Methylcellulose Binder for Ceramic Extrusion Tonset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of ceramic bodies, such as silicon carbide, cordierite, mullite, and aluminum titanate, is limited by the Tonset temperature, which restricts the batch feed rate through extruders, leading to higher processing costs and potential distortions during heating.
Innovation Solution
Incorporating a cellulose-based polymer, specifically methylcellulose with a concentrated micro-calorimetry thermal response, which exhibits an exothermic peak below a transition onset temperature, to increase the Tonset temperature, allowing for higher batch feed rates and reduced processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional binder systems are used for ceramic extrusion, then good drying behavior and plasticity are achieved, but Tonset temperature is limited which restricts batch feed rate
Solution Approach 1:
The patent changes the chemical composition parameters of the binder system by incorporating cellulose ethers with specific molecular weights and degrees of substitution. This modifies the thermal response characteristics of the batch, shifting the Tonset temperature to higher values while maintaining extrusibility at lower temperatures through controlled gelation behavior.
Solution Approach 2:
The patent creates a composite binder system combining cellulose ethers (MC, HPMC, or HEMC) with other ceramic processing aids. This composite approach leverages the unique gelation properties of cellulose ethers to achieve both low-temperature plasticity for extrusion and high Tonset for increased feed rates, resolving the contradiction between extrusibility and productivity.
2Productivity
If batch feed rate is increased to improve productivity, then processing costs are reduced, but distortions occur during heating due to limited Tonset
Solution Approach 1:
The patent applies preliminary action by selecting binder systems that pre-establish controlled gelation characteristics before extrusion. The cellulose ether binders are chosen to gel at specific temperatures below Tonset, creating a rigidified structure in the green body that prevents distortions during subsequent heating and drying processes, thereby maintaining manufacturing precision at high feed rates.
Solution Approach 2:
The patent exploits phase transitions of cellulose ether binders, specifically the gelation transition that occurs at controlled temperatures. This phase change from sol to gel state provides structural support to the green body during drying and firing, preventing distortions and maintaining dimensional uniformity even when batch feed rates are increased to improve productivity.
3Ease of operation
If cellulose ethers are used as extrusion binders, then plasticity and drying behavior are improved, but high temperature gels form which may limit processing
Solution Approach 1:
The patent applies local quality by selecting cellulose ether binders with specific local molecular characteristics (degree of methoxylation, hydroxypropylation, and molecular weight) that create different gelation temperatures. This allows tailoring the binder system to gel at optimal temperatures below Tonset, ensuring adequate plasticity for extrusion while preventing premature gelation that would limit processing.
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 increased Tonset temperature enables higher batch feed rates and reduces processing costs by maintaining uniformity and integrity in ceramic body formation, while preventing distortions during heating.
Implementation Method 1
an exothermic peak below a transition onset temperature. The exothermic peak has a maximum intensity at a temperature of at least 52° 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 that correlates to an increased Tonset.