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by incorporating specific cellulose ethers (methylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose) with controlled degrees of substitution and molecular weights. This compositional parameter change raises the Tonset temperature from conventional limits to above 80°C, enabling higher batch feed rates through the extruder while maintaining batch integrity
Solution Approach 2:
The patent creates a composite binder system combining cellulose ethers with ceramic-forming ingredients. The cellulose ether component provides high-temperature stability and gelation control, while the inorganic ceramic ingredients form the final product structure. This composite approach allows the batch to withstand higher temperatures during extrusion without premature gelation, thus increasing productivity
2Productivity
If higher batch feed rates are achieved by increasing Tonset, then processing costs are reduced, but the batch rheology becomes more challenging to control
Solution Approach 1:
The patent performs preliminary characterization of the cellulose ether binder properties (intrinsic viscosity, degree of substitution, gelation temperature) before formulating the batch. This preliminary action allows precise prediction and control of the batch rheology at elevated temperatures, making it easier to manage higher feed rates without unexpected viscosity changes or gelation issues during extrusion
Solution Approach 2:
The patent establishes feedback control by monitoring the batch rheology at processing temperatures and adjusting extrusion parameters accordingly. The use of cellulose ethers with defined thermal responses provides predictable rheological behavior that can be controlled through feedback mechanisms, maintaining product quality even at higher feed rates
3Ease of operation
If cellulose ethers are used as extrusion binders to impart plasticity, then good drying behavior is achieved, but the gelling behavior may cause distortions during heating
Solution Approach 1:
The patent applies local quality control by selecting cellulose ethers with specific regional properties (degree of methoxy substitution, hydroxypropyl substitution) that provide plasticity in the extrusion zone while controlling gelation in the drying zone. The gradient in substitution patterns creates different functional zones within the binder molecule, enabling good drying behavior without distortion-causing gelation
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 use of these cellulose-based polymers increases the Tonset temperature, allowing for higher batch feed rates and reduced processing costs, while maintaining uniform physical properties and integrity of the ceramic bodies.
Implementation Method 1
The cellulose-based polymer includes a methylcellulose showing a micro-calorimetry thermal response comprising, upon dehydration, at least one endothermic peak above a gelation onset temperature
Implementation Method 2
The gelling behavior facilitates rapid drying while preventing distortions that can occur with other binder systems as they are heated
Implementation Method 3
The cellulose-based polymer includes a methylcellulose showing a micro-calorimetry thermal response comprising, upon rehydration, at least one exothermic peak below a transition onset temperature
Implementation Method 4
The cellulose-based polymer includes a methylcellulose having a cloud point above 62°C
Data Source
AI summary
A precursor batch composition that can be used to make porous ceramic articles is provided. The batch composition includes a cellulose-based polymer and, in particular, a methylcellulose showing a specified micro-calorimetry thermal response fingerprint. The methylcellulose can also have a cloud point above a specified temperature.